Reining in the Formosan subterranean termite, an East Asian pest now established in 13 states, is the goal of a new ARS-led national campaign. Scientists suspect the termite entered the United States via supply ships shortly after World War II. But it wasn't until the late 1960's that scientists detected it in New Orleans and other southern port cities. Today, the wood-eating pest costs $1 billion annually in repairs and control measures. A U.S. Environmental Protection Agency ban in the late 1980's of potent chemicals called organochlorines has exacerbated the problem. The ban stemmed from concerns over toxic residues posing a danger to human and environmental health. Scientists fear the Formosan subterranean termite will continue its spread. ARS researchers in New Orleans are coordinating a large counterattack called "Operation Full Stop." It includes experts from other ARS labs, the New Orleans Mosquito and Termite Control Board, the Audubon Institute and collaborating universities such as Louisiana State University. They'll employ an arsenal of weapons to reduce the termite's numbers and its colonies. These include slow-acting toxic baits, computerized maps, growth-regulating compounds and biocontrol agents such as predatory insects and fungi. The campaign began in New Orleans but will eventually expand to other infested cities and states.
Southern Regional Research Center, New Orleans, LA
John Patrick Jordan/Alan Lax, (504) 286-4212, pjordan@nola.srrc.usda.gov/alax@nola.srrc.usda.gov

Newly isolated genes that produce protective proteins in plants are now in gene banks for public use. ARS scientists worked for 6 years to identify and purify these plant protective proteins in citrus. These proteins help plants defend themselves by warding off attacks by pests or disease. Although many plants already have genes that produce protective compounds, it would be useful to have transgenic plants express the compounds in larger quantities or at a different place in the plant at a different time. With funds from a self-imposed grower tax, the Florida Citrus Production Research Advisory Council supports ARS research to study plant defenses. If plants can better defend themselves, growers will spend less on fungicides and insecticides, also benefitting the environment.
U.S. Horticultural Research Laboratory, Orlando, FL
Hamed Doostdar, (407) 897-7300, doostdar@asrr.arsusda.gov

New microencapsulation technology could help viruses, bacteria and other environmentally friendly biopesticides compete with traditional chemicals. Into cornstarch that was heated, or partially gelatinized, scientists mixed microbes such as the bacterium Bacillusthuringiensis (Bt) or baculoviruses--a group of viruses that cause disease in caterpillars. When the mixture was added to water and dried, the microbes became entrapped in tiny particles that could be resuspended in water and sprayed on crops. Until now, marketing encapsulated biopesticide technology has been impeded because there was no single formulation appropriate for different crops and field-spraying equipment. The amount of ingredients such as sun protectants added to boost a formulation's effectiveness depended on how much water was needed for the mix. With the new technology these ingredients, called adjuvants, are mixed into formulations as they are manufactured. The adjuvants are uniformly bonded with starch and the biopesticide and remain in a stable blend throughout conventional tank mixing and application.
National Center for Agricultural Utilization Research, Peoria, IL
Michael R. McGuire, (309) 681-6595, mcguirmr@mail.ncaur.usda.gov

A device used to quickly separate dirt, sticks and stems from farm seeds may simplify and cut the cost of another job--insectary mass-rearing of beneficial wasps for outdoor biological control assignments. The helpful wasps, harmless to humans, parasitize crop pests such as the Mediterranean fruit fly. Medfly can attack more than 400 different crops worldwide. ARS researchers in Hawaii showed that a seed-sorting pneumatic air separator can quickly sort immature fruit flies that harbor a living wasp from those that do not. The sorting can be done when the fruit fly is still inside its pupal case and resembles a tightly rolled, dried-up leaf. The wasp develops inside the fruit fly pupa, eventually kills it, and then emerges from the pupal case. When released outdoors, adult female wasps parasitize new fruit fly victims by injecting eggs into the hapless pupae. In tests with about 150,000 pupae of medfly, oriental fruit fly and melon fly, researchers showed that the separator's airstream lifts lighter, parasitized fruit fly pupae into an upper tray, while denser, unparasitized pupae drop into a lower tray. Scientists used three different species of beneficial wasps in the tests.
Tropical Fruit, Vegetable, and Ornamental Crop Research Laboratory, Hilo, HI
Harvey T. Chan, (808) 959-4300, hchan@aloha.net

Controlling Cape ivy, a weed rapidly taking over natural areas along the west coast of the U.S., is the goal of a new cooperative project between ARS and South African scientists. The vine was introduced from South Africa as an ornamental plant before the turn of the century. Now it has spread into wild areas throughout coastal California and into Oregon, where there are no natural enemies to curb the weed's growth. Cape ivy reduces native plant diversity and precious habitat that endangered plants and animals need. Chemical weed killer is frequently not a control option because the weed grows in hard-to-reach areas, near water and in areas that contain sensitive species. The researchers hope to implement a biological control solution. The Pretoria scientists began searching this spring along the east coast of South Africa for insects and pathogens that appear to control the ivy naturally. The researchers believe such biocontrols exist because Cape ivy is uncommon in its homeland, suggesting that natural enemies keep it in check. Once potential biological agents are found, ARS will test them for safety on native U.S. plants. Ultimately, if an effective biocontrol is identified, ARS will apply for permission to release the insect or pathogen.
Plant Protection Research Unit, Albany, CA
Joe Balciunas, (510) 559-5975, joebalci@pw.usda.gov

A new genetic fingerprinting technique could be sweet news for sugarcane growers looking for ways to put the brakes on ratoon stunting disease (RSD) in sugarcane. ARS researchers devised the technique to help growers avoid planting fields with seedpieces or cuttings infected by Clavibacter xyli subsp. xyli, the bacterium that causes RSD. Key to the approach is polymerase chain reaction, or PCR. It locks onto specific bacterial genes in infected plant samples and then mass-produces the genes so they can be identified or fingerprinted. If the sample is clean, no chain reaction occurs. The RSD bacterium is responsible for one of the most serious diseases of sugarcane in Florida and Louisiana, where much of the nation's $1.5 billion crop is grown. Severe outbreaks can cause a 50 percent drop in a crop's sucrose yield. This usually happens in the second or ratoon crop, where plants grown from cuttings of a previous harvest lose their vigor and reach half their normal height. RSD doesn't produce any visible symptoms other than stunted growth, so the new diagnostic test should prove handy to growers who currently have no way of knowing their crop is infected until late in the season.
Sugarcane Research Unit, Southern Regional Research Center, New Orleans, LA
Yong-Bao Pan (504) 853-3165, ypan@nola.srrc.usda.gov

Two recent advances could reduce citrus-growing risks. In certain citrus varieties, ARS scientists have identified a gene that appears to give the plants resistance to Phytophthora, a devastating fungal pathogen that causes foot rot. Most of the best citrus varieties are sweet oranges whose roots are highly susceptible to foot rot, so they must be grafted and grown on more resistant rootstocks. Many commercial rootstocks are also very susceptible to Phytophthora. Rootstocks are used to increase yield, tolerance to different soil types and resistance to other diseases. The research goal: put the newly isolated gene into a sweet orange like Valencia to see if it can be grown on its own roots and still resist Phytophthora. Meanwhile, the researchers have also identified proteins that disrupt feeding of the West Indies sugarcane rootstalk borer weevil. This pest teams up with Phytophthora to land a powerful one-two punch on citrus. Weevil larvae feed on roots, causing plant decline and death. Injured roots are more susceptible to Phytophthora. The newly identified proteins not only block certain key enzymes the weevil larvae need to break down plant cells, but they also work well on fungal pathogen enzymes. Researchers are looking into ways the proteins can be used to control the weevil.
U.S. Horticultural Research Laboratory, Orlando, FL
Richard T. Mayer, (470) 897-7300, rmayer@ix.netcom.com

Harvesting potato vines as cattle feed reduces pesticide and herbicide applications on potatoes. Potato vines are normally killed with herbicides about 2 weeks before the potatoes are harvested. This prevents the leftover vines from providing a home to insects and plant diseases that could harm the next year's crop. Now, ARS and University of Wisconsin scientists have found a way to harvest and store the vines and use them as cattle feed. They say potato vines can be turned into silage in combination with other crops such as chopped alfalfa, barley or entire corn plants to produce a high- protein, low-fiber cattle feed. The savings for U.S. potato growers could be as much as $42 million annually.
U.S. Dairy Forage Research Center, Madison, WI
Richard Muck, (608) 264-5245, remuck@facstaff.wisc.edu

A new sprayer and natural plant compounds could give growers better control over destructive silverleaf whiteflies and other soft-bodied pests. The whiteflies suck sap from leaves of more than 600 fruit, vegetable, fiber and ornamental plants. Plus, their saliva transmits plant diseases. The pests tend to cluster on undersides of leaves where insecticide spray doesn't reach very well. ARS scientists recently evaluated an ultrasonic fogger that delivers low dosages of insecticides in droplets that coat the top and bottom of the leaf. In tests, the fogger used far less insecticide but still killed a high percentage of whiteflies infesting collard plants. The scientists also screened 21 species of a wild tobacco plant, Nicotiana, for their commercial potential as sources of natural insecticidal compounds. The compounds, known as sugar esters, break down a soft-bodied insect's "skin" and cause the pest to dehydrate. The scientists found that the best commercial candidate overall was Nicotiana trigonophylla. Its esters are the least complex, are very concentrated and are comparatively easy to extract from the plant.
U.S. Vegetable Laboratory, Charleston, SC
Alvin M. Simmons/D. Michael Jackson, (803) 556- 0840, asimmons@awod.com/mjackson@awod.com

Goats might help stop the spread of tall whitetop, a weed that has cropped up in nearly every western state. The plant is also well established in New England. An ARS grazing experiment in Nevada with 13 young goats showed that the animals, fenced in a tall-whitetop- infested meadow, ate the white-flowered weed with no ill effects. That's important, because scientists aren't completely certain whether the plant is poisonous to animals. Ranchers and land managers today have no fast, effective way to fight the aggressive weed. Cattle and sheep graze tall whitetop, also known as perennial pepperweed, but won't tackle pure, dense stands of it. The goats, however, grazed thick stands along with regrowth from those stands and from mowed stands. They ate about 75 percent of the young, tender, more digestible regrowth, compared to about half the vegetation in older stands. Scientists are following up with another Nevada test, using about two dozen goats. Their ARS colleagues in Utah plan to use sheep in new tests of toxicity.
Ecology of Temperate Desert Rangelands Research, Reno, NV
James A. Young, (702) 784-6057, jayoung@scs.unr.edu
Poisonous Plant Research Laboratory, Logan, UT
Lynn F. James, (435) 752-2941, pbradfld@cc.usu.edu

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