[show abstract][hide abstract] ABSTRACT: Impacts of semiochemical-based insecticidal bait applications on beneficial arthropod groups common to field corn, Zea mays L., habitats were assessed in areawide-managed field sites in South Dakota and Iowa during 1997 and 1998. Slam, a commercial bait formulation comprised of 87% cucurbitacin and 13% carbaryl insecticide, was used for management of adult rootworm, Diabrotica spp., and controls consisted of cornfield habitats without bait applications. Effects on beneficial organisms were variable, and negative impacts were infrequent. Coccinellidae, Staphylinidae, and Anthocoridae were usually more abundant in bait-treated plots than in controls that received at-plant soil insecticides, especially by 4 wk postapplication. Carabid beetle activity also had increased in bait-treated corn by proportionally greater rates than in control plots at 4 wk postapplication in two of the four site by year combinations in this study. Impacts of semiochemical-based adulticide applications on Formicidae were not consistently negative or positive. The relative lack of consistent negative impacts on nontarget arthropods suggests that other biotic and abiotic factors leading to natural population fluxes may have more influence on these groups of beneficial organisms than applications of semiochemical-based bait containing carbaryl. Overall, it seems that areawide applications of these baits for managing rootworm populations in corn are not likely to impose deleterious effects on the nontarget faunal groups we surveyed, especially in comparison with the at-plant applications of soil insecticides used as experimental controls in this study.
Journal of Economic Entomology 01/2006; 98(6):1957-68. · 1.60 Impact Factor
[show abstract][hide abstract] ABSTRACT: Lady beetles (Coleoptera: Coccinellidae) are important polyphagous predators in maize, Zea mays L., fields. Transgenic Cry3Bb1 maize hybrids express a coleopteran-specific insecticidal protein derived from Bacillus thuringiensis (Berliner) subsp. kumamotoensis that is targeted at corn rootworm larvae. This study evaluated impacts of Cry3Bb1 protein-expressing maize, tefluthrin-treated maize, and untreated controls on lady beetle abundance at preanthesis, anthesis, and postanthesis maize-developmental periods near Brookings in eastern South Dakota during 2001 and 2002. The dominant lady beetle species captured on Pherocon AM sticky traps was Coleomegilla maculata De Geer. It comprised 73.5 and 69.9% of all adult Coccinellidae caught in 2001 and 2002, respectively. Numbers of C. maculata captured in Cry3Bb1 maize were not significantly different from those in untreated plots during preanthesis, and adults were more abundant in Cry3Bb1 maize than in tefluthrin-treated and untreated plots during anthesis and postanthesis. Whole-plant sampling confirmed C. maculata predominance with the species representing 89.2 and 91.4% of all adult lady beetles observed in 2001 and 2002, respectively. Whole-plant sampling also indicated a lack of negative effects from Cry3Bb1 maize on abundance of lady beetle eggs, larvae, pupae, or adults. Overall, these findings indicate that Cry3Bb1-expressing hybrids are not likely to impose harmful effects on C. maculata, a species common to maize production systems in the northern Great Plains. This research further suggests that Cry3Bb1 maize has the potential for conservation of these beneficial coccinellids in maize production systems.
Journal of Economic Entomology 01/2006; 98(6):1992-8. · 1.60 Impact Factor