@article{roe_young_iwasa_wyss_stumpf_sparks_watson_sheets_thompson_2010, title={Mechanism of resistance to spinosyn in the tobacco budworm, Heliothis virescens}, volume={96}, DOI={10.1016/j.pestbp.2009.08.009}, abstractNote={Topical laboratory selection of tobacco budworm larvae, Heliothis virescens, with technical spinosad for multiple generations resulted in larvae 1068-fold resistant to topical applications of the insecticide and 316.6-fold resistant to insecticide treated diet as compared to the parental strain. The penetration of 2′-O-methyl[14C]spinosyn A across the cuticle of the susceptible (parental) and selected (resistant) tobacco budworms increased with time 3–12 h after application. A trend of reduced penetration in the resistant strain was found but the differences were not statistically significant. 2′-O-methyl[14C]spinosyn A when injected into the hemocoel was not metabolized 96 h after treatment in both the susceptible and resistant strain, suggesting that a change in metabolism was not the mechanism of resistance. Electrophysiological studies indicated that dose-dependent spinosyn A-induced currents occurred in neurons from spinosyn resistant and susceptible (adult) tobacco budworms. At both 10 and 100 nM spinosyn A, however, the amplitude of these currents in the resistant insects was significantly smaller than the amplitude of currents observed from neurons from susceptible tobacco budworm adults. This suggests that neurons from resistant insects have decreased sensitivity to spinosyn A. However, the reduced inward currents in the resistant strain may or may not be related to the mode of action of the spinosyns. No statistically significant cross-resistance was noted for the spinosad resistant tobacco budworms for topical applications of permethrin (Pounce®), profenofos (Curacron®), emamectin benzoate (Denim®), or indoxacarb (Steward®). A statistically significant reduction in susceptibility to acetamiprid (Mospilan®) in artificial diet as determined from a resistance ratio of 0.482 was found.}, number={1}, journal={Pesticide Biochemistry and Physiology}, author={Roe, Richard and Young, H. P. and Iwasa, T. and Wyss, C. F. and Stumpf, C. F. and Sparks, T. C. and Watson, G. B. and Sheets, J. J. and Thompson, G. D.}, year={2010}, pages={8–13} }
 @article{witting-bissinger_stumpf_donohue_apperson_roe_2008, title={Novel arthropod repellent, BioUD, is an efficacious alternative to deet}, volume={45}, ISSN={["1938-2928"]}, DOI={10.1603/0022-2585(2008)45[891:NARBIA]2.0.CO;2}, abstractNote={For >50 yr, N,N-diethyl-3-methylbenzamide (deet) has been the standard for arthropod repellents and has been an important tool to protect people from disease agents carried by ticks, mosquitoes, and other arthropods. However, some people avoid using deet because of concerns about adverse health effects. In 2007, a new repellent, BioUD, with the active ingredient 7.75% 2-undecanone, originally derived from wild tomato (Lycopersicon hirsutum Dunal f. glabratum C. H. Müll) plants, was registered by the U.S. Environmental Protection Agency. In the current study, repellent efficacy of BioUD was compared using arm-in-cage studies with 7 and 15% deet against the mosquitoes Aedes aegypti (L.) and Aedes albopictus Skuse. No differences were found in mean repellency over 6 h after application between BioUD versus 7 and 15% deet for Ae albopictus. For Ae. aegypti, no differences were found over the same time period for 7% deet. Compared with 15% deet, BioUD mean repellency was lower over the 6-h test period. Human subject field trials were conducted in North Carolina, United States, and Ontario, Canada, comparing the repellency of BioUD to products containing 25 and 30% deet. BioUD provided the same repellency or was more efficacious than 25 and 30% deet, respectively, in these studies. Laboratory trials were conducted to determine the repellent activity of BioUD against the American dog tick, Dermacentor variabilis (Say), on human skin and cloth. BioUD repelled ticks at least 2.5 h after application to human skin. On cloth, no differences in mean repellency were found through 8 d after application between BioUD and 7% deet. In a two-choice test for BioUD versus 15% deet on filter paper, ticks spent significantly more time on the deet-treated surface than the BioUD-treated surface. Based on these studies in toto, BioUD is an efficacious alternative to deet in its repellent activity.}, number={5}, journal={JOURNAL OF MEDICAL ENTOMOLOGY}, author={Witting-Bissinger, B. E. and Stumpf, C. F. and Donohue, K. V. and Apperson, C. S. and Roe, R. M.}, year={2008}, month={Sep}, pages={891–898} }
 @article{stumpf_kennedy_2007, title={Effects of tomato spotted wilt virus isolates, host plants, and temperature on survival, size, and development time of Frankliniella occidentalis}, volume={123}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.2007.00541.x}, abstractNote={Tomato spotted wilt virus (TSWV) replicates in both its plant hosts and its thrips vectors. Replication of TSWV within thrips suggests the potential for pathological effects that could affect the fitness of its vectors directly, whereas infection of the plant may alter its suitability as a host for thrips development. This study was undertaken to examine the influence of TSWV isolate, host plant, and temperature on potential direct and host-mediated effects of virus infection of the thrips and the plant on Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), an important vector of TSWV. Neonate F. occidentalis were reared to adult eclosion on excised foliage of Datura stramonium (L.) (Solanaceae) or Emilia sonchifolia (L.) (Compositae) infected with either the CFL or RG2 isolate of TSWV, or not infected. Effects of the TSWV isolates and host plants on thrips were measured at 18.3, 23.9, and 29.4 °C. Results demonstrate significantly improved survival and a small but significant decrease in development time of F. occidentalis on TSWV-infected plants. These effects resulted from the combined influence of the direct effects of the virus on infected thrips and plant-mediated effects resulting from virus infection of the thrips’ host plant. Our results extend previous findings and help to explain inconsistencies among previously published reports by demonstrating that the manifestation and magnitude of effects of TSWV on F. occidentalis are dependent on host plant, virus isolate, and temperature.}, number={2}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Stumpf, Christof F. and Kennedy, George G.}, year={2007}, month={May}, pages={139–147} }
 @article{stumpf_comins_sparks_donohue_roe_2007, title={Insecticidal activity and mode of action of novel nicotinoids synthesized by new acylpyridinium salt chemistry and directed lithiation}, volume={87}, ISSN={["1095-9939"]}, DOI={10.1016/j.pestbp.2006.07.012}, abstractNote={Novel acylpyridinium salt chemistry and directed lithiation methodology was developed to add for the first time substitutions directly to the phenylpyridine heterocyclic ring of nicotine. A variety of 3-(1-methylpyrrolidin-2-yl)-4-(alkyl, aromatic, heterocyclic and silanyl) and -N-alkyl pyridines were synthesized (compounds 1–9). In vial tests with the green peach aphid, Myzus persicae, compounds 1–4 were 1.1, 1.8, 2.3 and 1.9×, respectively, more active than nicotine and 64, 40, 31 and 38×, respectively, less active than acetamiprid. Against the western flower thrips, Frankliniella occidentalis, 1–4 were 1.4, 2.1, 2.0 and 1.6×, respectively, more active than nicotine and 9, 6, 6 and 8×, respectively, less active than acetamiprid. For the cotton aphid, Aphis gossypii, the activity of 1–9 was similar to nicotine. Compounds 7 and 9 when incorporated into artificial diet produced low mortality for larvae of the beet armyworm, Spodoptera exigua, but were not active against the corn earworm, Helicoverpa zea. When 1–4 and 6–9 were injected into larvae of the beet armyworm, a variety of symptoms similar to acetamiprid were observed which included tremors, uncoordinated movement, diuresis, paralysis and death. In addition, imidacloprid-binding to membranes from the house fly head, Musca domestica, was inhibited by compounds 1–9, when using a concentration range of 1–100 μM. These studies demonstrate that our new chemistry enhances the insecticidal activity of nicotine with an apparent mode of action as an acetylcholine agonist.}, number={3}, journal={PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY}, author={Stumpf, Christof F. and Comins, Daniel L. and Sparks, Thomas C. and Donohue, Kevin V. and Roe, R. Michael}, year={2007}, month={Mar}, pages={211–219} }
 @article{stumpf_kennedy_2005, title={Effects of tomato spotted wilt virus (TSWV) isolates, host plants, and temperature on survival, size, and development time of Frankliniella fusca}, volume={114}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.2005.00251.x}, abstractNote={The effects of different isolates of the tomato spotted wilt tospovirus (TSWV), host plants, and temperatures on Frankliniella fusca (Hinds) (Thysanoptera: Thripidae), the most important vector of TSWV in North Carolina, were measured in the laboratory. Thrips were reared at either 18.3, 23.9, or 29.4 °C until adult eclosion on excised leaves of Datura stramonium L. or Emilia sonchifolia (L.). Plants were either infected with the TSWV isolates CFL or RG2, or left uninfected (control). The results revealed a positive relationship between larval survival and temperature, regardless of host plant or TSWV isolate. Both survival to adult and percentage transmission of TSWV by F. fusca were significantly affected by the interaction between host plant and TSWV isolate. The consequence of this interaction was that the cohort-based percentage transmission from infected E. sonchifolia plants for CFL was 1.3-fold greater than that of RG2, whereas the percentage transmission from infected D. stramonium plants for RG2 was twice that of CFL. Both host plant and TSWV isolates showed significant effects on thrips development time to adult and head capsule width of adult thrips, as well as on the incidence of thrips infection with TSWV. The infection status of these thrips was determined by ELISA for the NSs viral protein. Infected thrips reared on infected host foliage took longer to develop to adult and were smaller than non-infected thrips which had also been reared on infected host foliage, demonstrating a direct effect of the TSWV on thrips. However, non-infected thrips reared on non-infected leaves took longer to develop than non-infected thrips reared on infected leaves, suggesting an effect of the plant tissue on thrips. In addition, adult thrips reared on TSWV-infected D. stramonium at 29.4 °C developed smaller head capsules than thrips developing on infected foliage at lower temperatures and on non-infected leaves of D. stramonium or E. sonchifolia. Both TSWV isolates and host plants differentially affected females more than males. In conclusion, both the infection of thrips by TSWV and TSWV-mediated changes in host plant quality were found to have significant biological effects on F. fusca.}, number={3}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Stumpf, CF and Kennedy, GG}, year={2005}, month={Mar}, pages={215–225} }
 @article{stumpf_lambdin_2001, title={Distribution and phylogenetic relationships of native and introduced pit scales (Hemiptera: Coccoidea: Asterolecaniidae) in North and South America}, volume={33}, ISBN={0336-2403}, number={3}, journal={Bollettino di Zoologia Agraria e di Bachicoltura}, author={Stumpf, C. F. and Lambdin, P. L.}, year={2001}, pages={139} }