Higher levels of virulence to multiple resistance genes were detected in Hessian fly (Mayetiola destructor) populations from Texas

Hessian fly is an important pest of wheat worldwide and is of particular importance in Texas and the southeastern United States. Texas is the highest wheat-producing state that is severely impacted by this insect. The most effective control in these areas is an integrated pest management program, including resistant varieties of wheat. Hessian fly populations are genetically diverse and can rapidly become virulent to specific resistance genes once they are widely deployed in a region. Knowing the current virulence status of regional fly populations is important for wheat breeders and producers. In this study, a virulence analysis was conducted on populations sampled in the northeastern and central Texas regions. This analysis showed that resistance genes H12, H13, H20, H22, H25, H26, H28, H29, H32, H33, H34, and Hdic are still highly effective in these regions. However, it is also evident that Texas fly populations have become more virulent to existing genes in the past 10 years, with very high levels of virulence to resistance genes H3, H5, vH6, H7/H8, H9, H10, H14, H15, H23, H24, H31, and H35/H36.