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Implementation of the Melcast Melon Disease Forecaster to Reduce Fungicide Use in South Carolina

Project Coordinator

Anthony P. Keinath
Clemson University
Coastal Research and Education Center
2865 Savannah Highway
Charleston, SC 29414-5332
843-766-3761
843-571-4654 (fax)

Project Duration: June 2, 1999 - December 31, 2000

Matching Funds
  Request Non-Federal Federal
First Year Funding 7,629  
Total Funding Request 40,000    

Abstract

Successful production of watermelon and cantaloupe in the southern United States requires regular applications of fungicides to prevent and control the diseases gummy stem blight, anthracnose, and Alternaria leaf blight. In place of calendar-based fungicide applications, a melon disease forecaster, Melcast, has been used in Indiana. Melcast uses hours of leaf wetness and temperature during those periods to calculate environmental favorability indices (EFI) for each 24-hr period. EFI accumulate to predetermined thresholds, 20 and 35 EFI for cantaloupe and watermelon, respectively, at which time a fungicide is applied.

The goal of this project is to implement Melcast fungicide scheduling in South Carolina. Weather data will be purchased from SkyBit, Inc., for one to three sites in each of the seven major melon-producing counties in South Carolina for a total of 18 sites. Daily weather data sent electronically will be used to run the interpreter program of Melcast, which calculates the daily EFI values. Growers will be instructed to apply the first spray when vines begin to elongate. Thereafter, growers will obtain recorded EFI values from a toll-free number, electronic mail, or local radio broadcasts. Growers will tabulate and sum EFI and apply fungicides when the threshold values are reached for the sites closest to their fields.

Azoxystrobin (Quadris) was registered on cucurbits in March, 1999. This fungicide will work very well with Melcast to reduce the number and frequency of fungicide applications on watermelon and cantaloupe. Because azoxystrobin has systemic activity, it can eradicate infections which have not progressed to the colonization stage in the disease cycle. Therefore, the frequency of application can be reduced compared with protectant fungicides. Azoxystrobin has activity against a wide variety of plant pathogenic fungi, including those that cause gummy stem blight, anthracnose, and Alternaria leaf blight. As such, it can replace benomyl, thiophanate-methyl, mancozeb, and maneb and eliminate dietary and occupational risks associated with exposure to these pesticides. In addition, using chlorothalonil as the mandatory rotation partner with azoxystrobin will reduce dietary exposure to chlorothalonil by one-third or one-half, depending on whether chlorothalonil is used every second or every third application.

The key environmental benefit of this project is a reduction in the amount of fungicide applied to watermelon and cantaloupe crops in South Carolina. A reduction in the number of fungicide applications will reduce environmental risks, particularly to aquatic life, since mancozeb, maneb, chlorothalonil, and benomyl are all toxic to fish and other aquatic life. There also would be significant human health benefits by reducing exposure to fungicides that are probable human carcinogens. Another benefit to implementation of Melcast is a reduction in the risk of fungicide resistance developing in target pathogen populations. With the registration and potential wide-spread use of azoxystrobin in 1999 and other strobilurins in the near future, this is the appropriate time to implement a scientifically-based method to reduce the frequency of fungicide applications. In previous research, the number of fungicide applications has been reduced by up to three per season. This project would benefit every watermelon and cantaloupe grower in South Carolina.

Project Title: Implementation of the Melcast Melon Disease Forecaster to Reduce Fungicide Use in South Carolina

Successful production of watermelon and cantaloupe in the southern United States requires regular applications of fungicides to prevent and control the diseases gummy stem blight, anthracnose, and Alternaria leaf blight. In place of calendar-based fungicide applications, a melon disease forecaster, Melcast, can be used to schedule fungicide applications only when environmental conditions favor development of diseases. In previous research, the number of fungicide applications has been reduced by up to three per season.

Objectives

  1. Reduce the amount of fungicide applied to watermelon and cantaloupe by implementing Melcast scheduling in the major melon-growing areas of South Carolina.
  2. Increase the number of melon growers using Integrated Pest Management by promoting Melcast forecasting in place of calendar-based fungicide applications.

Justification for Objective

The key environmental benefit of this project is a reduction in the amount of fungicide applied to watermelon and cantaloupe crops in South Carolina. This benefit will result from completion of both objectives of this project. A reduction in the number of fungicide applications will reduce environmental risks, particularly to aquatic life, since mancozeb, maneb, chlorothalonil, and benomyl are all toxic to fish and other aquatic life, with a 96-hr LC50 of < 1 ppm (Kovach et al., 1992). There also would be significant human health benefits, since according to a National Research Council study (Anon.,1987), fungicides are the most oncogenic pesticides. Mancozeb, maneb, and chlorothalonil are classified as probable human (B2) carcinogens and the benzimidazoles are possible carcinogens.

Another benefit to implementation of Melcast to reduce the frequency of fungicide applications is a reduction in the risk of fungicide resistance developing in target pathogen populations. DeWaard et al. (1993) stated that the most basic anti-resistance strategy is to minimize exposure of pathogen populations to fungicides. This is particularly important with systemic fungicides, such as the benzimidazoles and the strobilurins. Benomyl, a systemic fungicide, is no longer recommended by the manufacturer for control of gummy stem blight on cucurbit crops, because the gummy stem blight fungus is resistant to benomyl and thiophanate-methyl in South Carolina (Keinath & Zitter, 1998), Maryland (Everts, 1999), Texas (Miller et al. 1998), and Florida (T. Kucharek, pers. comm.). Because of resistance to benomyl, growers likely have increased their use of protectant fungicides, which have only one week of residual activity compared with two weeks for systemic fungicides (Keinath, 1995). With the registration and potential wide-spread use of azoxystrobin in 1999 and other strobilurins, such as kresoxim-methyl, in the near future, this is the appropriate time to implement a scientifically-based method to reduce the frequency of fungicide applications. Because South Carolina is situated in the middle of the southeastern region, the results obtained in this project can be readily extended to watermelon- and cantaloupe-growing states to the north and the south.

Watermelon is the vegetable crop grown on the largest acreage within the southern United States. Six states in the southern region account for 51.1% of the U.S. watermelon acreage (Table 1). Watermelon consumption in the United States has steadily increased the past three years (National Watermelon Promotion Board, 1998), and this trend is expected to continue as consumers respond to nutritional recommendations to increase consumption of fresh fruits and vegetables.

Table 1. Area planted (in acres) to watermelon in the southern United States, 1993-1997*

State
1993
1994
1995
1996
1997
Alabama
11,000
12,100
10,700
10,700
9,000
Florida
42,000
40,000
37,000
40,000
33,000
Georgia
37,000
37,000
38,000
42,000
34,000
Mississippi
8,000
8,500
7,600
7,800
7,300
North Carolina
9,000
9,500
11,400
10,400
9,800
South Carolina
10,500
12,500
13,500
11,000
9,600

*Source: Economic Research Service, USDA, NASS.

Cantaloupe (muskmelon) acreage is only one-quarter to one-third of the watermelon acreage in the southern U.S. (Table 2). However, the price per unit weight is approximately three times greater: $15/cwt for cantaloupe compared with $5/cwt for watermelon. Because of the greater value per acre, growers may be more likely to use fungicides on cantaloupe than watermelon, although this has not been documented. In the eastern U.S., 64%, 72%, and 61% of the watermelon and cantaloupe acreage is treated with the EBDC fungicides, chlorothalonil, and benomyl, respectively (Johnston, 1991). Because of the relatively high percentage of treated acres, it is likely that 95% of the melon acreage is treated with at least one fungicide.

Table 2. Acres of cantaloupes harvested in selected southern states, 1995-1997

State 1995 1996 1997
Georgia* 5,500 6,500 9,000
South Carolina 700* 1670** 2300*

*Source: Economic Research Service, USDA, NASS.
**Estimated by county Extension agents.

The two main foliar diseases on watermelon in the southern U.S. are gummy stem blight and anthracnose, whereas the two main foliar diseases on cantaloupe are gummy stem blight and Alternaria leaf blight. In South Carolina, for example, gummy stem blight was the disease most frequently identified (21 of 45 fields) in annual surveys of commercial watermelon fields during 1991 to 1995 (A. P. Keinath, unpubl.). Similarly, gummy stem blight (16 of 41 fields) and Alternaria leaf blight (6 fields) were the most common cantaloupe diseases in 1991 to 1997. The causal agent of gummy stem blight (foliar phase) and black rot (fruit phase) is the fungus Didymella bryoniae, which attacks only members of the Cucurbitaceae family. Likewise, Alternaria cucumerina infects only cucurbit foliage. The fungal pathogen Colletotrichum orbiculare causes anthracnose of cucurbits and several other crop families. D. bryoniae and C. orbiculare attack all above-ground parts of plants, although on watermelon, anthracnose fruit rot is observed more commonly than black rot, but black rot is more common than anthracnose on cantaloupe (Miller et al. 1998). Between cropping seasons, all three fungi persist in crop debris in soil and on infected volunteer cucurbit plants and cucurbit weeds. During the growing season, the severity of these diseases increases over time in the sigmoidal pattern that is typical of many foliar diseases. Warm, moist conditions favor anthracnose and Alternaria leaf blight, while wet conditions with moderate to warm temperatures are conducive for gummy stem blight.

In the southeastern U.S., e.g., North Carolina, South Carolina, Georgia, and Florida, gummy stem blight appears to be more destructive than anthracnose, but outbreaks of anthracnose continue to occur on watermelon. Furthermore, unusually heavy rains in June 1991 led to a severe gummy stem blight epidemic. Over 15% of the 12,900 acres of watermelon in South Carolina were abandoned before harvest, a loss of $1.2 million in on-farm income (SC Agricultural Statistics Service). Similar losses have been reported from research plots in several states (Table 3). On Western-type cantaloupe, up to 85% of the fruit have been lost to black rot (Miller et al. 1998), whereas losses of 40% due to Alternaria leaf blight have been observed in repeated experiments (Latin, 1992).

Table 3. Losses in marketable yield (by weight) of watermelon due to gummy stem blight

State and reference Yield loss in nonsprayed plots* Income lost per acre (above preharvest production costs)
South Carolina (Keinath, 1995) 39% $ 264
Louisiana (Johnson et al. 1995) 39% $1,041
Indiana (Latin, 1997) 36% $ 218

* Compared with sprayed plots with the maximum yield in the study.

Azoxystrobin, a new fungicide active ingredient, was granted national registration on cucurbits and other crops as Quadris in March 1999. Growers in South Carolina had already used azoxystrobin on watermelon under a 1998 state crisis exemption. Because of its notably low risks for harmful dietary and occupational exposure and ground and surface water contamination, this fungicide is poised to become the new standard for control of foliar fungal diseases on watermelon and other vegetable crops. Azoxystrobin has systemic activity and as such, can eradicate infections which have not progressed to the colonization stage in the disease cycle. Because of this systemic activity, the frequency of application can be reduced compared with the protectant fungicides mancozeb, maneb, and chlorothalonil. Therefore, the introduction of azoxystrobin into the fungicide arsenal provides a very useful and timely avenue to implement a method, such as Melcast, to reduce the frequency of fungicide applications on watermelon and cantaloupe. Azoxystrobin also has low toxicity to beneficial insects, a key property for pesticides used on cucurbits, which must be pollinated by bees.

Azoxystrobin has activity against a wide variety of plant pathogenic fungi, including those that cause gummy stem blight, anthracnose, Alternaria leaf blight, powdery mildew, and downy mildew on watermelon and cantaloupe. As such, it can replace benomyl, thiophanate-methyl, mancozeb, and maneb and eliminate dietary and occupational risks associated with exposure to these pesticides. In addition, using chlorothalonil as the mandatory partner with azoxystrobin will reduce dietary exposure to chlorothalonil by one-third or one-half, depending on whether chlorothalonil is used every second or every third application.

Many watermelon growers, especially in South Carolina, prefer to use several different fungicides rather than rely on only one material. According to a 1999 survey of 52 watermelon growers from across the state, the most common use pattern is alternating biweekly applications of mancozeb or maneb with chlorothalonil (Table 4). In addition, over half (69%) of the growers make one or two applications of a benzimidazole fungicide (benomyl or thiophanate-methyl) per month. Many growers who grow both antaloupe and watermelon use the same fungicide schedule for both crops. Therefore, alternating azoxystrobin with chlorothalonil fits their current approach to disease control and satisfies the use restrictions for azoxystrobin. Watermelon growers in South Carolina and other states prefer to use fungicides which are safe for their workers to handle and apply, a significant reason for their interest in azoxystrobin (B. O’Neal, Coosaw Farms, Fairfax, SC, pers. comm., 01/27/98).

Table 4. Fungicide use by South Carolina watermelon growers in 1998*

Fungicide Percent of growers reporting use Percent of growers using the fungicide
Weekly Biweekly Monthly Never
Benomyl 10 38 31 21 79
Thiophanate-methyl 4 12 35 50 50
Chlorothalonil 12 69 6 13 87
Maneb 10 40 17 33 67
Mancozeb 25 62 8 6 94

*Based on surveys of 52 growers (Keinath, 1999, unpublished).
*Source: Economic Research Service, USDA, NASS.
**Estimated by county Extension agents.

Literature Review

Watermelon growers in the southern United States rely heavily on fungicides to manage foliar diseases. The benefits of such fungicide applications have been documented recently in two collaborative projects, one in South Carolina and one in Oklahoma, funded by the National Pesticide Impact Assessment Program. Historically, applications of various fungicides to control gummy stem blight and anthracnose have increased watermelon yields by 9 to 19 Mg/ha and provided $10 to $14 return per dollar spent on fungicides (Keinath & Duthie, 1999). Therefore, it is reasonable to assume that fungicide applications will continue to benefit watermelon production in the future.

Integrated Pest Management programs for diseases cannot rely on scouting crops for pathogens because pathogens cannot be detected visually in the field prior to infection, colonization of host tissue, and reproduction. By this stage in the disease cycle, it is too late to apply a protectant fungicide (Schenck, 1968). Because the number and kind of systemic fungicides is limited, post-infection fungicide applications generally have not provided adequate disease control. In addition, reducing fungicide applications on watermelon was ineffective with a strict calendar-based schedule that did not cover the entire period from vine elongation to harvest (Keinath, 1995).

Using disease forecasting provides the benefits of i) scheduling fungicides when environmental conditions are conducive for disease development and ii) reducing fungicide applications without reducing disease control efficacy, yield, or economic returns. In the U.S., the TOM-CAST tomato disease forecaster consistently has reduced the amount of fungicide applied to tomato crops compared with weekly sprays, in some cases by as much as 50% (Gleason et al., 1995). In previous research with TOM-CAST in South Carolina, the number of fungicide applications was reduced from 10 with a weekly schedule to seven with TOM-CAST (Keinath et al., 1996). Yields of all marketable and extra-large tomato fruit for the fresh market were equivalent with the two schedules. Net returns also were similar, averaging $3,000/ha more than in the nonsprayed control. Likewise, the AUPNUT peanut disease forecaster reduced the number of fungicide sprays applied by one to five per season compared with the standard 14-day schedule (Linvill and Drye ,1995).

“Melcast” is a weather-based spray advisory program for watermelon and cantaloupe developed by Dr. Richard Latin, Purdue University (Latin and Evans, 1996). The program uses hours of leaf wetness and temperature during those periods to calculate environmental favorability indices (EFI) for each 24-hr period. EFI accumulate to a predetermined threshold, at which time a fungicide is applied. In Indiana, Melcast has been used successfully to manage anthracnose and gummy stem blight on watermelon and Alternaria leaf blight on muskmelon. I have tested Melcast with chlorothalonil and mancozeb for control of gummy stem blight on watermelon in South Carolina the past four growing seasons. An initial “cover spray” applied no later than vine elongation is necessary for successful use of Melcast forecasting. When such a spray was omitted, disease control with Melcast was no better than a 14-day spray interval (Keinath, unpublished). However, when a cover spray was added, Melcast performed as well as a 7-day interval and eliminated one and three fungicide applications in a fall (Keinath et al., 1998) and a spring crop, respectively. Unpublished results obtained by Dr. Latin indicate that Melcast also can be used successfully with azoxystrobin (pers. comm., 06/26/98).

On cantaloupe, the time that Alternaria leaf blight affected = 1% of the foliage was linearly related to the percent yield loss (Latin, 1992). Soluble solids (sugar) content of fruit also decreased as the level of Alternaria leaf blight increased, and was positively correlated with yield loss (Latin et al., 1994). Such correlations have not held true for gummy stem blight on watermelon (Keinath, unpublished). Because watermelon can compensate for loss of healthy foliage, a higher threshold, 35 EFI, can be used for this crop than for cantaloupe (Roberts et al. 1998, Latin, 1997). A lower threshold, 20 EFI, has been used to schedule fungicide applications on cantaloupe because it is more sensitive to loss of healthy foliage than watermelon (Latin and Evans, 1996).

Two projects being conducted in the 1999 growing season will provide critical background information for implementing Melcast in South Carolina in 2000. Two on-farm trials of Melcast are being conducted, one with Mr. Johnny Crider, grower and Mr. Gilbert Miller, Extension agent, in Bamberg County, SC, and the other with Mr. Randy Cockrell, grower, in Jasper County, SC. These trials were initiated at the request of the growers and agent. Both trials include side-by-side watermelon fields, one of which will be sprayed according to Melcast scheduling, while the other is sprayed according to the grower’s standard schedule. Generally, growers use a 7- or 10-day schedule, occasionally modified based on field scouting and prevailing and expected weather conditions. In the Melcast fields, the first fungicide applications (the “cover sprays”) were made when the vines were approximately 40 cm long (2 to 3 weeks after transplanting). All subsequent applications will be made when EFI reach the threshold of 35.

A second project will be conducted at the Coastal REC, Charleston, SC, to compare Melcast scheduling with three different thresholds (25, 30, and 35 EFI) to 7- and 14-day calendar schedules. Three different fungicides, mancozeb, chlorothalonil, and azoxystrobin, will be used. This experiment is being repeated in Indiana and Florida as part of a cooperative project funded by the National Watermelon Promotion Board (Latin, Hopkins, and Keinath). The results of this project will be used to validate the 35 EFI threshold for watermelon.

Approach and Methods

Many South Carolina watermelon growers are familiar with Melcast already. The Melcast system will be explained to growers at three annual meetings early in 2000: the annual meeting of the SC Watermelon Association, the lower state watermelon meeting, which covers Allendale, Bamberg, Barnwell, Charleston, Colleton, and Hampton counties, and the Chesterfield County meeting in northern South Carolina. In addition, a presentation will be made to the Colleton-Bamberg Young Farmers Association. Melcast record booklets, as designed for Indiana growers, will be distributed at these meetings. An initial estimate will be made of the number of growers likely to use Melcast, and the location of their farms will be noted to aid in site selection (next paragraph).

Weather data needed as inputs for the Melcast disease forecaster are hours of leaf wetness and temperature during those periods. Simulated weather data will be purchased from SkyBit, Inc. (Boalsburg, PA), which provides site-specific simulated weather observations. This approach has been used successfully with the TOM-CAST tomato disease forecaster (Gleason et al. 1997) in place of weather data collected on-site. The advantages of SkyBit data include daily delivery of weather data by electronic mail to a central location (Coastal REC) and a savings in time and labor of not distributing and maintaining local weather-recording instruments. Weather data will be purchased for one to three sites in each of the seven major melon-producing counties in South Carolina (listed in the previous paragraph) for a total of 18 sites. Sites will be selected after consultation with the cooperating county Extension agents and will be located within the largest clusters of melon acreage in each county. Daily weather data sent electronically to the Coastal REC and will be used to run the interpreter program of Melcast, which calculates the daily EFI values. Mr. Gilbert Miller, county agent in Bamberg county, also will receive SkyBit weather data and calculate and tabulate Melcast EFI as a backup against computer failure at the Coastal REC.

Growers will be instructed to apply the first spray when vines begin to elongate (Keinath et al., 1998). Thereafter, growers will call a toll-free number at the Coastal REC to obtain recorded EFI values. Alternatively, EFI values will be sent daily to any growers with electronic mail addresses. In addition, EFI values will be broadcast on local farm radio programs in Barnwell, Bamberg, and Hampton counties. Growers will tabulate and sum EFI and apply fungicides when the threshold values are reached for the sites closest to their fields. This will increase ownership in the program and follows the current practice, under which recommendations are made by Extension personnel but growers schedule their own pesticide applications. Daily EFI values also will be sent electronically to the cooperating county Extension agent in each of the counties. The thresholds previously established will be used: 20 and 35 EFI for muskmelon and watermelon, respectively. Growers will decide which fungicides to apply. Participating growers will be asked to maintain a list of all fungicide applications made (date, active ingredient, and rate) to fields under Melcast scheduling and any other melon fields sprayed according to their conventional schedule.

Downy mildew of cantaloupe, a potentially destructive disease which occurs each year in South Carolina, is not covered by Melcast. Growers will be instructed to either i) apply a fungicide with systemic activity against downy mildew (metalaxyl-chlorothalonil, metalaxyl-mancozeb, or fosetyl-Al) in a Melcast-scheduled spray on or after May 15 or ii) apply a fungicide with systemic activity against downy mildew if this disease is detected and reset the EFI tally after the application. Because Melcast uses a lower threshold for cantaloupe than for watermelon, the additional applications of mancozeb, chlorothalonil, or azoxystrobin made prior to May 15 will aid in preventing downy mildew and may improve downy mildew control over the conventional spray programs currently used.

Impact Assessment

By using an 800-number based delivery system, I will be able to track the number, location, and frequency of calls to access the Melcast information. This is a very easy, reliable, and objective measurement of the success and impact of the program, in terms of the number of growers using Melcast. In addition, I will have the names of growers who receive EFI via electronic mail. The county agent cooperators will supply estimates of the acreage covered by the Melcast program through contacts with growers in their counties. The expected number of fungicide applications for each location and county will be known. Estimates of the reductions in fungicide applications compared with 7- and 10-day schedules will be calculated.

Selected growers will be asked to provide copies of their WPS pesticide application records so that the number and kind of fungicide applications made in 1998, 1999, and 2000 can be compared. In addition, all growers who have accessed the Melcast number at least once per week will be sent a follow-up questionnaire at the end of the season. The questionnaire will include questions about the number, rate, frequency, and kind of fungicide applications made in 1998, 1999, and 2000. The Environmental Impact Quotient (EIQ) will be calculated for watermelon and cantaloupe for each of the three years for all six counties and, if enough data are available, for each county individually to measure overall environmental impacts (Kovach et al. 1992). Azoxystrobin has a much lower EIQ, 15.9, than benomyl (69.5), chlorothalonil (46.0), mancozeb (62.3), maneb (64.1), and thiophanate-methyl (51.5). By reducing the total number of fungicide applications by 25% with Melcast and substituting azoxystrobin for half of the applications in the typical mancozeb-chlorothalonil rotation, the aggregate impacts on farm workers, consumers, and the environment could be reduced from 974.7 to 359.1, a reduction of 63%.

Appendix A. Literature Cited

Anonymous. 1987. Regulating Pesticides in Food: The Delany Paradox. National Academy Press, Washington, D.C. 272 p.

De Waard, M. A., Georgopoulos, S. G., Hollomon, D. W., Ishii, H., Leroux, P., Ragsdale, N. N., and Schwinn, F. J. 1993. Chemical control of plant diseases: problems and prospects. Annu. Rev. Phytopathol. 31:403-421.

Everts, K. L. 1999. First report of benomyl resistance in Didymella bryoniae in Delaware and Maryland. Plant Dis. 83:304.

Gleason, M. L., MacNab, A. A., Pitblado, R. E., Ricker, M. D., East, D. A., and Latin, R. X. 1995. Disease-warning systems for processing tomatoes in eastern North America: Are we there yet? Plant Dis. 79:113-121.

Johnson, C. E., Payne, J. T., and Buckley, J. B. 1995. Evaluation of fungicides for gummy stem blight control on watermelon. Fungic. Nematic. Tests 50:184.

Johnston, S. A., ed. 1991. Fungicide Benefits Assessment, Vegetables-East. USDA, NAPIAP.

Keinath, A. P. 1995. Fungicide timing for optimum management of gummy stem blight epidemics on watermelon. Plant Dis. 79:354-358.

Keinath, A. P., DuBose, V. B., May, W. H. III, and Latin, R. X. 1998. Comparison of seven fungicide intervals to control gummy stem blight in a fall watermelon crop. Fungic. Nematic. Tests 53:268.

Keinath, A. P., and Duthie, J. A. 1998. Yield and quality reductions in watermelon due to anthracnose, gummy stem blight, and black rot. Pages 77-90 in: Recent Research Developments in Plant Pathology, Vol. 2. Research Signpost, Trivandrum, India.

Keinath, A. P., and Zitter, T. A. 1998. Resistance to benomyl and thiophanate-methyl in Didymella bryoniae from South Carolina and New York. Plant Dis. 81:479-484.

Kovach, J., Petzoldt, C., Degni, J., and Tette, J. 1992. A method to measure the environmental impact of pesticides. NY Food Life Sci. Bul. 139.

Latin, R. X. 1992. Modeling the relationship between Alternaria leaf blight and yield loss in muskmelon. Plant Disease 76:1013-1017.

Latin, R. 1997. Evaluation of fungicides for control of gummy stem blight of watermelon. Fungic. Nematic. Tests 52:196.

Latin, R. X., and Evans, K. J. 1996. Development and delivery of a forecaster for Alternaria leaf blight of muskmelon. (Abstr.) Phytopathology 86:S106.

Latin, R., Rane, K. K., and Evans, K. J. 1994. Effect of Alternaria leaf blight on soluble solids content of muskmelon. Plant Disease 78:979-982.

Linvill, D. E., and Drye, C. E. 1995. Assessment of peanut leaf spot disease control guidelines using climatological data. Plant Dis. 79:876-879.

Miller, M. E., Isakeit, T., and Hernandez, R. A. 1998. Evaluation of fungicides for gummy stem blight control on muskmelon. Fungic. Nematic. Tests 53:159.

Roberts, W., Duthie, J. A., Edelson, J. V., Shrefler, J. W. 1998. Watermelon foliage and yield relationships. (Abstr.) HortScience 33:598.

Schenck, N. C. 1968. Fungicidal control of watermelon downy mildew and its relationship to first infection in the field. Plant Dis. Reptr. 52:979-981.

Appendix B. Timetable

Appendix C. Major Participants

Randy Cockrell, Cockrell Farms, Ehrhardt, SC. Farmer of row crops, watermelons, and hogs. Past president, SC Watermelon Association and current member of the National Watermelon Promotion Board. Cooperating watermelon farmer.

Anthony P. Keinath, Associate Professor of Plant Pathology, Clemson University, Charleston, SC (resume p. 15-16). Project Coordinator.

Richard X. Latin, Professor of Plant Pathology, Purdue University, W. Lafayette, IN (resume p. 17). Advisor on Melcast.

J. Marion Barnes, Colleton County, Clemson Cooperative Extension Service, Walterboro, SC (resume p. 18). Local coordinator for Colleton County.

Roger Francis, Charleston County, Clemson Cooperative Extension Service, Charleston, SC (resume p. 19-20). Local coordinator for Charleston County and Edisto Island.

Gilbert Miller, Bamberg County, Clemson Cooperative Extension Service, Bamberg, SC (resume p. 21-22). Local coordinator for Bamber County and back-up weather data archiving.

Joe Varn, Barnwell County, Clemson Cooperative Extension Service, Barnwell, SC (resume p. 23). Local coordinator for Barnwell County.

James Thomas, Allendale County Clemson Cooperative Extension Service, Allendale, SC. Local coordinator for Allendale County

Project Budget

Project Period: June 2, 1999 - December 31, 2000

Budget Category

Grant Funding

 Other Funding Total Funding
Personnel
6,677
   6,677
Fringe Benefits 1,736   1,736
Travel 3,426   3,426
Equipment      
Supplies 11,900   11,900
Contractual 5,100   5,100
Other: Indirect Costs @ 38.7% 11,161   11,161
Total 40,000   40,000

Supplies: Installation of four (4) auto attendant ports which will consist of one main number and three rotary numbers. The system will include a menu arranged by county and a service that growers can use to leave messages. Enterprise Telephone has been chosen as the facility to install the software and hardware required since they are the certified service center for our telephone system, Comdial DigiTech. Not only can they install the hardware and software for this telephone system, but they can provide the lines needed and obtain the 800 number required. They will also be able to provide service to maintain this entire system to insure that this service is available beyond the length of this proposal.

Other: Indirect Cost is calculated at 38.7% of total minus equipment.

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