ARS | Publication request: ALTERNATE HOSTS: IMPORTANT FACTORS IN THE WESTERN CORN ROOTWORM LIFE CYCLE

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 21, 2003
Publication Date: N/A

Technical Abstract: If registered, the introduction of transgenic corn will offer a viable alternative to insecticides for managing the western corn rootworm, one of the most economically important pests of corn. Maintaining susceptibility to transgenic crops (resistance management) is in the interest of growers and industry, but little is known about many aspects of corn rootworm biology. We have conducted a series of experiments to evaluate the importance that alternate hosts play in the life cycle of the western corn rootworm. Previously, we evaluated 28 species of major grassy weeds for their host status with western corn rootworm larvae in the greenhouse. Twenty-one of the species evaluated supported western corn rootworm larval growth at least to the third instar, and most of these grasses can be found in or near corn fields. In field experiments in 2001 and 2002, we evaluated grassy weed species by themselves, with isoline nontransgenic corn and with transgenic corn. We demonstrated that adults were produced from five of nine grassy weed species evaluated, and more adults were produced from a combination of grass and transgenic corn than either the transgenic corn or the grass alone. Grasses in, near, and perhaps even distant from corn may play more of a role in the rootworm life cycle than most rootworm entomologists would have guessed. This information will be important to seed companies, the Environmental Protection Agency, and modelers in their attempts to develop resistance management plans for transgenic corn by providing more realistic assumptions in current mathematical models.