VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.

Browsing by Author "Despins, Joseph L."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Evaluation of methods to protect poultry house insulation from infestations by lesser mealworm (Coleoptera: Tenebrionidae)
    Despins, Joseph L.; Turner, E. Craig Jr.; Pfeiffer, Douglas G. (1991)
    Insecticide sprays Bnd paint barriers Applied to the surface of extruded polystyrene, and different types of insulation, were evaluated for prevention of lesser melllwonn, Alphitobius diapcn"nlls (Panzer), infestations. In a lahoratOly study, tetrachlOlvinphos 50 ¥lP and pirimiphosmethyl 7E on extruded polystyrene produced> 90% mortality in larval and adult lesser mealwonn populations 71 wk after application. These insecticide spray treatments, however, were not effective under conditions found in the manure pit of a high rise cage layer house. Our field study showed that Styrofoam SS"" and Ethafoarn 220''', were resistant. to lesser mealwonn infestations. Super IQ'" paint., a latex paint impregnated with chlorpyrifos, was also effective in protecting extruded polystyrene from infestations under field conditions.
  • Thumbnail Image
    Investigations of the destructive behavior, and method for control of the lesser mealworm, Alphitobius diaperinus (Panzer), (Coleoptera: Tenebrionidae)
    Despins, Joseph L. (Virginia Polytechnic Institute and State University, 1986)
    The relationship between the types of construction of high rise caged layer houses and insulation damage produced by the lesser mealworm was examined. Polyurethane insulation which had heavy-weight paper glued to its surface and was installed with tape to seal off the seam between the insulation boards had no infestations. Structures with concrete block pit walls had lower insulation infestations than those houses with wooden walls forming the pits. Houses with a support structure set on top of the concrete block pit wall had lower infestations than houses built with the support structure set directly into the earth. The insulation installed nearest the pit was the most severely infested, and infestation intensity was inversely proportional to insulation height above the manure pit. Damage in extruded polystyrene insulation resulted in a substantial loss of volume of material in the corner areas of the insulation panels, and caused a significant reduction in insulating quality. Observations were made on the effect of manure moisture and poultry house construction materials on lesser mealworm dispersal behavior. Larvae and adults preferred manure habitats of 30 and 40% moisture, and dispersal from the manure significantly increased when manure moisture was increased to levels of 50 and 60%. Larvae climbed a significantly greater distance up a vertical wooden surface than up a vertical concrete block surface under field conditions. Results indicate that structures built with wood pit walls are predisposed to infestations, and that fluctuating manure moisture levels in these houses can indirectly contribute to accelerated infestation by driving the larvae from the manure pits into the insulation. Insecticide sprays, plastic films, paint barriers applied to the surface of extruded polystyrene, and different types of insulation were evaluated for lesser mealworm resistance. In a laboratory study, tetrachlorvinphos and pirimiphos-methyl sprayed on extruded polystyrene produced greater than 90% mortality in larval and adult populations up to 71 weeks postapplication. Larvae were unable to penetrate either chlorpyrifos-impregnated or non-insecticidal polyethylene films. Infestation intensity was inversely proportional to insulation cell size. Effective treatments identified under field conditions were permethrin and pirimiphos-methyl sprays, and two formulations of chlorpyrifos-impregnated latex paint. Insulation materials with a cell size of 1.5 mm were resistant to lesser mealworm field populations.
  • Thumbnail Image
    Phenology of the European corn borer, Ostrinia nubilalis (Hubner) (Lepidoptera: Pyralidae) in Virginia
    Despins, Joseph L. (Virginia Polytechnic Institute and State University, 1982)
    Flight activity of adult European corn borer field populations was monitored in Bedford County (1980 - 1981), Painter (1958 - 1980), Blacksburg (1971 - 1973, 1975) and Warsaw, Virginia (1971 - 1972, 1981). Peak occurrence of flight activity was accurately estimated by measuring the accumulation of degree days above 10ºC. The appearance of cumulative percentages of adult European corn borer flight at predicted degree day accumulations is reported. The seasonal abundance, within - field and within - plant distribution of first generation European corn borer egg masses were observed in field corn in Bedford County, Virginia. Peak egg mass abundance occurred ca. 200 degree days after the first borer moths were taken in the light traps. The spatial pattern of first generation corn borer egg masses closely approximated the Poisson distribution. The within - plant distribution of egg masses was skewed towards the lower leaves of the plant throughout the oviposition period, and nearly all egg masses were deposited on the leaf undersurfaces. Optimum sample sizes for two levels of sampling precision were developed from the sampling data. The seasonal development of the European corn borer in the spring was studied in relation to the flowering phenology of several groups of trees and wildflowers. The potential indicator plants signalled the onset of overwintering generation adult emergence, peak overwintering generation peak flight activity - first generation egg mass abundance, and the end of overwintering generation adult European corn borer flight.