Department of Entomology

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Pesticide Formulation - Dust
(Virginia Tech Pesticide Programs, 02/01/2022)
Dust formulation placed on a dish.
Postemergence growth of the ovarian follicles of Aedes aegypti
Hagedorn, H. H.; Turner, Sarah; Hagedorn, E. A.; Pontecorvo, David; Greenbaum, Paula; Wheelock, Geofrey; Flanagan, T. R. (1977)
Growth of the ultimate follicle to the resting stage in Aedes aegypti is linear and reaches maximum development about 6Ohr after emergence. Decapitations and ligations at various times after emergence indicate that growth of the follicles is under the control of factors from the head and thorax. Release of head factor occurs within one day after emergence and is relatively sudden. The thoracic factor is released gradually over a 2 to 3 day period. Near normal growth of follicles in isolated abdomens after topical application of juvenile hormone (JH) indicates that the thoracic factor is JH from the corpora allata and demonstrates the feasibility of using this system as a JH assay. When ecdysone was injected simultaneously with JH the follicles failed to grow.
Cucumber pollen germination and tube elongation inhibited or reduced by pesticides and adjuvants
Gentile, A. G.; Vaughan, A. W.; Pfeiffer, Douglas G. (1978)
Commercial formulations of 5 insecticides: diazinon, dicofol, endosulfan, malathion, and Pyrenone* (6% pyrethrins and 60% piperomyl butoxide); 2 fungicides: captan and Manzate* (zinc and manganese ethylene bisdithiocarbamate); and 9 adjuvants: Fomex*, Multi-Film X-77*, NuTrex*, Dupont Spreader Sticker*, Bio-88*, Target-E*, Bio-Film*, Dupont Surfactant F*, and Regutaid* severely reduced germination of cucumber pollen on an artificial medium. A lesser degree of reduction in germination was caused by the insecticides carbaryl and methoxychlor, the' fungicide benomyl, and the adjuvants Regulaid*, Triton B-1956* and Chevron Spreader Sticker*. Carbaryl, methoxychlor and benomyl were used at spray concentrations of active ingredients recommended on the labels in 100 gal (378.5 liters) of water. The remainder of the pesticides was used at concentrations below label recommendations. Diazinon applied under controlled conditions to hand-pollinated pistillate flowers of cucumbers in greenhouse caused parthenocarpy and fruit abortion.
Coleoptera of poultry manure in caged-layer houses in North Carolina
Pfeiffer, Douglas G. (1980)
At least 120 species of Coleoptera were recovered from poultry manure in narrow, wide· span, and high-rise types of caged-layer poultry houses in the Mountains, Piedmont, and Coastal Plain regions of North Carolina. Carcinops pumilio (Erichson) and Alphitobius diaperinus (Panzer) were consistently the most abundant species in all 3 regions, followed by Gnathoncus nanus (Scriba) and the Aleocharinae (Staphylinidae). According to 5 indices of diversity, the Piedmont ranked 1st in overall diversity, species richness and equitability, followed by the Coastal Plain, and thirdly, by the Mountains. Narrow and high/rise house types were compared for adult and larval C. pumilio and A. diaperinus. The larval population peak for A. diaperinus occurred significantly earlier in the high-rise than in the narrow houses, however, the narrow houses had significantly higher beetle diversity. A qualitative examination of overwintering forms showed that most species overwintered primarily, but not exclusively, as adults.
Insect Identification Laboratory Annual Report 1981
Hilburn, Daniel J.; Allen, William A. (Virginia Tech, 1981)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1981.
Insect Identification Laboratory Annual Report 1982
Hilburn, Daniel J.; Allen, William A. (Virginia Tech, 1982)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1982.
Insect Identification Laboratory Annual Report 1983
Hilburn, Daniel J. (Virginia Tech, 1983)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1983.
Effect of tree fertilization on numbers and development of pear psylla (Homoptera: Psyllidae), and on fruit damage
Pfeiffer, Douglas G.; Burts, E. C. (1983)
Pear psylla, Psylla pyricola Foerster, egg and nymph density increased at a faster rate and reached higher levels on orchard pear, Pyrus communis L., trees receiving higher nitrogen application. This was probably due to psyllids ovipositing preferentially on foliage with higher nitrogen content. This preference was indicated in a choice chamber experiment using young and mature pear leaves. Differences in psylla densities on orchard trees due to nitrogen application rates were largely limited to the first half of the growing season. Nitrogen application rate had greater effect on psylla numbers than time of application (dormant vs. late summer). There was more russet damage to fruit from psylla on trees with a higher fertilization rate. Early-season nymphal populations were responsible for the differences in russet, highlighting the need for early-season control. Within certain ranges of foliar percent N, psylla developmental rate increased with plant nitrogen content. At very low levels of foliar N, however, psylla developmental rate also increased.
Insect Identification Laboratory Annual Report 1984
Hilburn, Daniel J.; Ravlin, F. William; Weidhaas, John A., Jr. (Virginia Tech, 1984)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1984.
Effect of tree fertilization on protein and free amino acid content and feeding rate of pear psylla (Homoptera: Psyllidae)
Pfeiffer, Douglas G.; Burts, E. C. (1984)
Tree nitrogen, assessed as foliar % N, phloem-cortex free amino acids, and leaf color all increased with tree fertilization, indicating an increase in nitrogen availability to pear psylla, Psylla pyricola Foerster. Free amino acid levels in psyllids increased with tree fertilization rate in orchard and growth room tests. Protein levels, however, were higher in psyllids from seedlings of medium nitrogen content than in those from low- or high-nitrogen seedlings. Psyllids from low-nitrogen seedlings weighed more than those from medium-nitrogen seedlings. Psyllid feeding rate, estimated by honeydew production, was compared on low- and high-nitrogen seedlings. Nymphs on very-low-nitrogen leaves produced more honeydew, suggesting a compensatory feeding response to low dietary nitrogen. Physiological, morphological, and ecological ramifications for pear psylla include effects on (1) adult protein content, (2) adult body size, and (3) nymphal developmental rate.
Insect Identification Laboratory Annual Report 1985
Hilburn, Daniel J.; Ravlin, F. William; Weidhaas, John A., Jr. (Virginia Tech, 1985)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1985.
Effects of field applications of paraquat on densities of Panonychus ulmi (Koch) and Neoseiulus fallacis (Garman)
Pfeiffer, Douglas G. (1986)
Neoseiulus fallacis (Garman) is the most important acarine predator of the European red mite, Panonychus ulmi (Koch), in sprayed apple orchards in the eastern United States [Poe, S. L., and W. R. Enns. 1969. Predaceous mites (Acarina: Phytoseiidae) associated with Missouri orchards. Trans. Missouri Acad. Sci. 3: 69-82; Berkett, L. P., and H. Y. Forsythe. 1980. Predaceous mites (Acari) associated with apple foliage in Maine. Can. Entomol. 112: 497-502]. Populations of this predator are often present only at very low densities in Virginia orchards, however. The herbicide paraquat has been shown to be toxic to N. fallacis using slide-dip bioassays [Rock, G. C., and D. R. Yeargan. 1973. Toxicity of apple orchard herbicides and growth-regulating chcmicnls to Neoseiulus fallacis and twospotted spider mite. J. Econ. Entomol. 66: 1342-1343; Hislop, R. G., and R. J. Prokopy. 1981 . Integrated management of phytophagous mites in Massachusetts (U.S.A.) apple orchards. 2. Influence of pesticides on the predator Amblyseius fallacis (Acarina: Phytoseiidae) under laboratory field conditions. Protect. Ecol. 3: 157-1721. Paraquat is commonly applied in Virginia apple orchards in early spring while N. fallacis is still in its overwintering site in the orchard ground cover. The purpose of this study was to determine if field applications of paraquat affect densities of P. ulmi and its predator, N. fallacis, in the tree canopy. Slide-dip bioassay data, while very useful for comparing toxicity from topical applications of pesticides, are highly artificial and do not reflect other factors in mortality (contact with dried residues, behavioral responses, habitat modification). Other methods should be employed to complement slide-dip data (Dennehey, T. J., J. Granett, and T. F. Leigh. 1983. Relevance of slide-dip and residual bioassay comparisons to detection of resistance in spider mites. J. Econ. Entomol. 76: 1225-1230).
Relative susceptibility to slide-dip application of cyhexatin in three populations of Panonychus ulmi (Koch) in Virginia apple orchards
Pfeiffer, Douglas G.; Pfeiffer, S. W. (1986)
Insect Identification Laboratory Annual Report 1986
Day, Eric R.; Ravlin, F. William; Weidhaas, John A., Jr.; Rutherford, Susan L. (Virginia Tech, 1986)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1986.
Insect Identification Laboratory Annual Report 1987
Day, Eric R.; Ravlin, F. William; Weidhaas, John A., Jr.; Rutherford, Susan L. (Virginia Tech, 1988)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1987.
Disruption of olfactory communication in oriental fruit moth and lesser appleworm in a Virginia peach orchard
Pfeiffer, Douglas G.; Killian, J. C. (1988)
Dispensers (20-cm polyethylene capillary tubing “ropes”) containing Oriental fruit moth pheromone were placed in a 4-ha block of peaches shortly before first male flight. This placement of ropes disrupted attraction to conventional pheromone traps for the duration of the season. Fruit damage was not significantly different from that in a control block (conventional pesticide application): twig damage was significantly lower relative to the control. Implications for pest management in mature and nonbearing blocks are discussed.
Insect Identification Laboratory Annual Report 1988
Day, Eric R.; Ravlin, F. William; Weidhaas, John A., Jr.; Rutherford, Susan L. (Virginia Tech, 1989)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1988.
Insect Identification Laboratory Annual Report 1989
Day, Eric R.; Ravlin, F. William; Weidhaas, John A., Jr.; Rutherford, Susan L. (Virginia Tech, 1990)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1989.
Insect Identification Laboratory Annual Report 1990
Day, Eric R.; Ravlin, F. William; Rutherford, Susan L. (Virginia Cooperative Extension, 1991)
This report summarizes the activity of the Insect Identification Laboratory at Virginia Tech for 1990.
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.

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