ARS | Publication request: ESTABLISHMENT AND MOVEMENT OF WESTERN CORN ROOTWORM LARVAE

Submitted to: Entomological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 14, 1999
Publication Date: N/A

Technical Abstract: The western corn rootworm is a major insect pest in continuous corn production, but no viable alternatives to insecticides are available for its control. Seed companies have announced commercialization goals for transgenic seed with resistance to corn rootworm larval feeding as early as 2001, yet little is known about certain aspects of corn rootworm biology that may be required as part of the registration process by the Environmental Protection Agency. The goal of the present study was to determine if and how much western corn rootworm larvae can move from plant to plant and row to row after larval establishment in a central Missouri environment. Plots were divided into two row spacings (91.4 cm and 45.4 cm) and two plant spacings (15.3 cm and 21.6 cm). For each plot, a central plant was infested with 1,500 viable western corn rootworm eggs. After egg hatch, soil cores were taken from the infested plant, the closest six plants within the row, and the two closest plants in each of the closest two rows. In 1999, four replications were sampled for each row spacing/plant spacing at four dates throughout the season (three sample dates were used in 1998). Significant larval movement was observed between plants within a row and between 46-cm (narrow) rows. Little movement (if any) occurred between 91-cm rows. Movement appeared to be correlated with plant damage. These results may impact determinations of the most appropriate type of 'refuge' for transgenic corn with resistance to corn rootworms.