Grazing Factsheets

Noxious/Invasive Species
(Poisonous Plant)

Invasive Species
Reed Canary Grass
Johnsongrass

Poisonous Plants
Common Cocklebur
Eastern Black Nightshade
Hemp dogbane
Horsenettle
Jimsonweed
Milkweed
Poison Hemlock
Common Pokeweed
White Snakeroot
Black Locust
Bouncing Bet
Bracken (or Brake Fern)
Buffalo-bur
Buttercups (pasture & Meadows)
Buttercups (Woods)
Climbing Bittersweet
Corn Cockle
Great Lobelia or Blue Cardinal Flower
Ground Ivy or Creeping-Charlie
Hemp or Marihuana
Hogwort
Horsetails and Scouring Rushes
Indian Tobacco & Pale Spiked Lobelia
Oaks
Ohio Buckeye
Pigweed
Potato
Rocket Larkspur
Sneezeweeds
Star-of-Bethlehem
Water Hemlock
White Sweet Clover
Wild Cherries
Yews

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Noxious/Invasive Species

Reed Canary Grass

Illinois

NOTE: Reed Canary grass is NOT recommended in Illinois due to aggressive nature.

General Information

Reed canary grass is a tall-growing, cool-season perennial with a rhizomatous root system. Tolerant of flood and drought, and is used for pasture, hay and erosion control. Reed Canary grass is one of the first grasses to begin spring growth.

Animals grazing reed canary grass during spring and summer perform similar to those grazing orchard grass, timothy or brome, and they perform better than animals grazing fescue. However, Reed Canary grass is not as well suited for fall and winter grazing as tall fescue, due to being one of the first cool-season grasses to stop growing and lose of green color. Reed Canary makes excellent hay for horses, who have shown preference over good quality timothy hay.

Reed Canary grass was first used in the southern corn belt to control erosion in ditches, waterways and gullies, and excellent for that purpose wherever the grass is adaptable. Several improved varieties of reed canary grass are available. Breed and Rise are high alkaloid varieties while Palaton and Venture have low alkaloid levels.

Adaptability

No other forage plant is more adapted to wet, marshy areas as Reed Canary grass, and has withstood flooding for as long as 49 days without permanent injury. Reed Canary grass also has been found to be one of the most drought tolerant of the cool-season grasses.

Reed Canary grass has been widely used in the northern region of the central United States for many years, is adapted to all of Illinois. Some of the most vigorous, productive stands are in the extreme southeast part of the state.

CAUTION: Reed Canary grass is very aggressive and has been removed from NRCS standards.

Establishment

Reed Canary grass may be established in the same manner as other cool-season grasses. Purchase only pure live seed to be seeded during August or early in the spring. Check with Natural Resources Conservation Service or University Extension for current recommended seeding rates and dates.

Management

Reed Canary grass may be used as sod in areas where seeding is difficult. Small pieces of sod are embedded at one to two-foot intervals across gullies in early spring, or in the fall when the soil is wet. Shoots will emerge through six to eight inches of sediment.

Reed Canary grass should not be allowed to get higher than 14 inches for best results in a pasture system. In pure stands, reed canary grass will respond to extremely high rates of nitrogen, and will make more summer growth under these conditions than any other cool-season grass in Illinois.

Reed Canary grass can be made into hay, but should not be allowed to become coarse and stemmy. Because of early spring growth, graze the grass first to delay the haying period. If cut for hay without grazing the first growth, mow grass when heads first begin to appear.

Legumes can be maintained with Reed Canary grass despite the ability to form thick sod. Upright growth characteristic allows substantial light to reach the legumes. In wet, low areas, ladino or alsike clover make good companion legumes. On upland sods, ladino, red clover, birdsfoot trefoil and alfalfa grow well with Reed Canary grass.

Seed production usually is a problem with Reed Canary grass because of shattering. The seed head matures downward from the top of the panicle, and the first mature seed shatters before the remainder of the seed in the head is ready to harvest. Only two or three days separate the ripening of the first seed and the start of extreme shattering. For seed production, nitrogen should be applied from December through January. Seed yields will be increased by applying 100 to 125 pounds of nitrogen per acre.

Where to Get Help

For more information about reed canary grass, contact your local office of the USDA Natural Resources Conservation Service, listed in the telephone directory under “U.S. Government,” or the University of Illinois Extension.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audio tape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.”

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Noxious/Invasive Species

Johnsongrass

Illinois

General Information

Johnsongrass is a perennial sorghum that closely resembles sudan grass, is native to the Mediterranean region, and was introduced into the United States about 1830 from an unknown source.

Taken by Col. William Johnson to Selma, Alabama, for use as a forage plant, Johnsongrass grew luxuriantly there, and became known as Johnsongrass.

In Illinois, Johnsongrass is usually not planted or thought of as a desirable species, but is hayed, and grazed incidental to other grasses. Good quality hay and grazing can be expected. Johnsongrass is considered a pest and a noxious weed in cultivated areas.

Characteristics

Johnsongrass is an erect, perennial, warm-season plant that grows from three to 10 feet high and is sometimes confused with switch grass or eastern gamagrass.

The leaves usually have reddish spots on them from a pathogen. Stems are about the size of a pencil. The broad-bladed leaves are one-half inch to one inch wide with a distinct, light green midrib. The plant usually grows in bunches.

Branching seed heads form at the tip of the stem becoming reddish at maturity. Established plants have large, fleshy root stock called rhizomes, often as much as one-half inch in diameter.

The most undesirable forage characteristic of the plant is its tendency to be toxic under certain conditions.

Adaptability

Johnsongrass is adapted to a wide range of soils, has spread over much of the United States, and does not seem to adapt well to very shallow, wet or saline soils.

Establishment

Johnsongrass readily establishes from seeds or from rhizomes.

Management

Johnsongrass is very palatable when green and growing, and is easily grazed out of grasslands.

To make the best pasture, graze under a planned grazing system.

Leave about eight inches of leaf, followed by a recovery period of 30 to 45 days, depending upon growing conditions.

Under careful management, maintaining a full stand of Johnsongrass can be difficult. In fact, grazing is a recommended control measure.

Haying operations should leave about six inches of leaf. Johnsongrass should be cut when the plants are in the early boot stage. Forage yields of two to five tons per acre are possible, with crude protein of 10 to 14 percent and total digestive nutrient values of 50 to 60 percent.

Toxic Properties

Johnsongrass responds well to nitrogen fertilizer, but has the potential for nitrate poisoning.

The risk is greater on fields fertilized heavily with nitrogen during wet, cool, cloudy weather, or even drought.

The grass does not assimilate the nitrogen quickly enough to prevent toxic build-up under these conditions. The hay is also susceptible because the nitrogen level does not decrease with time.

Nitrate poisoning affects grazing animals very suddenly.

Prussic acid poisoning is normally associated with stress in the grass.

Dangerous times are immediately after a killing frost or in young regrowth after a drought.

Prussic acid levels in the plant will decrease with time, unlike nitrates which do not decrease with time.

Generally, one week is needed on standing plants, and about three weeks on ensilage.

To reduce the risk of prussic acid poisoning, do not turn hungry animals into suspect pasture. Also, release only a few cattle, and observe their reaction. Animals also are affected quickly by prussic acid poisoning.

Where to Get Help

For more information about big bluestem, contact the local Natural Resources Conservation Service listed in the telephone directory under “U.S. Government,” or the University of Illinois Cooperative Extension Service.

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Noxious/Invasive Species

Common Cocklebur
(Poisonous Plant)

Illinois

Plant Characteristics

Xanthium pensylvanicum: This coarse, widely branching, annual herb can grow to .2 to 1.7 m (1-2 ft.) tall. The leaves are alternate, simple, coarsely pubescent, shallowly 3 to 5 lobed. The flowers are green, inconspicuous, male and female borne in separate clusters. The fruit is a bur, broadly cylindrical, to nearly spherical, spiny, 1.5 to 3 cm long, including spines. The two seeded bur is greenish to brown at maturity. This plant is a native annual weed, found throughout the south and across much of the Midwest in row crop fields, gardens, roadsides, and other areas exposed to full sun. It is most abundant in fertile, moist soils.

Toxicity

The toxic principle is the glycoside, hydroquinone. It is concentrated in the seeds and seedlings (cotyledon stage). Mature plants are distasteful to animals and contain less of the toxin. The tender, juicy cotyledons, which are long and narrow, contain carboxyatractyloside, which affects the nervous system.

Symptoms

Signs of poisoning include anorexia, depression, and weakened heartbeat. Swine are the animals most commonly poisoned. They root up and ingest the two-leaf stage of the plant in the springtime. Symptoms include vomiting and gastrointestinal irritation with occasional diarrhea. Large amounts often cause nervous symptoms including spasmodic running movements and convulsions. Chickens and other animals have also been poisoned. Sheep have been known to eat the two leafed stage plants as well.

Treatment

Treatment is of little to no value once the symptoms have been observed.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition Ohio State University.

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Noxious/Invasive Species

Eastern Black Nightshade
(Poisonous Plant)

Illinois

Plant Characteristics

Solanum nigrum: This is an annual, thorn-less, essentially glabrous herb, .1 to1 m tall. Leaves alternate, sinuately or coarsely toothed with slight pubescene on the undersurface, 5 to 10 cm long and 2 to 5 cm wide. Flowers are white to purple borne in an open cluster, 6 to 8mm broad. Fruit is shiny and black when ripe and produces several seeds, which are 5 to9 mm in diameter. Can be found throughout the south and in most of Illinois; grows along stream banks, thickets, roadsides, row crop fields and other open disturbed areas.

Toxicity

A toxic alkaloid, solanine, has been isolated from this group of plants. Toxicity of these plants varies depending upon maturity, environment and portion of the plant ingested. The berries are the most toxic part and are more toxic when they are matured. The berries of both Carolina horsenettle and black nightshade are green when immature. However, horsenettle berries turn yellow when mature and nightshade berries become purplish black. The leaves are also toxic, but to a lesser degree.

Symptoms

All classes of livestock and humans have been poisoned. Two syndromes have been described: acute and chronic. The acutely poisoned animals are characterized by irritation of the mouth and gastrointestinal lesions. In the chronic form, unthriftiness, jaundiced mucous membranes, abdominal dropsy and constipation have all been seen.

Treatment

Non-specific.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

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Noxious/Invasive Species

Hemp dogbane
(Poisonous Plant)

Illinois

Plant Characteristics

Apocynum cannabinum: Hemp dogbane, Indian hemp, Choctaw root, rheumatism weed and snake’s milk are some of the common names for this native perennial. This erect, branching, perennial can be .8 to 1.8 m (1-4 Ft.) tall with a silky sap arising from creeping, underground root stock. It reproduces by creeping roots and seeds. The leaves are opposite and ovate to elliptic, 4 to 14 cm long, 1.5 to 6 cm wide with smooth margins. The underside of the leaf is finely-hairy. Dogbane branches freely, unlike common milkweed. The flowers are white to greenish in terminal flat-topped clusters, usually overtopped by the leafy branches. The fruit is long and slender, paired drooping follicles, 10 to 22 cm long (4-8 inches) and 2 to 3 cm in diameter. The seeds are elongated and smooth. This plant is found throughout the south and much of the Midwest. It is abundant in the edges of woods, roadsides, pastures, waste areas and in some crop fields.

Toxicity

A resinoid and glucoside are found in the leaves and stems of this plant, whether green or dry. It is quite toxic and requires only 15-30 grams (< 1 ounce) of green leaves to kill a horse or cow. Livestock can be poisoned in spring, summer and fall.

Symptoms

Symptoms include increased temperature and pulse, sweating, dilated pupils and off feed, along with refusing to eat or drink. The mucous membranes (mouth and nostrils) are discolored and extremities are cold.

Treatment

Intravenous fluids and gastric protectives are suggested.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

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Noxious/Invasive Species

Horsenettle
(Poisonous Plant)

Illinois

lant Characteristics

Solanum carlinense: This plant is in the nightshade family. This plant is sometimes called bull nettle, devil’s potato and wild tomato. This is a perennial, thorny herb, .2 to .8 m tall that can spread by rhizomes and seeds. Leaves are alternate, simple, irregularly pinnately lobed, 7 to 12 cm long, 3 to 8 cm wide, stellate pubescent. The flowers are white to purple and are star shaped with five bright yellow anthers, 2.3 to 3.1 cm broad: borne in few-flowered, terminal racemes. Fruit is green, but turns yellow, like a small tomato, 1 to 1.5 cm in diameter. Plants are found throughout the south, but are also common in the Midwest in pastures, old fields, waste areas and sometimes in cultivated fields. Horsenettle is characterized by hard, sharp, yellowish spines found on the stems and leaves. They are easily found in pastures since most animals avoid eating it.

Toxicity

All parts of the plant are poisonous, with the level of solanine being highest in the fall. Toxicity of these plants varies depending upon the maturity, environment and portion of the plant ingested. The berries are the most toxic when they are mature. The berries of both Carolina horsenettle and black nightshade are green when immature. However the horsenettle berries turn yellow when mature and the black nightshade berries become black. The Leaves are toxic also, but to a lesser degree.

Symptoms

All classes of livestock and humans have been poisoned by them. Two syndromes have been described: acute and chronic. The acutely poisoned animal is characterized by irritation of the mouth and gastrointestinal lesions. In the chronic form, unthriftiness, jaundiced mucous membranes (mouth and nostrils), abdominal dropsy and constipation have all been seen.

Treatment

Non-specific.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

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Noxious/Invasive Species

Jimsonweed
(Poisonous Plant)

Illinois

Plant Characteristics

Datura stramonium: This is a foul-smelling glabrous annual, .5 to 1.5 m tall with a green to purple-tinged stems. The leaves, resemble a poinsettia, are altenate, coarsely and irregularly toothed, 7 to 15 cm long, 2 to 12 cm wide. Flowers are large white to lavender, tubular (funnel shaped), 7 to 10 cm (2-5 inches long and 1-2 inches across). The fruit is a distinctive, hard, prickly, many seeded capsule that splits into four sections. This erect dry spiny capsule is 2.5 to 4 cm long and 2 to 2.5 cm wide and contains many shiny black seeds. The plant is native to the tropics but is naturalized to most of Illinois and the Midwest. It is most abundant in fertile fields and gardens and barn lots.

Toxicity

The toxic principles of this common hog lot and barnyard plant are the alkaloids atropine, hyoscyamine and scopolamine. All parts of the plant are considered poisonous, whether green of dry. Usually poisoning occurs from eating the dry plant in hay or silage or the seeds mixing in grain. However the seeds are particularly poisonous. Usually, this plant is not eaten except when other forage is unavailable. Cattle and swine are primarily affected but horses, poultry, dogs and humans have been affected. Cows can be poisoned by consuming one-half to one pound of the green plant.

Symptoms

Early symptoms include a weak and rapid pulse and heartbeat. The eyes are dilated, the mouth and other mucous membranes are dry and animals may appear blind. Later, slow breathing may be observed as well as lowered temperature, convulsions or coma. After eating the plants sheep have been observed to have abnormal leg movements, disturbed vision, intense thirst and to bite at imaginary objects in the air.

Pregnant sows consuming jimson weed during their second and third months of gestation have produced deformed pigs. Some pigs may be born alive but exhibit varying degrees of flexed hips, stifles and forelegs. The hocks may be overextended.

Treatment

Non-specific. Weeds should be destroyed in order to prevent problems.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

Download This Factsheet PDF

Noxious/Invasive Species

Milkweed
(Poisonous Plant)

Illinois

Plant Characteristics

Asclepias tuberose, and other species: Common milkweed, is an erect perennial that spreads by creeping roots and seeds. Stems can reach 3-6 feet and are unbranched and covered with short downy hairs. The leaves are oblong, 3-8 inches long with a rounded to tapered leaf tip and base. The leaves are attached directly to the stem. The plant has a milky sap arising from thick rootstock or rhizomes. The leaves are opposite and whorled or rarely alternate, simple linear to widely ovate. The under side of the leaves are covered with fine velvet-like hairs. The upper surface, which can be hairless or hairy, shows a prominent white midrib. The flowers are borne in a large ball-like cluster and are sweet smelling, pink-lavender in color and bloom from June to August. The fruit is an elongated follicle splitting on one side and releasing many seeds topped with white silky hairs that enables then to be widely dispersed by the wind. The milkweed genus is found throughout the southern states, since it is native to North America, in reduced tillage fields, along roadsides, fence rows, open woods, pastures and waste areas. It grows best in warm, dry soils with full sunlight.

Toxicity

All parts of the plant, whether green or dry in hay are toxic to cattle, horses, sheep, goats and poultry. Various species of milkweeds have yielded resinoids, alkaloids and glycosides. Animals consuming 2% of their body weight of the toxic plant can cause symptoms.

Symptoms

Losses usually occur when animals are forced to graze the plant due to lack of other forage. Usual signs include staggering, depression, weakness, rapid and weak pulse, labored respiration and dilated pupils. Animals go down and exhibit tetanic spasms before going into a coma and dying, death is rare.

Treatment

Laxatives and intravenous fluids are suggested.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

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Noxious/Invasive Species

Poison Hemlock
(Poisonous Plant)

Illinois

Plant Characteristics

Conium maculatum: This is a glabrous, branching biennial herb that can grow to 3 m (10 ft.) tall with a hollow spotted stems arising form a thick taproot. This tall erect biennial produces a vegetative rosette the first season of growth and an upright reproductive stem in the second season. Hemlock usually has only one fleshy taproot; there are partitions in a hollow area at the juncture of the root; stem and upper stem leaves are divided. The basal and stem leaves are finely dissected with a lace-like appearance, resembling the non poisonous wild carrot. Flower heads at the top of the plant are large one to three inches in diameter, white and umbrella-shaped. Flowers develop into a green, deeply ridged fruit with several seeds. The plant has an unmistakable and disagreeable mouse like odor. This plant grows in much of Illinois in waste areas, especially partially shaded, poorly drained sites, stream banks or edges of cultivated fields. This plant stays green into late winter and greens up early in the spring.

Toxicity

The poison hemlock contains coniine, an alkaloid, and eight other compounds that are capable of poisoning livestock, poultry and humans. The stems, leaves and mature fruits are all toxic but the roots are the most toxic. The leaves are more dangerous in the springtime, and the fruit in the most dangerous in the fall. Livestock can be severely injured by eating this plant, usually by eating contaminated fresh hay or silage.

Symptoms

Signs of poisoning include dilated pupils, weakness, staggering gait, and respiratory paralysis two to three hours after ingestion. Other symptoms include gastrointestinal irritation, nervousness, trembling, staggering, coldness of extremities, slow heartbeat and eventually coma and death.

Treatment

Respiratory stimulants may be used advantageously. Intestinal protectives are suggested.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

Download This Factsheet PDF

Noxious/Invasive Species

Common Pokeweed
(Poisonous Plant)

Illinois

Plant Characteristics

Phytolacca Americana: often called pokeberry. This is a perennial herb that can grow to 3 m (10 ft.) tall, often with many stems from a large fleshy root stock. This can grow from seeds as well. The stems are green to purplish, fleshy, hairless, hollow and smooth, they can reach a diameter of 4 inches. The leaves are alternate, light green, lanceolate, 8 to 23 cm (12-20 inches) long, 3 to 12 cm wide, glabrous, margins entirely. Flowers are white to purplish in drooping axillary reacemes, that bloom from July to August. The ripe fruit is black, juicy, many seeded and when mashed produces a red “ink”. The is distributed throughout the south and Midwest: most commonly on waste ground, fence rows, pastures and old home sites. Young leaves are often used as cooked greens; older leaves are quite poisonous.

Toxicity

The poisonous principles are oxalic acid and a saponin called phytolaccotoxin. In addition, alkaloids may also be present. The root of the plant is the most toxic portion, although all of the other parts of the plant contain smaller amounts of the toxic principles. Cattle, horses, swine and man have all been poisoned after consuming this plant. Recognizable clinical cases are rare, however. Swine are the most often affected since they often grub out the roots and eat them.

Poisoning occurs during spring, summer or fall. In the springtime humans cook the leaves and consume them. This “poke salad” is generally considered safe if the water in which the leaves are cooked is poured off.

Symptoms

The most commonly observed symptom is a severe gastroenteritis with cramping, diarrhea and convulsions. Postmortem lesions include severe ulcerative gastritis, mucosal hemorrhage and a dark liver. In most cases the animal recovers within 24-48 hours.

Treatment

Gastrointestinal protectives and sedatives are suggested.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

Download This Factsheet PDF

Noxious/Invasive Species

White Snakeroot
(Poisonous Plant)

Illinois

Plant Characteristics

Eupatorium rugosum: This is a perennial herb, .6 to 1.5 meters tall, with erect branched or unbranched stems arising from a mat of fibrous roots. Leaves are opposite, simple, ovate 3.5 to 17 cm long, 2.5 to 11 cm wide, crenate to serrate. Flowers showy, white: borne in open terminal clusters, blooming late in summer or fall. This is easily confused with relatives that are not poisonous. Positive identification requires the services of a trained botanist. Probably found in all of the southern states east of the Mississippi River except in the state of Mississippi. Plants grow well in rich moist soils and in deciduous woods or bordering streams. This plant is common through out most of Illinois.

Toxicity

The toxic principle has been identified as a alcohol called tremetol. Tremetol is unusual in that it is a fat soluble molecule that becomes concentrated in the milk of lactating animals. It is found in all parts of the plant whether green of or dry. All domestic livestock, some Laboratory animals, and human beings are all susceptible to the effects of this plant. Animals may be poisoned by consuming the actual plant or from ingesting milk form cows, sheep or mares that have eaten the plant. Drinking milk from cows eating white snakeroot has accounted for an illness called “milk sickness” and for deaths in humans.

Symptoms

Trembling is the most commonly observed sign. The condition has been called “trembles.” Animals are stiff and sluggish, stand with feet side apart and may eventually become recumbent. Slobbering, vomiting, sweating, labored and rapid breathing, dilated pupils, constipation and dribbling of urine are also seen. A ketone odor may be detected on the breath. Humans may exhibit delirium after drinking toxic milk. Death may be sudden, this affliction is what reportedly killed Abraham Lincoln’s mother.

Treatment

Laxatives may be of benefit but there is no specific treatment.

Information Sources

• Poisonous Plant of the Southern United States
• http://plants.usda.gov/
• Bulletin 762 Horse Nutrition, Ohio State University.

Download This Factsheet PDF

Noxious/Invasive Species

Black Locust
(Poisonous Plant)

Illinois

Plant Characteristics

Robinia pseudoacacia L: Black locust is a medium-sized tree reaching 60 feet in height and 1 to 2 ½ feet in diameter, although it may grow larger on favorable sites. The trunk is usually short, and divides 10 to 15 feet above the ground into several stout, ascending branches. The trunk and branches lack large thorns. The pinnately compound, alternately arranged leaves, 8 to 14 inches long, have 7 to 19 nearly sessile leaflets. The flowers appear after leaf emergence, in May or June, and are borne in drooping racemes 4 to 5 inches long. Each flower is about 1 inch long and very fragrant. Its fruit is a flattened brown pod, 2 to 4 inches long and about ½ inch wide, that contains 4 to 8 kidney-shaped, compressed seeds.

Occurrence

Black locust is apparently native in the United States from Georgia to Louisiana and Arkansas, north to Pennsylvania, West Virginia, southern Indiana, southern Illinois, southern Missouri, and eastern Oklahoma. It was commonly planted farther north, and escaped to become a tree of roadsides, open woods, and waste places. Black locust has been widely used for erosion control. It reproduces itself by seeds, and also spreads by underground stems.

Conditions of Poisoning

Animals have been poisoned from browsing black-locust sprouts, eating the pods and seeds, gnawing the bark, eating the leaves, and drinking water in which pods had remained for some time. Cattle are the most frequently poisoned of all animals. Horses are occasionally poisoned from gnawing the bark of black-locust trees to which they are tied.

Control

Woodlands and open pastures should be cleared of black-locust sprouts and seedlings. Do not let animals graze near black-locust trees or drink water containing the pods. Do not tie horses to black-locust trees.

Toxic Principles

The leaves, bark, flowers, and seed pods are poisonous. There are several substances in locust trees that appear to be toxic, but the principle one is robinine.

Clinical Signs

Animals stand with feet spread apart and do not respond to commands. The main clinical signs are rapid, irregular heartbeat, rapid, shallow respiration, pale mucous membranes, depression, occasional evidence of abdominal pain, diarrhea, and periods of nervousness. Death results from cardiac failure. Since many animals exhibit extreme depression, some veterinarians have referred to the action of the toxic principle as that of a narcotic.

Necropsy

There are no tissue changes characteristics of this poisoning.

Treatment

If you suspect black-locust poisoning, call a veterinarian at once. Any animal that shows suspicious signs after having fed on any part of the tree is in immediate danger of death. A hypodermic injection of digitalis to improve the heart action may be helpful. A veterinarian may administer other indicated treatment.

References

Reprinted by permission from Poisoning Plants of the Midwest and Their Effects on Livestock (Special Publication 24) by Robert A. Evers and Roger P. Link. Copyright 1972, Board of Trustees, University of Illinois.

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Noxious/Invasive Species

Bouncing Bet
(Poisonous Plant)

Illinois

Plant Characteristics

Saponaria officinalis L.: Bouncing bet is an erect perennial herb from 1 to 3 feet tall, with smooth, little-branched stems that arise from rhizomes. The oppositely arranged, elliptic leaves are 3 to 4 inches long, and have 3 to 5 main veins. The margins of the leaves lack teeth. The pink to white flowers, which appear form July to September, usually form congested clusters at the summits of the stems. The fruit is a many-seeded capsule that opens by 4 teeth. The seeds are round or kidney-shaped, black, and minutely roughened.

Occurrence

Bouncing bet, a native of the Old World, was formerly cultivated, but has escaped and become a weed of roadsides, railroad trackways, and fallow fields throughout North America. It seems to prefer sandy soil, and in such situations, forms sizable colonies.

Conditions of Poisoning

The abundance of bouncing bet along roadsides and in other wastelands makes it easily accessible to animals allowed to graze in these areas. Although the entire plant is poisonous, the seeds contain the largest concentration of the poisonous principle. Most animals, however, refuse to eat the grain or screenings containing the seeds, and poisoning from browsing the leaves is usually mild.

Control

If roadside and pasture grasses are dry in late summer, animals should not be grazed in places where bouncing bet is abundant. The plant should be controlled because it is a nuisance as a weed as well as a danger to livestock.

Toxic Principles

The stems and leaves and, especially, the roots and seeds of bouncing bet contain a peculiar chemical substance known as a saponin that is undoubtedly the poisonous principle.

Clinical Signs

The poison irritates the digestive tract. Depending upon the amount eaten, an animal may exhibit the following signs: nausea, vomiting, rapid pulse, dizziness, and diarrhea. Depressed breathing has also been reported. Animals rarely die of bouncing-bet poisoning.

Treatment

Treatment is the same as that used to cure poisoning by corn cockle and cow cockle or cow-herb—the judicious use of digitalis, together with oils and demulcents given by mouth.

References

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Noxious/Invasive Species

Bracken (or Brake Fern)
(Poisonous Plant)

Illinois

Plant Characteristics

Pteridium aquilinum (L.) Kuhn, vars. latiusculum (Desv.) Underw., pseudocaudatum (Clute) Heller, and pubescens Underw.: Bracken is a typical fern with large fronds that grow up to 5 feet tall. The broadly triangular blades that terminate the erect, stiff, straw-colored stipes are 8 to 30 inches long, and are divided into 3 main parts, with each part bipinnately or tripinnately subdivided. Numerous fronds arise from the long, black, creeping rootstocks. For this reason, bracken usually grows in colonies. Spores are produced in specialized structures, the sori, that form a continuous line along the margins on the lower surfaces of the mature blades. Spores mature in late summer. In addition to spores, rootstocks also spread bracken.

Occurrence

Bracken is a plant of dry, sterile, sandy or stony soil of open woods and railroad trackways. The typical variety is grown in Europe and Africa. Three varieties occur in North America, with variety latiusculum (Desv.) Underw., ranging throughout much of the Midwest. The variety pseudocaudatum (Clute) Heller is chiefly found in the Coastal Plain, but its range extends northward in the interior to southern Ohio, southern Illinois, southern Missouri, and eastern Oklahoma. The third variety, pubescens Underw., has more western range, but occurs in South Dakota and Michigan.

Conditions of Poisoning

Bracken is usually the cause of poisoning in late summer when there is little pasture available. The plant is occasionally found in hay meadows; and since it retains its toxic principle even when in the dry state, it may be a problem during the winter months. Horses, sheep, and cattle have been poisoned by eating bracken. Clinical signs in horses differ greatly from those in cattle and sheep.

Control

Toxic Principles

The toxic principle has not been definitely identified, although in horses it has thiaminase activity.

Clinical Signs (Horses)

Loss of condition and weight and minor incoordination are observed when the horse is made to walk. It will not move unless forced, becomes lethargic, and stands with its feet apart in a crouched position with the back arched. If an attempt is made to turn the animal, it will usually cross its front legs. When forced to move, a severely affected horse will often develop extensive twitching of the muscles that progresses to severe tremors, and it may be unable to remain standing. The horse will frequently regain its feet only to undergo another series of tremors that almost reach the convulsive stage. It will usually stop eating or is prevented from eating by muscle twitchings and trembles. Marked cardiac irregularities occur, particularly a slow heartbeat.

Necropsy

No significant gross lesions characteristic of this disease are observed in horses on postmortem examination. A clinical pathological examination discloses marked lowering of the blood thiamine, increased pyruvate concentration, and a decrease in platelet count. In horses that have survived for a number of days after the onset of clinical signs, there is also a reduction in the red blood cells.

Treatment

Large doses of thiamine, 0.25 to 0.5 milligram per kilogram of body weight, are given intravenously. Some veterinarians recommend a comparable dose administered intramuscularly.

Clinical Signs (Ruminants)

Clinical signs in ruminants are sudden in onset, and death may occur in 4 to 8 days. Sheep are somewhat more resistant than cattle. Before severe clinical signs appear, the animals usually develop a rough hair coat and become listless. A mucous discharge from the nostrils may also be observed during this period. As the first severe clinical signs appear, the body temperature may become elevated, with readings as high as 109° F. There is rapid weight loss, dyspnea, salivation, bleeding from the nose, and congested or hemorrhagic mucous membranes and conjunctivae. In young cattle, edema in the throat region develops early. The clot-retraction procedure is an aid in diagnosing bracken poisoning. When blood from ruminants that have not been poisoned is collected in a clean glass tube and incubated at 37° C., the clot will retract and squeeze out the serum. This condition does not occur with blood from bracken-poisoned ruminants.

Necropsy

In typical cases of ruminants, almost every organ is splashed with hemorrhages varying from petechiae to ecchymoses. Ulcers are commonly found in the intestine, and occasionally in the abomasums. Bacteria may be isolated from the liver or other tissues. These appear to be secondary invaders, and fatalities have occurred in animals from which no pathogenic organisms have been recovered. Examination of the blood of a severely affected animal will reveal a marked reduction in the platelets, leucocytes, and red blood cells if hemorrhage has occurred, and examination will reveal hypoplasia of the bone marrow.

Treatment

Batyl alcohol supported by anti-infective agents, anti-heparin, and antihistamine therapy has reportedly given good results in bracken-poisoned ruminants. A blood transfusion often effects a dramatic improvement in the animal’s condition.

References

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Noxious/Invasive Species

Buffalo-bur
(Poisonous Plant)

Illinois

Description

Solanum rostratum Dunal: Buffalo-bur is an annual plant that grows up to 3 feet tall, with spiny, widely branched stems clothed with minute, branched or star-shaped hairs. The egg-shaped leaves are pinnately lobed, covered on both sides with hairs like those on the stem, and have prickles on the principal veins. The flowers are from ¾ to 1-¼ inches across, and have yellow petals and a spiny calyx. The berry, measuring up to ¼ inch in diameter, is clothed with numerous yellow spines.

Occurrence

Buffalo-bur is a native of the western plains, but has become an aggressive weed through most of the eastern and northern states.

Conditioning of Poising

Animals are likely to eat buffalo-bur plants if turned out to graze where these plants are abundant. The poisonousness of the plant apparently varies with the soil, climate, and other conditions. The berries, especially, become less poisonous as they mature, and the ripe berries are almost harmless. The poisoning of animals, then, is to be attributed to the browsing of foliage and green berries. Most cases of poisoning occur in sheep, goats, calves, pigs, chickens, and ducks.

Control

Animals should not be grazed in pastures infested with buffalo-bur. If the plant is mowed, dried, and burned as soon as blossoms appear, seeds will not be produced, and it will be easier to keep pastures from becoming heavily infested.

Toxic Principles

The toxic principle is solanine, a glycoalkaloid. When hydrolyzed, this compound yields several alkaloids.

Clinical Signs

The alkaloids, which are readily absorbed, are responsible for the major nervous signs. The clinical signs in a given case depend upon the balance between the irritant effect of the intact glycoalkaloid and the nervous effects of the released alkaloids. The irritant action of the solanine may vary in severity, causing anorexia, nausea, vomiting, abdominal pain and diarrhea. The effect on the nervous system causes apathy, drowsiness, dry mouth, labored breathing, trembling, progressive weakness or paralysis, prostration, and unconsciousness. The pupils are usually dilated. Death results from respiratory paralysis.

Necropsy

Variable degrees of inflammation ranging from hyperemia to hemorrhage to ulceration are found in the alimentary tracts. Edema in the perirenal tissues and ventral abdominal wall has been reported in some animals.

Treatment

Administration of a parasympathomimetic drug (pilocarpine) will usually relieve most of the clinical signs.

For a description and discussion of other solanum plants, see black nightshade and deadly nightshade, and potato.

References

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Noxious/Invasive Species

Buttercups (Pasture & Meadows)
(Poisonous Plant)

Illinois

Description

Cursed Crowfoot, Ranunculus sceleratus L.: Cursed crowfoot is an erect plant 4 to 24 inches tall, with smooth, hollow stems that are branched above and support many flowers. Basal and lower stem leaves are kidney-shaped and deeply 3-parted, with segments cleft again or lobed. Upper stem leaves are smaller, and commonly of 3 linear segments. The yellow petals, 1/8 inch long, are shorter than the green sepals. The numerous seeds, which develop when the flower withers, form short cylindrical heads.

Occurrence

Cursed crowfoot is a plant of marshes, ditches, and swampy meadows. It ranges from Newfoundland and Quebec to Alaska, south to Virginia, Kentucky, Missouri, New Mexico and California.

Description

Tall or Common Buttercup, Ranunculus acris L.: Tall buttercup is an erect herb, up to 3 feet tall, with smooth or hairy stems that are leafy below the middle. The rosette or basal leaves are stalked. The leaves are kidney-shaped in outline, and are deeply cleft into 3 segments that are in turn cleft into oblong or linear lobes. The flowers have deep-yellow (sometimes cream-colored) obovate petals that are 3/8 to 5/8 inch long – about twice the length of the sepals. The seeds are obliquely obovate and smooth, and have erect or curved beaks.

Occurrence

A native of Europe, tall buttercup was introduced into North America, where it has become naturalized from Labrador to Alaska, south to North Carolina, West Virginia, Ohio, Indiana, Illinois, Missouri, Kansas, and Oregon. In the northeastern states, it is a common weed of lawns, fields, roadsides, meadows, and clearings. In the Midwest, especially in Indian, Illinois, and Missouri, it occurs only along railroads or roadsides, and is not a common cause of poisoning among livestock.

Conditions of Poisoning

Buttercups usually inhabit moist areas. Animals allowed to graze in woods, in wet meadows, and by ditches and streams browse the buttercups with other succulent plants. All animals are susceptible to buttercup poisoning, but cows are most often poisoned. Dried buttercups are not poisonous, however, and buttercup-infested hay can be fed without danger.

Control

Animals should not be grazed in pastures heavily infested with buttercups, especially when other herbage is scant or dry. Buttercups are difficult to destroy because of their tendency to inhabit moist and wet places. Mowing the plants each year before they produce seed will keep them from increasing, and may eventually destroy them.

Toxic Principles

All known species of buttercups are poisonous. Cursed crow-foot, the most poisonous of our native species, contains anemonal, an acrid, volatile, very poisonous substance. Presumably, other buttercups contain the same or a similar substance in varying, usually lesser, amounts.

All species of livestock are susceptible to the toxic principle. In lactating cows there is a sharp drop in milk production, and the milk is bitter and red-tinted. Severe poisoning causes abdominal pain, diarrhea, nervousness, twitching of the ears and lips, labored breathing, partial paralysis, and convulsions. Sheep may collapse suddenly; pigs may show paralysis but only minor involvement of the digestive system.

Necropsy

Inflammation throughout the digestive system is the most significant lesion. In ruminants, there is usually extensive hyperemia in the abomasums and small intestine, with minor involvement of the large intestine.

Treatment

Demulcents or other agents to protect the stomach and intestine are recommended. There is no known antidote for the toxic principle.

Information Sources

For a description and discussion of hooked buttercup, small-flowered crowfoot, and swamp buttercup, which usually grow in wooded and old woodland pastures, see Buttercups for wooded areas fact sheet.

Cockleburs
Xanthium species. For a description and discussion of cockleburs, see that fact sheet.

References

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Noxious/Invasive Species

Buttercups (Woods)
(Poisonous Plant)

Illinois

Description

Hooked Buttercup
Ranunculus recurvatus Poir.: Hooked buttercup is an erect herb from 8 to 28 inches tall, with sparsely hairy, little-branched stems. The leaves are all stalked except the uppermost, and are broadly kidney-shaped or round. They are usually 3-cleft to below the middle, and are more or less clothed with hairs. The flowers have pale-yellow oblong petals approximately ¼ inch long that are about the same size as the sepals. The seeds have a firm hooked or coiled beak.

Occurrence

Hooked buttercup is a plant of moist or dry woods. It ranges from Quebec and Main to northern Minnesota, south to Oklahoma, Georgia, and Mississippi.

Description

Small-Flowered Crowfoot
Ranunculus abortivus L.:Small-flowered crowfoot is an erect plant from 4 to 20 inches tall, with smooth or slightly hairy stems that are branched above. The basal leaves are kidney-shaped to round, more or less heart-shaped at the bases, and round-toothed on the margins, although 1 or more of these leaves may be variously divided. The stem leaves are without stalks, or on very short stalks, and are deeply 3-parted to 5-parted. The segments are broadly linear and without teeth, or oblanceolatel or obovate and irregularly toothed. The flowers are quite small. The yellow diamond-shaped peals are less that 1/8 inch long, and are shorter that the green sepals. The numerous seeds form small, globose heads on the summit of the flower stalks when the flowers wither.

Occurrence

Small-flowered crowfoot is a plant of moist or dry woods, and ranges from Labrador to Alaska, south to Colorado, Florida and Texas.

Description

Swamp Buttercup
Ranunculus septentrionalis Poir.: Swamp buttercup is an erect or ascending plant when the first flower appears, but the stems then elongate, recurve to the ground, and root at the nodes. The basal leaves and principal stem leaves are similar. The blades are at least as broad as they are long, and are 3-parted, with the terminal segment stalked and the lateral segments either stalked or almost stalkless. The margins of the segments are variously toothed. The flowers have yellow obovate petals from 3/8 to 5/8 inches long.

Occurrence

Swamp buttercup is a plant of wet places in meadows, woods, low alluvial ground along streams, and in ravines and valleys. It ranges from Labrador to western Ontario, south to Virginia, Kentucky, Arkansas and Texas.

Conditions of Poisoning

Control

Toxic Principles

All known species of buttercups are more or less poisonous. Cursed crowfoot the most poisonous of our native species, contains anemonal, an acrid, volatile, very poisonous substance. Presumably, other buttercups contain the same or a similar substance in varying, usually lesser, amounts.

Clinical Signs

All species of livestock are susceptible to the toxic principle. In lactating cows there is a sharp drop in milk production, and the milk is bitter and red-tinted. Severe poisoning causes abdominal pain, diarrhea, nervousness, twitching of ears and lips, labored breathing, partial paralysis, and convulsions. Sheep may collapse suddenly: pigs may show paralysis but only minor involvement of rte digestive system.

Necropsy

Treatment

Demulcents or other agents to protect the stomach and intestine are recommended. There is no known antidote for the toxic principle.

References

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Noxious/Invasive Species

Climbing Bittersweet
(Poisonous Plant)

Illinois

Plant Characteristics

Celastrus scandens L.: Climbing bittersweet is a woody twiner with stems up to several yards long. These stems support alternately arranged, elliptical leaves and clusters of orange and scarlet fruits. The stems are green at first, but become gray by the end of the season. The leaves, 2 to 4 inches long, are long-pointed at the apices and round-toothed on the margins. The whitish or greenish flowers are disposed in terminal clusters from 1 to 3 inches long.

Occurrence

Climbing bittersweet is a common plant of woodlands and fencerows. Its fruits are widely scattered by birds, and the plant ranges from Quebec to Ontario, Manitoba, and Wyoming, south to Georgia, Alabama, Tennessee, Louisiana, Oklahoma, Texas, and New Mexico.

Conditions of Poisoning

Horses have occasionally been poisoned by eating climbing bittersweet leaves. Poisoning of sheep and cattle has also been reported.

Control

Although bittersweet poisoning is rare, the vine should be destroyed in all places where animals are grazed.

Toxic Principles

The toxic principle in climbing bittersweet is not definitely known, but it is thought to be the bitter substance euonymin.

Clinical Signs

Climbing bittersweet acts as a mild to severe purgative, and sometimes produces nausea and even prostration, depending upon the amount eaten. It also has a mild effect on the heart, somewhat like the effect of digitalis. The poisoning is not usually fatal.

Treatment

Move poisoned animals immediately to pasture where there is no climbing bittersweet. A veterinarian may administer other indicated treatment.

References

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Noxious/Invasive Species

Corn Cockle
(Poisonous Plant)

Illinois

Description

Agrostemma githago L.: Corn cockle is an erect, branched, silky stemmed annual herb that grows up to 3 feet tall. Its oppositely arranged, linear or lanceolate leaves are 3 to 5 inches long, smooth on the margins, and clothed with silky hairs. The red flowers are borne singely at the ends of the branches. The calyx lobes of the flowers are longer than the calyx tubes. A large seed capsule develops within each flower. This seed capsule contains many warty-covered dark-brown or black seeds that are about the size of a grain of wheat.

Occurrence

Corn cockle, a native of Europe, grows throughout most of North America. It is widely established weed of grainfields, roadsides, railroads, fallow fields, and waste places. Modern seed cleaning has reduced its abundance considerably.

Conditions of Poisoning

The green parts of corn cockle contain so little poison that animals can browse them freely without showing any ill effects. But the seeds are so poisonous that any animal may die from eating ¼ to 1 pound ground cockle seed per 100 pounds of body weight. Although unbroken seed contains as much poison as cracked or ground seed, it can be eaten in greater quantities without danger because the toxic principle is rarely released from the unbroken seed.

Cockle poisoning occurs most frequently among poultry, and is the result of feeding grain or screenings containing considerable quantities of whole and broken cockle seed. Sheep, cattle, and hogs may graze enough seed directly from plants to be poisoned, but most poisoning occurs from cockle infested grain or screenings. Among animals, pigs are the most easily poisoned. Human poisoning, now very rare, used to occur from eating bread made of flour ground from cockle-infested wheat.

Control

Remove corn cockle from pastures and grainfields, and use only seed that is free from corn cockle seed in planting grainfields. Do not feed screenings or grain that contains cockle seed in planted grainfields. Do not feed screenings or grain that contains cockle seed, and do not graze animals where corn cockle is growing.

Toxic Principles

The entire corn cockle plant, but especially the seed, contains a glucoside, githagin, and the saponin agrostemmic acid.

Clinical Signs

Although chronic corn-cockle poisoning may follow the eating of small amounts of corn cockle seed over a long period, acute poisoning from eating large amounts of the seed occurs more frequently. Some of the signs of corn cockle poisoning vary with different species of animals, but the following are common to all: colic, inability to stand, rapid breathing, and coma preceding death.

Pigs, the most susceptible of all animals to cockle poisoning, lie down with their snouts on the ground. Vomiting occurs, along with colic, diarrhea, and evacuation of foul-smelling, frothy fecal material. Spasms may precede death.

The first observable signs in cattle are nervousness, slobbering, and grinding of the teeth, followed by excitement, colic, and coughing lasting from 5 to 8 hours. Fetid diarrhea, rapid and noisy respiration, rapid and weak pulse, a progressive decline in temperature, and coma precede death. Death occurs about 24 hours after the onset of clinical signs. Corn cockle poisoning in horses begins with slobbering, yawning, colic, rapid, weak pulse and respiration, and ends in a coma and death. Cockle poisoning does not cause convulsions.

Necropsy

Hemorrhages on the heart and diaphragm and extensive congestion in the liver, kidneys, and spleen are constant findings in corn-cockle poisoning. The gall bladder and bile duct are edematous and contain scattered hemorrhages. Variable degrees of inflammation may be found in the stomach, with severe inflammation in the small intestine. Microscopic examination reveals congestion, hemorrhage, and necrosis of some cells in the liver. Hemorrhage and albuminous degeneration have been found in the kidneys.

Treatment

Any animal suspected of suffering from corn cockle poisoning should have immediate treatment. If a cockle poisoned animal is not properly treated, it is likely to die. Digitalis, a potent drug that should be administered only by a veterinarian, will counteract some of the poisonous effects of cockle. If given soon enough and in proper dosage, digitalis may save the poisoned animal. Oils and demulcents given by mouth have also been recommended.

References

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Noxious/Invasive Species

Great Lobelia or Blue Cardinal Flower
(Poisonous Plant)

Illinois

Description

Lobelia siphilitica L.: Great lobelia, or blue cardinal flower, is an erect, stout, sparsely branched perennial herb that grows to a height of 2 to 5 feet. The tall, angular stem is smooth or slightly hairy above, and supports alternately arranged, oval to lanceolate leaves that are 3 to 5 inches long, and have coarsely toothed margins. The numerous bright-blue flowers, about ¾ inch long, are crowded among numerous smaller leaves along the upper portion of the stem.

Occurrence

The great lobelia is a plant of swamps and wet ground from Main to Manitoba and Colorado, south to North Carolina, Alabama, and Texas.

Conditions of Poisoning

Animals browsing in moist places may eat the lobelia along with other plants. Only a few cases of animal poisoning have been attributed with certainty to the eating of the great lobelia.

Toxic Principles

The great lobelia, like other species of lobelia, contains the two alkaloids lobeline and lobelanine, as well as a volatile oil.

Clinical Signs

Since the alkaloids are identical with those of the Indian tobacco plant, the signs of poisoning are the same. Clinical signs include dilated pupils, salivation, nausea, vomiting, diarrhea, ulceration about the mouth and on the eyes, nasal discharge, and coma.

Necropsy

Lesions include ulcers in the mouth and on the cornea and edema of the conjunctiva. The stomach and intestine become severely inflamed, with hemorrhages in the muscle layers. Edema and congestion in the kidneys and fatty changes in the liver are also found.

Treatment

References

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Noxious/Invasive Species

Ground Ivy or Creeping-Charlie
(Poisonous Plant)

Illinois

Description

Glechoma hederacea L.: Ground ivy is a creeping perennial herb with slender, square stems that root at the joints. The oppositely arranged leaves are round or kidney-shaped, and have scalloped teeth on their margins. The small bluish flowers are found in the axils of the leaves, usually 3 per axil, and appear from April to June and sometimes into July.

Occurrence

A native of Eurasia, ground ivy has become thoroughly naturalized in North America as a plant of moist woods and as a troublesome weed of moist gardens and lawns. Ground ivy ranges from Newfoundland to Ontario, Minnesota, and North Dakota, south to Georgia, Alabama, Missouri, Kansas, and Colorado. It also occurs from Alaska to California.

Conditions of Poisoning

Ground-ivy poisoning is rare, probably because most animals do not like the bitter taste of the plant. Horses, the animal most often affected, are poisoned only after eating large quantities of the plant, either green or dried in hay.

Control

Animals should not be grazed in areas that are heavily infested with ground ivy, particularly when other herbage is dry or scarce, and hay should not be made in meadows where the plant is abundant. Ground ivy should be eradicated in all places where it is a danger to animals. It is easily destroyed by cultivation.

Toxic Principles

Like other members of the mint family, ground ivy contains a volatile, aromatic oil. It also contains a bitter substance of unknown chemical constitution. It is collected as a drug plant, and is used medicinally in small amounts as a stimulant and tonic.

Clinical Signs

After eating large amounts of ground ivy, poisoned animals, especially horses, slobber and sweat, and the pupils of their eyes become dilated. They pant for breath as if from over-stimulation. Poisoning from ground ivy is rarely fatal.

Treatment

Affected animals should be given feed that does not contain ground ivy. A veterinarian may administer other indicated treatment.

References

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Noxious/Invasive Species

Hemp or Marihuana
(Poisonous Plant)

Illinois

Description

Cannabis sativa L.: Hemp is a coarse, rough-stemmed annual herb that grows up to 9 feet high and resembles giant ragweed in general appearance. The palmately compound leaves are oppositely arranged on the lower part of the stem, but alternately arranged above. Each leaf has 5 to 9 long-pointed, narrowly lanceolate, coarsely toothed leaflets. The flowers are of two kinds—one bearing pollen, the other bearing seeds—but they do not occur on the same plant. Both kinds are small and greenish, and are borne at the tip of the stem and in the axils of the upper leaves.

Occurrence

Hemp, a native of Asia, is found as a weed along roadsides, railroads, and waste places. It is also a plant of sandy pasturelands and of moist soil of bottomlands and along drainage ditches. The distribution of hemp in the United States is peculiar. It has been reported from 39 of the contiguous states. Hemp is most common from Maine to Minnesota and South Dakota, south to Virginia, Missouri, and Kansas, with the greatest abundance in the Corn Belt.

Conditions of Poisoning

Since there have been few cases of animal poisoning from the eating of hemp, poisoning is to be suspected only when it is certain that the poisoned animal has eaten a considerable quantity of hemp and no other poisonous plant. Except in the seedling and younger stages, hemp is coarse and unpalatable. The poison is concentrated especially in the upper part of the mature plant as it flowers and produces seed. This part of the plant, if eaten in quantity, may produce narcotic signs and cause death.

Control

Hemp should be eradicated as soon as it makes its appearance. In August, 1969, Illinois classified hemp as a noxious weed under the Illinois Noxious Weed Law, and failure to eradicate the plant in that state can result in prosecution.

Toxic Principles

Hemp contains the alkaloid cannabidiol, the glucoside cannabinol, and the resin tetrahydrocannabinol. These poisonous substances occur in greatest abundance in the crude resin that is formed in the flowering part of the plant. Hemp seed is an important ingredient in bird-seed mixtures, and it is probably the small amounts of poisons in the seed that causes birds to sing more readily.

Clinical Signs

Hemp poisoning produces no clear-cut clinical signs. The signs that do appear are those of narcotic poisoning. The animal may at first appear highly nervous; later, it may give evidence of mental depression and derangement of the central nervous system. If death follows, it results from the depressing effect of the poison upon vital centers and organs.

Treatment

An animal suspected of being poisoned by hemp should be removed at once to a pasture in which no hemp is growing. If the animal appears to be severely poisoned, it should be placed under cover and restricted to a limited diet of hay or fresh forage, with plenty of water at hand. A veterinarian may be called to administer tannic acid and a stimulant.

References

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Noxious/Invasive Species

Hogwort
(Poisonous Plant)

Illinois

Description

Croton capitatus Michx.: Hogwort is an erect, stout, sparingly branched annual that grows up to 4 feet tall. The stem and the alternately arranged, narrowly oblong leaves are clothed with white, woolly hairs. The leaf margins lack teeth. The flowers are crowded at the ends of the branches, and are small, inconspicuous, and clothed with hairs. Some flowers have five sepals, five petals, and 10 to 14 stamens; others lack petals, have 5 to 10 sepals, and a single ovary with three styles that are divided 2 or 3 times so that there are 12 to 24 stigmas. Fruits produced from these flowers are capsules containing three seeds.

Occurrence

Hogwort is a plant of dry, sand, gravelly, or stony soil in orchards, fallow fields, roadsides, and railroad trackways. It ranges from Ohio to Indiana and Kansas, south to Florida and Texas.

Conditions of Poisoning

Hogwort has such a disagreeable taste that most animals will not eat it. For this reason, there are only a few reported cases of poisoning that can be attributed to browsing. Since the plant sometimes grows abundantly in pastures, however, it is sometimes cut with hay, and the hay can poison animals that eat it.

Control

Do not cut hay from pastures and fields in which hogwort plants are numerous. Destroy the plant in all places where animals graze.

Toxic Principles

Hogwort is believed to contain croton oil. This oil, besides being a powerful cathartic, can blister and irritate the skin. Pure croton oil is reportedly so poisonous that 10 drops of it will kill a dog.

Clinical Signs

Animals with skin irritations may be suffering from contact with hogwort. When animals eat hay that is infested with hogwort, they become nervous, show evidence of colic, and have diarrhea. Fatal poisoning by hogwort is rare.

Treatment

Treatment is largely directed toward easing the discomfort of the affected animal. Bland oils and sedatives are given when poisoning occurs from eating the plant.

References

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Noxious/Invasive Species

Horsetails and Scouring Rushes
(Poisonous Plant)

Illinois

Description

Equisetum species: Horsetails are small rush-like plants with jointed stems and whorled branches. The aerial stems, usually less than 3 feet tall, arise from much-branched underground stems called rhizomes. Aerial stems may be evergreen and perennial, or they may be annual and die at the frosts of autumn. Although the stems appear to be leafless, tiny leaves are found at the nodes or joints. They are fused on the margins but have free tips, and soon become blackish and scale-like. The number of leaves is the same as the number of ridges on the stem. Cones are borne at the tips of the stems. In the common horsetail (Equisetum arvense L.), there are two kinds of stems, sterile and fertile. The sterile stems are green and much-branched. Fertile stems, which appear in early spring, are brownish and support a single cone at the apex of each stem. These stems die after the spores are shed from the cones.

Occurrence

Horsetails grow in damp and wet places. The common horsetail also often grows in railroad ballast. It is a cosmopolitan plant found throughout most of the United States and Canada. Three other species occurring in the Midwest are reported to be poisonous. These are the tall scouring rush (Equisetum hyemale L.), smooth scouring rush (Equisetum laevigatum A. Br.), and marsh horsetail (Equisetum palustre L.). The tall scouring rush and smooth scouring rush are widespread in the Midwest. The marsh horsetail ranges from Quebec, Ontario, and Minnesota, south to Maine, Vermont, and Illinois. It also occurs from Alaska south to Montana and California. Some equisetums are called scouring rush because the stems contain silica, and were used by the pioneer women as a scouring material for cleaning pots and pans.

Conditions of Poisoning

Horsetails are troublesome as poisonous plants, especially when they are abundant in hay. There is some evidence that horses are less susceptible than sheep and cattle to the toxic principle in green plants. Equisetum palustre may be lethal to cattle, but Equisetum arvense is rarely if ever lethal. Horsetail poisoning in horses may be distinguished from bracken poisoning because animals poisoned with horsetails maintain their appetites even after clinical signs appear.

Toxic Principles

Extracts of equisetum possess thiaminase activity. Some authorities believe that the toxic principle in these plants also has other actions.

Clinical Signs

Animals poisoned by eating horsetails may die within a few hours after signs of poisoning appear, but they usually live several days or even weeks. Unthriftiness, excitability, loss of condition, staggering gait, rapid pulse, difficult breathing, diarrhea, and emaciation may be noted. Death is preceded by convulsions and coma. Lowered milk production in cows and trembling in sheep have also been observed.

Necropsy

Specific lesions caused by the toxic principle have never been reported.

Treatment

If horsetail poisoning is suspected, a change to uncontaminated hay should be made at once. Thiamine hydrochloride (0.25 to 0.5 milligram per kilogram of body weight) produces dramatic improvement in horses, but is less successful in relieving clinical signs in ruminants.

References

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Noxious/Invasive Species

Indian Tobacco & Pale Spiked Lobelia
(Poisonous Plant)

Illinois

Description

Lobelia inflate L.: Indian tobacco is an erect annual herb with a hairy, branched or unbranched stem up to 3 feet tall. The leaves are alternate, ovate, 1 to 33 inches long, and with toothed margins. They may be stalked or almost stalkless. Branches arise from the axils of the leaves. Racemes of pale blue or white flowers terminate the main stem and branches. Each flower is about ¼ inch long and 2-lipped, but has 5 petals and is subtended by a bract. The lowermost flowers have leaf-like bracts; the upper bracts are greatly reduced. The fruit is a small capsule embedded in the calyx tube that becomes inflated at maturity. Each capsule produces numerous tiny, yellow-brown seeds.

Lobelia spicata Lam.: Pale spiked lobelia is an erect perennial herb with a simple, smooth or slightly hairy stem up to 3 feet tall. It has alternate, lanceolate, oblanceolate, or obovate leaves up to 3 inches long, with scarcely toothed margins. The leaves are scattered on the stem, and form a rosette at the base of the stem. Upper leaves are gradually reduced to bracts. Slender racemes crowded with pale blue or white flowers terminate the stem. Each flower is about 3/8 inch long, and is subtended by a small bract. The calyx tube does not inflate in fruit.

Occurrence

Indian tobacco, ranging from Labrador to Saskatchewan, south to George, Alabama, Mississippi, Arkansas, and eastern Kansas, is found in open woods creekbanks, and pasturelands. It is sometimes a weed in gardens. Pale spiked lobelia is a plant of prairies, open woods, roadside ditches, railroad trackways, and pasturelands. It ranges from Quebec and New Brunswick to Saskatchewan, and south to Georgia and Arkansas.

Conditions of Poisoning

Cattle or sheep in pastures infested with Indian tobacco or pale spiked lobelia do not usually browse these plants except accidentally or when other plants are dry or in short supply. Nevertheless, in heavily infested pastures or during very dry periods, enough of the plants may be eaten to cause serious poisoning.

Toxic Principles

Indian tobacco, pale spikes lobelia, and other lobelias contain several alkaloids similar to nicotine in composition—among them lobeline and lobelanine—and a volatile oil.

Clinical Signs

Diagnosis is supported by evidence that the affected animal has browsed these plants in pasture, or by finding recognizable parts of the plants in the animal’s stomach. Clinical signs include dilated pupils, salivation, nausea, vomiting, diarrhea, ulceration about the mouth and on the eyes, nasal discharge, and coma. These signs are like those produced by an overdose of the alkaloid lobeline. Lobeline has been detected in the plants in a large enough quantity to account for poisoning.

Necropsy

Lesions include ulcers in the mouth, on the cornea, and in the intestine, and hemorrhage in the intestine and kidney cortex. Edema in the conjunctiva and kidneys and fatty changes in the liver are consistent findings.

Treatment

Atropine will relieve some of the clinical signs. A purgative may be administered if the animal shows signs of poisoning soon after eating the plants. Tannic acid given by mouth will combine with the toxic substances and delay absorption.

(for a description and discussion of great lobelia or blue cardinal flower, which is a plant of streams, ditches, ponds, springs, and swampy meadows, see “Great Lobelia.”)

References

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Noxious/Invasive Species

Oaks
(Poisonous Plant)

Illinois

Plant Characteristics

Quercus species: Oaks are easily recognized by their fruit, the acorn. Most oaks in the Midwest have broad blades that are shallowly to deeply cut or lobed on the margins. Some have rounded or blunt teeth or lobes, and are classed as white oaks; others have bristle tips on the teeth or lobes, and are classed as black oaks. Two species in the Midwest—the shingle oak (Quercus imbricaria Michs.) and the willow oak (Quercus phellos L.)—have leaves with margins that are not toothed or lobed, but entire. The shingle oak has leaves that are densely pubescent beneath.

Occurrence

Oaks are found in woodlands. Some species are restricted to dry, sandy soils; some to bluffs; some to uplands; and some to flood plain forests. Certain species have broad ranges while others have limited distribution. The shingle oak is common in parts of the Midwest. The willow oak, a Costal Plain species, has glabrous leaves, and is rare in the Midwest, found primarily in the extreme southern tip of Illinois and southeastern Missouri.

Conditions of Poisoning

Oak leaves emerge from the buds in early spring, and remain on the trees or on the ground below the trees through the fall and winter. Animals turned into woodlots to graze before grass becomes abundant may eat large quantities of the young leaves. Or, in seeking the young grass and other browse on the ground, they may eat quantities of old leaves with whatever else they can pick up. Small amounts of oak leaves do not seem to be injurious. But large amounts can cause severe illness, usually resulting in the death of the poisoned animal in a timeframe of two weeks to one month. In the Midwest, cattle and sheep are most often reported as suffering from oak poisoning, and the majority of cases occur in the early spring.

Control

The initial reaction to either acorns or leaves of oak trees appears to result from tannin. Later clinical signs are attributed to two toxic agents found in the leaves and in acorns—quercitrin and quercitin. Although the toxic principles are not readily water soluble, animals have been poisoned by drinking water in which oak leaves have soaked.

Clinical Signs

Anorexia, rumen stasis, constipation, rough hair coat, dry muzzle, evidence of abdominal pain, excessive thirst, and frequent urination are observed in ruminants. Feces are dry and dark-brown in color, followed by diarrhea that may be blood-tinged, and frequently there is edematous swelling in the ventral portions of the body. The pulse is rapid and weak, respirations are rapid and shallow, and there may be a brownish discharge from the nostrils. Lowered milk production in lactating animals follows subtoxic doses of acorns.

Necropsy

Gastritis and enteritis, with a bloody false mucoid membrane forming in the intestine, are typical. Increase peritoneal and plural fluids and petechiation on the subserous tissue, kidney, and heart are constant findings. Necrosis of the proximal tubules, abundant hyaline casts in the kidney, and necrosis of the liver are observed on microscopic examination.

Treatment

Supportive treatment and stimulants have been recommended. An oil-type laxative will help clear the intestinal tract and coat the inflamed mucosa. Blood transfusions, parenteral fluid, nutrient therapy, and glucocorticoids have been found helpful. Feeding calcium hydroxide reportedly prevents the development of signs of poisoning.

References

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Noxious/Invasive Species

Ohio Buckeye
(Poisonous Plant)

Illinois

Plant Characteristics

Aesculus glabra Willd.: The Ohio buckeye is a medium-sized tree that sometimes grows to heights of 70 feet but is usually shorter. The bark of young stems and branches is dark-brown and scaly; on old trunks, it is ashy gray, furrowed, and broken into plates. The oppositely arranged, palmately compound leaves have a slender petiole form 4 to6 inches long and 5 (rarely 7) obovate leaflets. The yellowish-green flowers are borne in large clusters at the ends of the branches, and appear in April or May after the leaves are expanded. The fruits are spiny-roughened, globular capsules that contain 1 to 3 large, glossy, chocolate-colored nuts, each with a whitish scar.

Occurrence

Ohio buckeye prefers the rich soil of river bottoms and banks of streams. It ranges from Pennsylvania to southern Michigan, southern Wisconsin, and eastern Nebraska, south to Alabama, Arkansas, and Oklahoma.

Conditions of Poisoning

Sprouts, leaves, and nuts of the Ohio buckeye have caused illness or death of cattle, sheep, and hogs when these animals were pastured where sprouts were present and where other forage was scarce. The young sprouts and the seeds are especially poisonous. Poisoning does not always follow when animals feed on the tree. In experimental feeding, signs of poisoning appeared in only a small number of animals.

Control

Until grass or other forage is abundant, animals should not be allowed to graze in woodland pastures where there are buckeye sprouts. Sprouts and seedlings should be grubbed out of pastures. If the trees are few, as they usually are, it may be advisable to collect the nuts to keep hogs from getting them. Ohio buckeye has little commercial value. Since the tree is uncommon, however, it should not be destroyed unnecessarily.

Toxic Principles

The poisonous principle in the Ohio buckeye is a narcotic alkaloid. It is apparently different from the glucosides aesculin and fraxin found in the bark of the European horse chestnut.

Clinical Signs

Ohio-buckeye poisoning affects the central nervous system. Prominent signs are an uneasy or staggering gait, weakness, severe trembling, and sometimes vomiting. Coma usually precedes death. Dilated pupils and congestion of the visible mucous membranes are commonly observed. Colic has been reported in poisoned horses.

Treatment

Poisoning caused by Ohio buckeye is rarely fatal, but a veterinarian should be called to give stimulants and purgatives.

References

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Noxious/Invasive Species

Pigweed
(Poisonous Plant)

Illinois

Description

Amaranthus retroflexus L.: Pigweed is an erect, branched, stout-stemmed annual herb that grows up to 7 feet tall. The stem, which is clothed with fine hairs, supports alternately arranged, egg-shaped leaves with long leaf stalks. The flowers are aggregated into terminal clusters of several to many short (2 to 8 inches long), ovoid, blunt, densely crowded spikes that terminate the stems but also arise form the upper leaf axils. The individual flowers are very small (1/4 inch long), lack petals, and are subtended by rigid, pointed bracts that are longer than the calyx. The fruit is a compressed, small, bladdery, 1-seeded structure less than 1/8 inch in diameter that opens along a circular line. The seeds are small (about 1/16 inch across), round, and dark red-brown.

Occurrence

A native of tropical America, pigweed ranges from Prince Edward Island, Canada, west to the Pacific Ocean, and south beyond the boarders of the United States.

Conditions of Poisoning

Pigs with continuous access to this plant rarely eat enough to be poisoned. But, when pigs raised in confinement are allowed to graze a pasture containing pigweed, they may become poisoned. The poisoning is not acute and the pigs may not show clinical signs until one week after exposure to the plant. About one-half of the animals will be affected. Mortality is usually low.

Toxic Principles

Nitrate and oxalate up to 30 percent or more expressed as oxalic acid have been found in pigweed. Although oxalate has not definitely been identified as the cause of the edema and clinical signs, it is suspect in this type of poisoning.

Clinical Signs

There is rapid onset of weakness, trembling, and incoordination 5 to 10 days after initial access to the weed. Soon there is knuckling of the pastern joints and almost complete paralysis of the pelvic limbs. Affected pigs usually maintain an attitude of sternal recumbency, followed by coma and death. If disturbed, they may drag themselves with the front legs. Edema in the caudal-ventral area of the abdomen is observed in most cases. The body temperature remains normal.

Necropsy

There is usually edema of the connective tissue around the kidneys, with considerable blood in the edema fluid, and edema of the ventral abdominal wall and perirectal area. The kidneys are normal in size and pale in color, with scattered areas of hyperemia extending into the cortex. Congestion and hemorrhage in the kidney cortex have been reported in a few cases.

Treatment

Remove animals from the source of the weeds. Medicinal treatment has not been found satisfactory.

References

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Noxious/Invasive Species

Potato
(Poisonous Plant)

Illinois

Description

Solanum tuberosum L.: The potato is a plant with weak, smooth or hairy stems that arise from a tuber. The odd-pinnate leave (4 to 10 inches long), has 3 or 4 pairs of pointed, egg-shaped leaflets, with numerous smaller leaflets standing between the larger ones. A few bluish-white flowers (1 to 1 ½ inches across), grow in clusters at the tips of long stalks. The fruits, which are infrequently produced, are yellowish or green globular berries about ¾ inch across.

Occurrence

Potato is a plant of the temperate belts of the Andes of South America. It is commonly cultivated in the United States, and occasionally escapes, persisting for only a year or two.

Conditions of Poisoning

Animals may browse potato plants or eat sprouted potatoes. The poisonousness of the plant apparently varies with the soil, climate, and other conditions. Most cases of poisoning occur in sheep, goats, calves, pigs, chickens, and ducks.

Control

Animals should not be grazed in pastures infested with potato plants. If the plant is mowed, dried, and burned as soon as blossoms appear, seeds will not be produced and it will be easier to keep pastures from becoming heavily infested.

Toxic Principles

The toxic principle is solanine, a glycoalkaloid. When hydrolyzed, this compound yields several alkaloids.

Clinical Signs

The alkaloids, which are readily absorbed, are responsible for the major nervous signs. The clinical signs in a given case depend upon the balance between the irritant effect of the intact glycoalkaloid and the nervous effects of the released alkaloids. The irritant action of the solanine may vary in severity, causing anorexia, nausea, vomiting, abdominal pain, and diarrhea. The effect on the nervous system causes apathy, drowsiness, dry mouth, labored breathing, trembling, progressive weakness or paralysis, prostration, and unconsciousness. The pupils are usually dilated. Death results from respiratory paralysis.

Necropsy

Variable degrees of inflammation ranging from hyperemia to hemorrhage and ulceration are found in the alimentary tract. Edema in the perirenal tissues and ventral abdominal wall has been reported in some animals.

Treatment

Administration of a parasympathomimetic drug (pilocarpine) will usually relieve most of the clinical signs.

References

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Noxious/Invasive Species

Rocket Larkspur
(Poisonous Plant)

Illinois

Description

Delphinium ajacis L.: Rocket larkspur is a branching annual from 12 to 28 inches tall, with alternately arranged leaves that are deeply dissected into narrowly linear segments. The flowers, ¾ to 1-½ inches wide, are disposed in racemes, and have blue, violet, pink or white petals united into a single spur. Each flower produces a follicle ½ to ¾ inch long.

Occurrence

A native of Europe, rocket larkspur has escaped from gardens in North America. It ranges from Nova Scotia to Minnesota and Montana, south to South Carolina and Texas.

Conditions of Poisoning

The toxicity of larkspur plants under natural conditions depends upon seasonal variations in the amount of toxic principle, the species of animal, and the parts of the plant consumed. Although the minimum lethal dosage (MLD) of rocket larkspur has never been accurately determined for domestic animals, apparently an animal will be poisoned if it eats 0.5 percent of its body weight of the plant. The toxicity seems to be reduced as the plant reaches maturity. The seeds are quite toxic, however, and are often the cause of poisoning late in the growing season. For unknown reasons, sheep are much less susceptible than cattle and horses to the toxic action of the larkspur.

Toxic Principles

The poisonous principle in larkspur is a combination of diterpenoid alkaloids. Some of these alkaloids, of which delphinine is a major one, have been identified, and structural formulas are known.

Clinical Signs

The diterpenoid alkaloids seem to affect the central nervous system, and the poisoned animal will appear weak. The animal is uneasy at first, and then exhibits stiffness of gait and a characteristic straddles stance with the hind legs held far apart as though to prop up the body. There is usually twitching of the muscles, especially those of the muzzle, shoulder, flank, and hip. While the animal is standing, the back is arched. Occasionally, the animal will collapse when it attempts to walk backward. A severely poisoned animal will collapse suddenly; a less severely poisoned animal usually rests on its sternum with its head on the ground. In certain cases, the head may remain erect.

Immediately after collapsing, the animal frequently tries to regain its footing. It will often succeed in standing, but signs of weakness returns, and it collapses again. Excitement intensifies the clinical signs. Nausea, vomiting, and evidence of abdominal pain have been reported in pigs. During vomition, ingesta may be drawn into the trachea, and the animal suffocates. In other cases, fatalities result from respiratory paralysis. The pulse and respiration are rapid and weak throughout the course of clinical signs. All animals poisoned with larkspur become constipated, and relief of this condition may hasten recovery. Bloating frequently occurs in ruminants.

Necropsy

There are no diagnostic lesions produced by larkspur poisoning. Congestion of the internal blood vessels and various stages of irritation of the mucosa of the alimentary tract are practically the only findings observed.

Treatment

The following prescription has been recommended: physostigmine, 1 grain; pilocarpine, 2 grains; strychnine, ½ grain. These drugs are dissolved in 20 milliliters of water and administered subcutaneously for each 500 pounds of body weight. Sheep require about ¼ of this dosage.

References

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Noxious/Invasive Species

Sneezeweeds
(Poisonous Plant)

Illinois

Description

Helenium Autumnale is an erect, fibrous-rooted perennial with glabrous or finely pubescent stems that grow up to 5 feet tall. The stems support numerous lance-linear to narrowly egg-shaped leaves that are 2 to 6 inches long. The leaves are narrowed to stalkless bases that extend downward on the stems as greenish wings. The several to many flowering heads are disposed in leafy inflorescences. Each head, hemispheric or subglobose in shape, has a yellow disk from 3/8 to ¾ inch across and 10 to 20 yellow rays from 3/8 to 1 inch long.

Helenium flexuosum Raf. Is an erect, fibrous rooted perennial with more or less pubescent stems that grow 4 feet tall, and are winged by the decurrent leaf bases. The lowermost leaves are oblanceolate in outline, and are soon deciduous; other leaves are oblong or lanceolate and more persistent. The flowering heads are in open, bracted inflorescences. Each head has a purple or brownish-purple disk from ¼ to ½ inch across and yellow rays from ¼ to ¾ inch long.

Helenium amarum (Raf.) H. Rock is a glabrous, glandular-dotted annual plant with stems from 8 to 20 inches tall. The stems support numerous linear leaves that are 1/16 inch wide. The flowering heads stand on short, naked peduncles that extend beyond the leafy part of the plant. Each head has a yellow disk from ¼ to 3/8 inch across and 5 to 10 yellow rays from ¼ to 3/8 inch long that produce achenes.

Occurrence

Helenium autumnale grows in moist, low ground, especially along streams, from Quebec to British Columbia, and south to Florida and Arizona. Helenium flexuosum Raf. grows in moist, low ground from Maine to Michigan, and in southern Illinois and southern Missouri, south Florida and Texas. Helenium amarum (Raf.) H. Rock is a plant of prairies, open woods, fields, and waste places. It ranges from Virginia, Missouri, and Kansas, south to Florida, Texas, and Mexico, and is apparently spreading northward.

Conditions of Poisoning

Since sneezeweeds are bitter and sharp-tasting, most animals avoid them. But some animals, usually cows and sheep, develop a taste for sneezeweeds, and will eat large quantities. Although all parts of the plant are poisonous, the blossoms are the most dangerous. For this reason, most of the cases of serious poisoning occur in the late summer and early fall. Sneezeweeds may also cause cows to give bitter milk. The plants remain toxic when dried.

Toxic Principles

The exact nature of the poison has not been determined. It appears to be the glucoside dugaldin.

Clinical Signs

The usual signs of sneezeweed poisoning are rapid pulse, restlessness, difficult breathing, staggering, loss of muscular control, and extreme sensitivity to touch. After eating large quantities of sneezeweed blossoms, animals may die suddenly. Spasms and convulsions may precede death.

Necropsy

Gastrointestinal irritation, engorgement of the liver and kidney, and large necrotic areas in the lungs are lesions observed in most animals fatally poisoned by sneezeweed.

Treatment

If animals give bitter milk or show other mild clinical signs of sneezeweed poisoning, they should be removed at once to pastures where they will not have access to sneezeweed. Melted lard, if given before the spasms begin, will offset the action of the poison. A veterinarian may administer other indicated treatment.

References

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Noxious/Invasive Species

Star-of-Bethlehem
(Poisonous Plant)

Illinois

Description

Ornithogalum umbellatum L.: Star-of-Bethlehem is a plant with a leafless stalk that is 4 to 12 inches tall and several very narrow, channeled leaves that arise from a bulb. Three to 7 flower stalks grow from the leafless stem, and each stalk supports a single flower that is 3/8 to ¾ inch long, with 6 segments that are white above and have a broad green stripe beneath. The fruits are capsules containing a few dark, roundish seeds.

Occurrence

A native of Europe, star-of-Bethlehem was cultivated in gardens in North America, and has escaped to fields and roadsides. It is naturalized from Newfoundland to Ontario and Nebraska, south to Mississippi, Missouri, and Kansas.

Conditions of Poisoning

Poisoning occurs only when the bulbs are brought to the surface by frost-heaving, plowing, or rooting by swine.

Toxic Principles

Although the toxic principle has not been definitely identified, it appears to be similar to the alkaloid colchicines. It seems to be present only in the white onion-like bulbs.

Clinical Signs

The clinical signs are depression, salivation, bloating in ruminants, vomiting, diarrhea, labored breathing, rapid pulse, and bloody urine. Death results from respiratory failure.

Necropsy

Extensive gastroenteritis and hemorrhage in the kidney are the significant lesions. Blood may be found in the intestines.

Treatment

Because of the extensive loss of body fluids and electrolytes, therapy for the hypovolemic shock-like state is indicated. Blood transfusion and parenteral administration of electrolyte solutions are recommended. There is no antidote for the toxin.

References

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Noxious/Invasive Species

Water Hemlock
(Poisonous Plant)

Illinois

Description

Cicuta maculate L. Water hemlock is an erect, stout, much-branched, leafy herb that grows up to 7 feet tall, with stems arising from tuberous-thickened roots. The alternately arranged leaves, often 1 foot in length, are bipinnately or tripinnately compound, and have completely separated leaflets. The bases of the leaf stalks clasp the stems. The leaflets are from 1 to 4 inches long, and are linear or lance-ovate, with margins that are usually sharply and coarsely serrate. The primary lateral veins from the midvein are directed to the sinuses. Flowers are disposed in umbrella-like clusters called umbels. The umbels are numerous, 2 to 5 inches wide, and surpass the leafy shoots.

This species can be easily identified by two of its characteristics. (1) The primary lateral veins in the leaflets end in the sinuses or notches between the teeth, not in the tips of the teeth. Secondary or weak veins may branch from the primary veins near the sinuses and end in the teeth, but these veins are readily distinguished from the primary ones. (2) The otherwise hollow central cavity at the base of each stem is crossed by horizontal plants of pith. This characteristic can be seen by slicing the base of the stem lengthwise with a knife.

Occurrence

Water hemlock grows in swamps, marshes, ditches, and wet depressions in prairies and meadows from Quebec to Minnesota and Manitoba, south to North Carolina, Tennessee, Missouri, Oklahoma, and Texas. It sprouts from the tuberous-thickened roots in early spring, and flowers from June to August.

Conditions of Poisoning

Water hemlock is one of the most poisonous plants to livestock. The flowers, seeds, and mature leaves are not toxic in either the green or dried state; but a relatively small amount of the tuber, which contains the toxic principle, may fatally poison an animal within less than 1 hour after being consumed. The young sprouts also contain the toxin.
Since the toxic principle is mainly contained in the tuberous roots, poisoning usually occurs in the spring when the soil is moist. In grazing the early growth of the plant, animals, especially cattle, may pull up the roots along with other parts of the plant. After the plants bloom, the quantity of the toxic principle in the roots is decreased.

Toxic Principles

The toxic principle is cicutoxin, a resinous, thick, yellow liquid with a carrot-like odor. The young leaves are nearly as toxic as the roots. Two ounces of the young leaves, stems, or tubers have been known to fatally poison sheep. Eight to 10 ounces will fatally poison a mature cow or horse. It is estimated that 1 ounce of the tubers will kill a pig.

Clinical Signs

The toxic principle is irritating, and occasionally pigs will vomit after eating the tubers. In all species, clinical signs develop rapidly. These are salivation, twitching of the muscles, champing of the jaws, grinding of the teeth, and evidence of pain, followed by muscular spasms and convulsions. Running fits and convulsions continue when the animal is recumbent. The body temperature may be elevated, resulting in coma. Death is caused by respiratory paralysis and asphyxia, and may occur within 30 minutes after ingestion of the plant. In general, the clinical signs produced by this toxin are similar to those produced by picrotoxin.

Necropsy

Congestion and hemorrhage in the viscera, enteritis, and yellow discoloration of the fat are found in chronic poisoning. Acutely poisoned animals may not show any characteristic lesions.

Treatment

A central-nervous-system depressant is used to overcome the stimulant effect of cicutoxin. If the poisoned animal survives for 5 to 6 hours, it will usually recover and show no further effect from the toxins.

References

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Noxious/Invasive Species

White Sweet Clover
(Poisonous Plant)

Illinois

Description

Melilotus alba Desr.: White sweet clover is an erect, slender, branched biennial herb from 3 to 9 feet tall. The clover-like leaves are made up of three oblong leaflets that are ½ to 1 inch long. The small, fragrant white flowers appear in numerous slender clusters that arise from the axils of the leaves. The fruits are ovoid, smooth pods that contain 1 to 4 seeds.

Occurrence

A native of Eurasia, white sweet clover was introduced into North America, where it has escaped cultivation to become established along roadsides, in railroad trackways, and in waste places. It occurs throughout the United States and much of Canada. The yellow sweet clover (elilotus officinalis (L.) Lam.) is similar to white sweet clover, except that the flowers are yellow. It grows from Quebec to British Columbia, and south beyond the borders of the United States.

Conditions of Poisoning

Sweet clover, a valuable forage crop, may be used freely as pasture, but the feeding of damaged or spoiled sweet-clover hay or silage may cause the death of cattle. The damaged hay is usually moldy, but not all moldy hay is poisonous. Sweet-clover poisoning usually occurs in winter, and does not become apparent until the animal has been fed damaged sweet clover for 2 weeks or more. Cattle are the most frequently poisoned of all animals.

Control

Moldy sweet-clover hay or silage should be fed with other kinds of hay, alternating the sweet clover and the other hay at 2-week intervals.

Toxic Principles

The poisonous principle coumarin has been isolated and crystallized from damaged sweet clover. This crystalline substance can be used to reproduce the disease in susceptible rabbits. The exact action of the toxic substance is unknown, but its prominent effect is interference with the clotting of the blood as a result of a depression of the prothrombin level and certain other conditions essential for coagulation of blood.

Clinical Signs

The poisoned animal may be dull and stiff and reluctant to move. Marked swellings may occur on any part of the body, but are most common in the hip, shoulder, neck, and chest regions. The swellings are doughy and contain blood. When hemorrhages are extensive, the mucous membranes are pale, the pulse and respiration are rapid, and the animal becomes very weak. Animals may bleed to death even from such minor operations as dehorning or castration. Examination of the blood reveals a loss of red blood cells, a decrease in hemoglobin, and delayed clotting time. Death may occur suddenly or after several days.

Necropsy

Extensive localized hemorrhage or diffuse hemorrhage in many tissues are constant findings in sweet-clover poisoning.

Treatment

Treatment consists of blood transfusions or the intravenous injection of defibrinated or citrated blood from a normal animal. Blood-clotting powers are restored in less than one hour, and complete recovery occurs in 7 to 14 days, provided that the animal is not allowed to eat any damaged sweet clover.

References

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Noxious/Invasive Species

Wild Cherries
(Poisonous Plant)

Illinois

Description

Chokecherry, Prunus virginiana L.: Chokecherry is a small tree or shrub with oblong to obovate leaves. The leaves are sharply toothed, and the teeth are slender and ascending. The flowers are produced in long, many-flowered clusters. The fruit is scarcely edible.

Occurrence

Chokecherry grows in a wide variety of habitats from Newfoundland to Manitoba, south to Virginia, Kentucky, Arkansas, and possibly farther south.

Description

Pin Cherry, Prunus pensylvanica L. f.: Pin cherry is a shrub or small tree with lanceolate leaves and flowers disposed in few-flowered clusters. It grows in dry or moist woods and in recent burns and openings.

Occurrence

Pin cherry ranges from Newfoundland to eastern British Columbia, south to New Jersey, western Virginia, northern Indiana, northern Illinois, South Dakota, and Colorado.

Description

Wild Black Cherry, Prunus serotina Ehrh.: Wild black cherry is a medium-sized tree that grows up to 60 feet in height. Its furrowed bark forms persistent, recurved scales on the trunk. The almost horizontal branches are smooth and red-brown. The alternately arranged, oblong leaves, 2 to 6 inches long, are abruptly pointed at the apices, wedge-shaped or acute at the bases, and finely toothed on the margins. The midvein beneath is usually clothed with a rusty pubescence. The white flowers appear with the leaves, and are borne in many-flowered clusters from 4 to 6 inches long. The fruits are globular, purplish-black or black edible cherries that ripen from July to September.

Occurrance

Wild black cherry ranges from Nova Scotia to North Dakota, south to Florida and Texas. It is common in fencerows, along roadsides, and in thickets and open woods. Birds greedily devour the fruit, and are largely responsible for the spread of the tree.

Conditions of Poisoning

Animals often eat wild-cherry leaves directly from the tree, from branches that have been cut or broken from the tree, or in dried hay. The leaves are poisonous under all these conditions.

Control

Keep animals from grazing where they can browse wild-cherry leaves.

Toxic Principles

Wild cherries, like bitter almond, contain a cyanogenetic material, the glucoside amygdalin. Amygdalin itself is not especially poisonous, but it is broken down by hydrolysis into the toxic hydrocyanic or prussic acid. The acid is formed quickly from bruised cherry leaves. This phenomenon can be observed by crushing several leaves in the hand and then smelling the strong cyanide odor. Johnsongrass, sudangrass, and sorghum may also be sources of prussic acid.

Clinical Signs

The animal is apprehensive, its respirations are rapid and soon become labored, and it attempts to breathe through its mouth. Muscle weakness and spasms, staggering, convulsions, and coma are usually observed within 10 to 20 minutes after the onset of signs. Respirations become shallow and then cease, although the heart may continue to beat for several minutes after breathing stops. Death results from internal asphyxiation that affects all systems of the body, especially the respiratory centers.

Necropsy

In acute poisoning, the venous blood is usually dark red, although it may be bright red. There is often great reduction in cardiac output, but the peripheral tissues continue to utilize some oxygen. The blood becomes dark red from accumulated carbon dioxide and clots slowly.

Lesions are congestion of the liver and distension of the venous system, and congestion and hemorrhage in the trachea and lungs and on serous membrane surfaces. The rumen may be distended with gas. The odor of bitter almonds may be detected on the newly opened cadaver. If the dose is low and death is delayed, there will be inflammation in the stomach and small intestine. Large doses of hydrocyanic acid prolong preservation of the carcass.

Treatment

Any animal suspected of being poisoned by wild cherries should be treated immediately by a veterinarian, since death may occur within a few minutes or a few hours. Treatment for prussic-acid poisoning is directed toward an immediate relief of the toxic effects. Intravenous or intraperitoneal injection of a solution containing sodium thiosulfate and sodium nitrite brings prompt relief. Commercial solutions are available containing these two drugs as well as methylene blue. Methylene blue stabilizes the other two drugs in solution.

An intravenous injection of a solution of methylene blue alone is also effective. Success depends upon prompt treatment and the amount of prussic acid freed in the body. Giving corn syrup by mouth may reduce the rate at which the prussic acid is released. The same treatment is used for prussic-acid poisoning caused by Johnsongrass, sudangrass, and sorghum.

References

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Noxious/Invasive Species

Yews
(Poisonous Plant)

Illinois

Description

Taxus species: Yews are evergreen trees or shrubs with spirally arranged, linear, dark-green leaves that spread in two ranks, and with small, inconspicuous flowers and showy, berry-like red or yellow fruits. The bark is thin, reddish or reddish-brown, and flaking in thin scales. Winter buds have overlapping scales. The linear leaves are 1 to 1-½ inches long, have a prominent midvein and 2 yellowish-green bands on the under surface, and lack resin ducts. They may be abruptly pointed or gradually long-pointed at the apex.

Yews are northern hemisphere plants, usually separated into 7 or 8 species with numerous named cultivars or varieties. Two species are native to North America, the Canada yew (Taxus Canadensis Marshall), and western yew (Taxus brevifolia Nutt.). Canada yew is a shrub, less than 5 feet tall, with seeds that are broader than they are high. Western yew is a small tree with ovoid, 2- to 4-angled seeds.

Occurrence

Canada yew, a plant of coniferous woods, bogs, stony deciduous forests, and cliffs, ranges from Newfoundland to Quebec and Manitoba, south to Virginia, Kentucky, Ohio, Indiana, Illinois, and Iowa. Western yew usually grows singly or in small groups on deep soils along streams and on moist flats near the coast. It occurs along the coast from Alaska and British Columbia, south to California, and eastward to Montana.

Several other species of yews are cultivated in the United States. These include the English yew (Taxus baccata L.) and the Japanese yew (Taxus cuspidate Sieb. and Zucc.). The English yew is a native of Europe, North Africa, and western Asia. The leaves are gradually pointed, and the winter bud scales are obtuse. This species and its numerous cultivars are grown as ornamentals.

The Japanese yew, a native of Japan, Manchuria, and Korea, is widely used as an ornamental. Like Canada yew, it has winter bud scales with acute tips and abruptly pointed leaves. The leaves of Japanese yew are wider than those of Canada yew. Some of the common cultivars are Brown’s yew (Taxus cuspidate ‘browni’) and Taxus cuspidate ‘capitata.’

Taxus X media Rehder is a presumed hybrid between the English yew and the Japanese yew. Two of its important cultivars are Hick’s yew and Hatfield yew.

Conditions of Poisoning

Yews are among the most toxic plants. They appear to be poisonous all seasons of the year, although most cases of poisoning have been reported in the spring or summer when the trees have been trimmed and cuttings have been placed where animals have access to them. If the clippings or plant itself are burned, the ashes are still poisonous. Thus don’t allow the livestock access to any form or part of the plant or its products.

Toxic Principles

The toxic principle is taxine. Foliage, bark, or seeds, whether dry or green, are toxic to people and to all classes of livestock.

Clinical Signs

The sudden onset of bradycardia, nervousness, trembling, dyspnea, incoordination, and collapse represents characteristic poisoning by these trees. Gastroenteritis may be present in subacute cases. Death results from cardiac failure. The mechanism of the depressing action of the toxic agent on the heart is unknown.

Necropsy

There are usually no lesions found in animals with acute yew poisoning. In subacute poisoning, mild inflammation may be present in the anterior portion of the intestine. This inflammation appears to be caused by an irritating oil and not by taxine.

Treatment

Atropine sulfate has been reported of value in treating animals suffering from subacute poisoning. No effective treatment has been reported for acute poisoning.

References

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