Managing WCR resistance to Bt on the fringe
By now you must have heard that for a few years corn growers in large portions of the Midwest have been battling populations of western corn rootworm that are resistant to YieldGard varieties of Bt corn (varieties carrying the Cry3Bb1 toxin). This problem is serious and growers in affected areas are trying any means necessary to protect their crops. (Here is a radio report that encapsulates the challenges growers face).
Populations of rootworms resistant to Bt technology are of course relevant for Pennsylvania, where we have plenty of farmers growing corn continuously. I trust you will agree with me that we want to do all we can to avoid having resistant beetle populations develop here at the eastern end of the Corn Belt. To this end, a group of extension entomologists in Indiana, Michigan, Ohio, Ontario, and Pennsylvania have developed a set of recommendations for managing populations of western corn rootworm on what we are calling “the fringe,” which contrasts with the focal area where resistance is already widespread. This issue is particularly relevant this time of year when western corn rootworm adults are emerging across Pennsylvania and any root damage will become evident as summer thunderstorms lead to lodged corn plants.
To read more about this issue and our consensus management recommendations, visit this new fact sheet.