Progress 07/01/99 to 06/30/04
Outputs
Activity of two different strains of the entomogenous fungus, Nomuraea rileyi, was monitored in populations of Lepidoptera in soybeans. An early-season strain infected green cloverworm, beet armyworm, and corn earworm while a different strain infected velvetbean caterpillar when this pest appeared later in the season. Preliminary assessment of data from two years indicates that the glyphosate herbicide treatment and conventionally grown sudax treatment were most effective in reducing the yellow nutsedge infestations. The organically grown sudax was less effective than the conventionally grown sudax due to early season interference with annual weed and the apparent unavailability of nitrogen supplied using compost as an organic fertilizer which limited its growth. The predatory mirid, Engytatus modestus, was found feeding on aphids on tobacco plants in the field. We collected and reared this predator in the laboratory. Petri dish tests were carried out to assess its
predatory ability on white flies (Bemisia argentifolii) and tobacco aphids on tobacco and collard leaf parts. All the aphids were killed after 2 weeks in the dishes containing the tobacco leaves. However, few whiteflies on the collard leaves were attacked. Clearly the predatory ability depended upon the host plant because these predators take some of their nutrition from the host plant as well as from their prey. In collaboration with the Insect Biocontrol Laboratory in Beltsville, MD, the PxNPV of diamondback moth was increased in laboratory colonies of beet armyworm and a small field test was carried out in collard in Charleston, SC. The PxNPV plus the optical brightener, Blankaphor, was applied weekly from May 16 until June 13, 2003. Although the PxNPV treatment was not as good as the commercial insecticide Spintor, there was a significant reduction in numbers of diamondback moth larvae compared to the untreated control plots. Biological, chemical, and combinations of biological
and chemical seed treatments were tested on snap bean. Disease pressure was high, with a mean stand of only 46 percent, due primarily to damping-off caused by Pythium. The number of plants remaining 28 days after seeding was greater with Captan plus streptomycin than in the untreated control.
Impacts
Information from these studies will form the basis of a sustainable pest management system for vegetables and specialty crops. Emphasizing microbial pathogens and other biological control agents will protect natural enemies of insect pests and reduce environmental insult and costs to growers.
Publications
- Abudulai, M., B. M. Shepard, and P.L. Mitchell. 2001. Parasitism and predation on eggs of Leptoglossus phyllopus (Hemiptera: Coriedae) in cowpea: Impact of endosulfan sprays. Journal of Agricultural and Urban Entomology. 18: 105 - 115.
- Hassell, R. and B. Merle Shepard. 2002. Insect populations on Bacillus thuringiensis transgenic sweet corn. Journal of Entomological Science. 37: 285-292.
- Abudulai, M., B. M. Shepard and A. B. Salifu. 2003. Field evaluation of a neem (Azadrachta indica) based formulation Neemix against Nezara viridula (L.) Himiptera: Pentatomidae) in cowpea. International Journal of Pest Management. 49: 109-113.
- Abudulai, M., B. M. Shepard and P. L. Mitchell. 2003. Antifeedant and toxic effects of a Neem (Azadirachta indica) based formulation Neemix against Nezara viridula, (Himiptera: Pentatomidae). Journal of Entomological Science. 38: 398-408.
- Abudulai, M. and B. Merle Shepard. 2003. Effects of Neem (Azadirachta indica) on Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae), a parasitoid of Nezara viridula (L.) (Hemiptera: Pentatomidae). Journal of Entomological Science. 38: 386 - 397.
- Farrar, R. R., Jr., M. Shapiro and B. M. Shepard. 2004. Activity of the nucleopolyhedrovirus of the fall armyworm (Lepidoptera: Noctuidae) on foliage of transgenic sweet corn expressing the Cry1A(b)toxin. Environmental Entomology. 33: 982-989.
- Abudulai, M., B. M. Shepard and P.L. Mitchell. 2004. Effects of neem (Azadirachta indica A. Juss.) on predators of Nezara viridua (L.) (Hemiptera: Pentatomidae). Journal of Agricultural and Urban Entomology. Journal of Agricultural and Urban Entomology. 21: 9-13.
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Progress 01/01/03 to 12/31/03
Outputs
The major goal of this research is to identify alternative methods of pest control in vegetables, specialty crops and medicinal plants as complements to or as substitutes for conventional chemical pesticides. A high priority will be given to developing and evaluating alternative practices that are ecologically sound, economically feasible, and acceptable to growers. Corn earworm neonate larvae were fed a 1 percent and 5 percent concentration of a ground powder of the spider plant, Cleome gynandra and Tansy (Tanacetum parthenium). Larvae were held under laboratory conditions of about 68 degrees F and mortality was recorded. Diet incorporated plant material from both species of plants caused 100 percent mortality of the larvae at 5 percent. However, at 1 percent only the Tansy caused significant (23 percent) mortality. Cleome, at 1 percent concentration was not significantly different from the untreated control group. Tests on B.t. transgenic sweet corn (from Syngenta)
in 2003, expressing the Cry1a(b) protein, revealed that even though populations of corn earworm (CEW) Helicoverpa zea and fall armyworm (FAW) Spodoptera frugiperda were reduced in the transgenic sweet corn, damage to ears by these pests was still unacceptable. Therefore, applications of the botanical insecticide, neem (Neemix from Certis USA), the H. zea virus (Gemstar) at 2 and 3 times the recommended rate, and the commercial insecticide Spintor were made. Spintor plus the Bt transgenic sweet corn provided the best control and there was slight, but no significant, reductions in numbers of H. zea larvae per ear when Gemstar was applied. Spintor plus the Bt transgenic plants controlled FAW populations and produced nearly 90% marketable ears. The Bt transgenic plants alone yielded only about 12% marketable ears. None of the plants without the Bt gene survived attacks by FAW and no ears were produced. Overall, none of the treatments provided adequate control and rates and timing of
applications will be modified for field experiments in 2004. Studies of isolates of the nucleopolyhedrosis virus (SeMNPV) of beet armyworm (Spodoptera exigua) were concluded in 2003 and a manuscript has been submitted for publication. The local isolate field collected from South Carolina cotton fields was the most virulent of all isolates tested and this isolate will be evaluated in field tests. Studies were continued in 2003 on the fungal pathogen, Nomuraea rileyi, one of the most important regulating agents in larval populations of Lepidoptera. Studies were conducted to identify and characterize local strains of this fungus based on biological and molecular properties.
Impacts
Information from these studies will form the basis of a sustainable pest management system for vegetables and specialty crops. Emphasizing microbial pathogens and other biological control agents will protect natural enemies of insect pests and reduce environmental insult and costs to growers.
Publications
- Dufault, R. J., J. Rushing, R. Hassell, B. M. Shepard, G. McCutcheon and B. Ward. 2003. Influence of fertilizer on growth and marker compound of field-grown Echnachea species and feverfew. Scientia Horticulturae 98: 61-69.
- Abudulai, M. and B. M. Shepard. 2003. Cowpea damage simulation to determine critical reproductive stages. Journal of Agricultural and Urban Entomology. 20: 25-29.
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Progress 01/01/02 to 12/31/02
Outputs
This project emphasizes development of sustainable management of arthropod pests of vegetables and medicinal plants without the use of commercial chemical pesticides. Habitat manipulation is a part of this strategy. Studies were carried out in collard (Brassica oleracea) planted to plots with all weeds removed (bare soil) and in plots with white clover (Trifolium repens) and both beneficial and pest insects were monitored. The white clover plots also supported a community of weeds, the main ones being cornspurry and Bahiagrass. The presence of weeds and clover significantly reduced collard yields. It is likely that reduction was a result of allopathic effects from both weeds and clover because pest populations did not reach levels that would affect yields. Laboratory bioassays were carried out against the southern green stink bug (Nezara viridula) and the fall armyworm (Spodoptera frugiperda), important vegetable insect pests, using extracts from China berry (Melia
azedarach) and tansy (Tanacetum vulgare). Incorporation of 2% tansy oil into artificial diet caused 73% mortality of fall armyworms 48 hours post-treatment. No mortality was observed when 4 stage N. viridula were dipped in the same concentration. Extract (2%) from Melia caused 50% mortality in the fall armyworm after 72 hours but only 15% mortality in N. viridula. In plantings of feverfew (Chrysantheum parthenium) a new thrips pest (Thrips nigropilosus) was observed for the first time. Weekly suction samples revealed that as populations of the big-eyed bug (Geocoris spp.) and the minute pirate bug (Orius insidiosus) increased, there was a general decline of T. nigropilosus populations. Insect and spider communities were suction sampled in feverfew, St. Johns Wort, Valerian, Echinacea and Tansy. Feverfew had the overall highest numbers of beneficial insects, and the the overall highest biodiversity of arthropod species. Releases of the predatory mite, Phytoseiulus against the two
spotted spider mite under plastic row covers over strawberries revealed that after 2 releases of 1000 predators and 1 release of 2000 predators, populations of spider mites decreased by over 50% while the population density of the predator mite rose from 0.5 per leaflet to over 2.5 per leaflet. Clearly, biological control of spider mites was taking place.
Impacts
Information from these studies will help to make informed pest management decisions. Before recommending interplanting as a strategy to diversify the vegetable ecosystem, consideration must be given to the weed and cover crop species. Extracts from medicinal plants have the potential for becoming part of non-commercial insect management by offering a natural product alternative. Tansy and melia extracts have the potential of becoming an essential part of organic pest control. The use of predatory mites for control of spider mites on strawberries under row covers will probably be the mite management tactic of choice in this system.
Publications
- Abudulai, M. and B. M. Shepard. 2002. Efffects of Neem (Azaciracta indica) on Trissolcus basalis (Hymenoptera: Scelionidae), a parasitoid of Nezara viridula (Hemiptera: Pentatomidae). Journal of Entomological Science (accepted for publication).
- Abudulai, M. and B. M. Shepard. 2002. Field evaluation of a neem (Azadiracta indica)- based formulation of Neemix against Nezaara viridula (Hemiptera: Pentatomidae). International Journal of Pest Management (accepted for publication).
- Hassell, R. L., and B. M. Shepard. 2002. Insect populations on Bacillus thuringensis transgenic sweet corn. Journal of Entomological Science. 37: 285-292.
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Progress 01/01/01 to 12/31/01
Outputs
Because of the detrimental effects on sunlight on the stability of insect viruses in the field, a study was designed to determine the effectiveness of optical brighteners for protecting nucleopolyhedrisis viruses of Spodoptera exigua (SeMNPV). Blankophor HRS (1% wt:wt) was added to the polyhedral solutions. Four isolates of NPVs, i.e., SeMNPV-US2, SeMNPV-ID2, Spod-X and SliMNPV were tested. Serial concentrations of polyhedral solution (with or without brightener) then were exposed or not exposed to artificial sunlight. Two different exposure time periods were tested, i.e. 60 and 30 minutes. Two different light intensity were tested, i.e., 500 and 250 mirowatts/cm2. Bioassays were conducted against beet armyworm a serious pest of a number of vegetable crops. Addition of 1 percent Blankophor HRS to the polyhedral solution protected virus from degradation by sun light. Blankophor enhanced the infectivity of SeMNPV-US2 and Spod-X. LC50 values of SeMNPV-US2 and Spod-X plus
1 percent Blankophor were 165 and 135 times lower than the same viruses without brightener and unexposed to light. Planting dates affected populations of both corn earworm and fall armyworm in sweet corn in Charleston in 2001. Numbers of corn earworms per ear reached 2 in the early-planted crop that was harvested on August 28, 2001. However, in the later-planted crop, corn earworms dropped to below one per ear. Similarly, fall armyworm numbers in ears were about 0.25 per ear in the first crop (planted on June 26, 2001) which was harvested on August 28, 2001, but no fall armyworm larvae were detected when the crop was planted on July 17 and harvested on September 24, 2001. Time of planting may become an important tactic in escaping heavy damage by these pests. A scouting program was developed that uses estimated thresholds gathered from research conducted in other areas on other Brassica varieties. In addition to the scouting procedures, the program combined augmentative releases of
two parasitoid species, Trichogramma pretiosum and Cotesia plutellae along with the use of Bacillus thuringiensis, when called for by the scouting results. This approach reduced numbers of applications of pesticides (from 14 - 16 times per crop to 4 - 6), without loss of yield or crop quality. Field sampling also revealed that one of the parasitoid species, Cotesia plutellae, was spreading naturally to other areas of the county. Growers were satisfied with these results, although the overriding consensus was that the scouting procedure was time consuming and the thresholds needed to be determined by local collard research. A sequential sampling (field scouting)program was developed to manage the two principal caterpillar pests of collard, the DBM (Plutella xylostella) and the CL (Trichoplusia ni). This field scouting program significantly reduced field scouting time without loss of precision.
Impacts
The implications are that the efficacy of insect viruses in the field can be greatly enhanced and rates reduced by adding of optical brighteners to the virus formulation. This should reduce the amount of virus needed and thereby reduce expense. Knowledge of proper planting dates could escape damage by certain insect pests and an efficient field scouting method could reduce unnecessary chemical applications. These tactics should for the basis of an effective integrated pest management program for pests of vegetables and medicinal plants.
Publications
- Abudulai, M. and B. M. Shepard. 2001. Timing insecticide sprays for control of pod-sucking bugs (Pentatomidae, Coreidae, and Alydidae) in cowpea (Vigna unguiculata [L.] Walpers). Journal of Agricultural and Urban Entomology. 18: 51-60.
- Shepard, B. M., E. F. Shepard, G. R. Carner, M. D. Hammig, A. Rauf and S. G. Turnipseed. 2001. Integrated pest management reduces pesticides and production costs of vegetables and soybean in Indonesia: Field studies with local farmers. Journal of Agromedicine. 7: 31-66.
- Abudulai, M., B. M. Shepard, and P.L. Mitchell. 2001. Parasitism and predation on eggs of Leptoglossus phyllopus (L.) (Hemiptera: Coriedae) in cowpea: Impact of endosulfan sprays. Journal of Agricultural and Urban Entomology. 18: 105-115.
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Progress 01/01/00 to 12/31/00
Outputs
Using data collected from six grower fields over the early and late summer seasons and regression analysis, we determined that 7 cabbage looper larvae per 100 collard plants was an acceptable action threshold for making spray decisions. This would translate into 35 diamondback moth larvae per 100 plants using Cabbage Looper Equivalents. Time required to field sample collards for caterpillar pests was reduced by 90% using the sequential sampling plan. Numbers of southern green stink bug (SGSB) feeding punctures on cowpea, as determined by the acid fuscin test, were significantly reduced when pods were treated with neem, especially at a concentration of 5%. Treatment of late-instar SGSB with neem resulted in deformed adults that could not feed or reproduce. Predators or parasitoids of the egg masses of SGSB were not affected when host egg masses were treated with neem. The USA strain of a virus (SeNPV) of beet armyworm was more virulence than the Indonesian strain.
Among the NPVs that originated from other armyworms, Spodoptera ornithogalli (SoMNPV) was the most virulence against beet armyworms, followed by viruses from Spodoptera litura and Spodoptera littoralis. Numbers of diamondback moth, cabbage loopers and imported cabbageworms in collards were significantly higher in Karate-treated plots and lowest in those treated with the experimental B.t. formulation TTC - 1507 (from Thermotrilogy).
Impacts
Efficient field sampling techniques and newly identified biological control agents will be useful in integrated pest management systems in vegetables. Biological materials such as entomopathogenic viruses, nematodes and parasitoids as well as the botanical material neem are compatible and will conserve indigenous natural enemies of pests. Communities of parasitoid species on vegetable crops in Indonesia may play a role in biological control of insect pests in the U.S.A. The integration of all alternatives to chemical insecticides will result in more stable and more economical vegetable production systems.
Publications
- Shepard, B. M., Samsudin and A. R. Braun. 1998. Seasonal incidence of Liriomyza huidobrensis (Diptera: Agromyzidae) and its parasitoids on vegetables in Indonesia. International J. of Pest Mgt. 44: 43-47.
- Shepard, B. M. and N. A. Schellhorn. 1998. A Plutella/Crocidolomia management program for cabbage in Indonesia. Proceedings of the Third International Symposium on Management of Diamondback and Other Crucifer Pests. Kuala Lumpar, Malaysia, October 29 - November 1, 1997.
- Shepard, B. M., G. R. Carner, A. T. Barrion, P.A.C. Ooi and H. van den Berg. 1999. Insects and their natural enemies associated with vegetables and soybean in Southeast Asia. Quality Printing, Orangeburg, SC. 115 pp.
- Rauf, A., B. M. Shepard and M. Johnson. 2000. Leafminers in vegetables, ornamental plants and weeds in Indonesia: surveys of host crops, species composition and parasitoids. International Journal of Pest Management. 46: 257-266.
- Thang, M. H., B. Morallo-Rejesus and B. M. Shepard. 2000. Selectivity of acepahate and propaphos to the wolf spider, Pardosa pseudoannulata (Boes et Strand) and brown planthopper, Nilaparvata lugens (Stal). Part II. Metabolism. The Philippine Agricultural Scientist. 83: 272-281.
- Van den Berg, H., B. M. Shepard and H. Nasikin. 1998. Response of soybean to attack by stemfly, Melanagromyza sojae. In farmers' fields in Indonesia. Journal of Applied Ecology.
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Progress 01/01/99 to 12/31/99
Outputs
Surveys of plant feeding and beneficial arthropod species on medicinal plants revealed only one localized pest population of the silverleaf whitefly (Bemisia argentifolii) on Echinacea. At least 3 species (Encarsia pergandiella, Encarsia nigricephala and Eretmocerus sp.) of whitefly parasitoids were found on yellow sticky traps placed near the medicinal plants. Other than whiteflies, the most abundant plant-feeding insect in fever few (Tanacetum parthenium) was identified as Taylorilygus apicalis, a small green myrid but damage by this insect was not considered important. Predators were abundant and in many cases out numbered the plant-feeding species. Arthropod predators included ants, mostly Solenopsis invicta, coccinellids, big-eyed bugs, pirate bugs, hooded beetles, and damsel bugs. The most abundant spider was Pardosa melvinae (Lycosidae) which was commonly found on the soil surface. Fresh cowpea pods were treated with different concentrations of neem (Neemix
from Thermotrilogy). Numbers of southern green stink bugs (SGSB) feeding punctures were significantly reduced when pods were treated with neem. Also, treatment of late-instar SGSB with Neemix caused deformed adults that could not feed or reproduce. Because neem is "soft"on beneficial insects and spiders, it may be considered as a part of an ecologically-compatible program of insect control in several vegetable crops. Egg masses of the SGSB were treated with neem (Neemix) in "choice" and "no choice" laboratory tests to determine if the botanical material affected the major egg parasitoid, Trissolcus basalis. There were no significant differences in parasitism rates between the neem-treated and untreated eggs. Thus, the use of the plant-derived material, neem, may prevent feeding by the target insect pest without harming the beneficial species. A new initiative on strawberries was begun this year. Weekly monitoring revealed that major arthropods that affected the crop included the
yellow-striped armyworm, Spodoptera onithogalli, and the two-spotted spider mite, Tetranychus urticae. Both arthoropod pests occurred in damaging proportions in strawberries with row covers. Two species of predatory mites (Neoseiulus fallacis and N. californicus) were released on three different dates for control of the spider mites. In general, good biological control was achieved until later in the season when weekly scouting was not adequate to detect pest mite population build-up in time to suppress spider mite populations with introduced predators. Thus, scouting the crop at closer intervals will be required.
Impacts
These findings demonstrate that it is highly probably that chemical insecticides are not necessary for production of medicinal plants. Thus, economic and environmental costs associated with medicinal plant production should favorable. The use of neem (a botanical insecticide)for cowpea insect control should make cowpea production more sustainable. Control of mite and insect pests on strawberries can be accomplished using biological control.
Publications
- Dufault, R., R. Hassell, J. Rushing, M. Shepard, G. McCutcheon and A. Keinath. 2000. Revival of herbalism and its roots in medicine. Journal of Agromedicine (Accepted for publication).
- Dufault, R., R. Hassell, J. Rushing M. Shepard, G. McCutcheon and A. Keinath. 2000. Dilemma of regulating dietary supplements. Journal of Agromedicine. (Accepted for publication).
- Shepard, B. M. , G. R. Carner, A. T. Barrion, P.A.C.Ooi and H. van den Berg. 1999. Insects and their natural enemies associated with vegetables and soybean in Southeast Asia. Quality Printing, Orangeburg, SC. 108 pp.
- Luck, R. F., B. M. Shepard and P. E. Kenmore. 1999. Evaluation of biological control with experimental methods. pp. 225 - 242. (In) Handbook of Biological Control. Academic Press. N.Y. 1046 pp.
- Rauf A., B. M. Shepard and M. W. Johnson. 2000. Leafminers in vegetables, ornamental plants and weeds in Indonesia: Surveys of host crops, species composition and parasitoids. International Journal of Pest Management. (Accepted for publication).
- Mitchell, P. L, E. S. Paysen, A. E. Muckenfuss, M. Shaffer and B. M. Shepard. 1999. Natural mortality of leaffooted bug (Hemiptera: Heteroptera: Coreidae) eggs in cowpea. Journal of Agricultural and Urban Entomology. 16: 25 - 36.
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