Inheritance and fitness costs of field-derived resistance to Cry3Bb1 corn by western corn rootworm.

Monday, December 7, 2015 - 4:10pm
Event Type: 

Seminar will be given by Aubrey Paulino, Iowa State University, Department of Entomology as a part of her M.Sc. defense.

Event will be held in E164 Lagomarcino Hall.

Abstract. The western corn rootworm (Diabrotica virgifera virgifera LeConte) is an economically important pest of corn.  One strategy used to manage western corn rootworm is the planting of transgenic corn that produces one or more Cry toxins derived from Bacillus thuringiensis (Bt). Refuges of non-Bt corn function to delay the development of resistance and the greatest delay is expected when the inheritance of resistance is recessive and there are associated fitness costs.  We characterized the inheritance of resistance of two strains (Elma and Monona) of western corn rootworm with field-derived resistance to the Bt toxin Cry3Bb1 and attempted to identify any fitness costs.  For both strains, the inheritance of resistance was nonrecessive. In a greenhouse experiment with the Monona resistant strain, no fitness costs of resistance were detected.  A possible fitness cost of delayed development time of less than one day was identified for the Elma resistant strain in a laboratory experiment. These results suggest that additional strategies beyond the refuge strategy are needed to delay western corn rootworm resistance to Bt.

The ENT seminar series is coordinated by Greg Courtney and Rick Hellmich. Please contact either of us with questions related to speakers' visits.