Effects of transgenic corn on the stalk borer, Papaipema nebris, and rearing techniques for the European corn borer parasitoid, Macrocentrus cingulum
The first part of this study assessed the efficacy of two different genetic events, event Bt 11 (Cry1Ab) and event CBH351 (Cry 9C), in Bt corn against two instar classes of the stalk borer, Papaipema nebris (Lepidoptera: Noctuidae), across three different plant stages (V1, V3, and V5). Stalk borer response and development over time were measured and the data from 1999 and 2000 show that the Bt corn does have some effect on the feeding and development of P. nebris. Injury to the corn plant was reduced, although not eliminated. Stalk borer larvae caused significantly (P=0.0001) more injury to the non-Bt plants than to the Bt plants over time. Growth and development of the larvae was slowed and mortality was higher for Bt corn than for non-Bt corn. Current data suggest that planting Bt corn may benefit growers by reducing, but not eliminating, stalk borer infestations. The second part of this study developed an up-to-date rearing guide for the European corn borer parasitoid, Macrocentrus cingulum (Hymenoptera: Braconidae), using literature and observations. Techniques were modified from a previous publication and advancements in the rearing of the European corn borer were included.