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 Image Number D1907-3 |
Entomologists Aaron Gassmann (left), of Iowa State University, and Tom Sappington, with ARS, observe magnified western corn rootworm larvae to measure the size of their head capsules. Larvae exposed to Bt corn roots may grow more slowly than unexposed larvae, and head capsule width is an accurate indicator of larval growth stage.
Photo by Stephen Ausmus.
