Corn Rootworm Seed Treatments

Mike Rankin
Crops and Soils Agent
University of Wisconsin - Extension

        Seed treatments to control corn rootworm larval feeding are currently being promoted in many farm publication advertisements.  Although seed treatments offer a promising future for the control of corn rootworm, the current line-up of products falls short of the control you will achieve with more traditional soil applied insecticides.

        The two products currently being marketed are ProShield (contains tefluthrin, the same active ingredient as Force 3G) and Prescribe (contains imidacloprid as the active ingredient).  Root-rating data from Wisconsin and other Midwest universities concur that neither product offers consistent corn rootworm control.  At Iowa State University, ProShield  provided only a 22% consistency rating (based on the number of times a product limited the node-injury rating to no more than 25% of a single node) and Prescribe obtained only a 9% consistency rating.  Compare these results to that of Force 3G (in furrow) with a rating of 94% and Lorsban 15G (T-band) with a rating of 83%.  

        Another seed treatment, Gaucho, is also being marketed this winter.  This treatment contains the same active ingredient as Prescribe but at a lower rate.  However, in this case the product is marketed as a control for early season pests such as seed corn maggot, seed corn beetle, and wireworm.  Gaucho is an effective control measure for these pests.