Transgenic corn for corn rootworm control: Effect on corn rootworm biology and above and below ground nontarget organisms.

摘要

The western corn rootworm Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) is an important pest on corn in Kansas. Larvae feed on corn roots and adults on corn foliage and silks, Corn possessing a Bacillus thuringiensis toxin that is effective against this pest is being developed to control the larval stage of corn rootworms.; The objectives of this study were to: (1) determine the effect of Bt corn on survival of D. v. virgifera larvae, (2) determine the fecundity and longevity of D. v. virgifera adult beetles which survive exposure to Bt corn in the larval stage, (3) determine the fecundity and longevity of D. v. virgifera adult beetles which feed on Bt corn in the adult stage, (4) determine the effect of Bt corn for corn rootworm control on above-ground nontarget organisms (insidious flower bug and lady beetles), and (5) determine the effect of transgenic corn for corn rootworm control on ground and below ground nontarget organisms (ground beetles, spiders, earthworms, soil mites, and nematodes).; Bt and non-Bt corn hybrids were planted in fields at eight locations in Kansas in 2000 and three locations in 2001. Emergence cages were used to capture D. v. virgifera adults emerging from infested corn plots and the longevity and fecundity of captured beetles were assessed under laboratory conditions. In the laboratory, another group of D. v. virgifera beetles was fed on Bt and non-Bt corn silks and ears and their longevity and fecundity were determined. Different sampling methods were used to assess the potential effect of Bt corn on specific groups of nontarget arthropods (insects, spiders, and soil mites) and nematodes. These methods included visual inspection, soil handsorting, pitfall trapping, and Tullgren funnel extraction.; Bt corn significantly reduced the number of D. v. virgifera emerging from field infested corn plants. Bt corn had no significant effect on longevity and fecundity of D. v. virgifera that survived exposure to Bt corn roots in the larval stage in the field. Bt corn had no significant effect on the longevity and fecundity of D. v. virgifera which fed on Bt corn silks and ears in the adult stage. In general, Bt corn had no significant effect on the number of above and below ground nontarget arthropods. Bt corn (MON 863) was effective in controlling D. v. virgifera and did not have deleterious effects on the nontarget arthropods sampled.