Browsing by Author "Smith, John C."
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- Biological control agents of soybean insect pests in the Tidewater area of VirginiaEaton, Alan Tucker (Virginia Tech, 1975-01-05)The species of biological control agents which affect soybean pests in the Tidewater area were investigated, and their relative values were determined. Two pentatomids, Podisus Macu1iventris Say and Stiretrus anchorago F., were the only significant bio-contro1 agents which attacked the Mexican bean beetle, Epi1achna varivestis Mulsant. Thesepredators were not able to hold the pest population in check. A parasitic fly, Trichopoda pennipes F. was the only important biological control agent which attacked the green stinkbug, Acrosternum hilare (Say). Host and habitdt preferences of the fly suggested the presence of two strains in Virginia. Distribution of the fly was very uneven. Fungal disease was found to be an important control agent of many (larval) Lepidoptera. It was the most important control agent of Plachypena scabra (F.). P. scabra was also controlled by predation and parasitism. Nine parasites attacked the larvae and pupae. No effective biological controls were found for the corn earworm, Heliothis zea (Boddie). The only significant control agent, fungal disease, acted too slowly to prevent economic damage by this insect.
- Components of seasonal soybean infestation by Heliothis zea in eastern Virginia, with emphasis on multivariate analysis of field susceptibilityKnausenberger, Janice G. Burt (Virginia Tech, 1978-11-05)Heliothis zea (Boddie) (Lepidoptera: Noctuidae) density, development, and relationships with host crops were studied in eastern Virginia. Six instars occur. The larval population in corn is the reservoir for the generation in soybeans. An estimator, based on the reservoir population, permitted calculation of the larval density in soybeans. An index, based on blacklight trap and emergence data, permitted precise timing ot peak moth flight to soybeans. Regression analyses of biotic and abiotic factors revealed that soybean plant morphometrics best explained corn earworm densities. Discriminant analyses on empiricala priori soybean field susceptibility categories (described by plant morphometrics) classified five levels of anticipated maximum larval densities 80 - 98 percent correctly. Development of highest larval densities was synchronized with overall plant growth and specific pod development: third and fourth instars were present during rapid pod elongation, while fifth and sixth were present during rapid pod volume increase.
- Pest management guide for peanutsSmith, John C.; Phipps, Patrick M.; Rud, O. E. (Virginia Cooperative Extension Service, 1981-01)
- Pest management guide for soybeansMcPherson, Robert M.; Smith, John C.; Roberts, James E. Sr.; Phipps, Patrick M.; Rud, O. E.; Wilson, H. P.; Foy, Chester L. (Virginia Cooperative Extension Service, 1981-01)