In-Furrow Experimental Insecticide to Control Corn Rootworm.

Western corn root worm, Diabrotica virgifera virgifera, and northern corn rootworm, Diabrotica barberi, are important pests for field corn, Zea mays L. Corn rootworms are difficult to control because of their life cycle. Most growers control corn rootworm by using corn varieties that contain genetically modified traits, such as Cry35Ab1, Cry34Ab1, Cry3A, and Cry3Bb1. Corn rootworms have adapted and acquired resistance to some of the traits.

Two trials were conducted, one in Wisconsin, one in Minnesota to evaluate the influence of experimental in-furrow insecticides on the control of corn rootworms.  The Minnesota field was inoculated with western corn rootworm eggs using an in-furrow system. Each trial was a randomized complete block design with eight treatments. The experimental insecticides were compared to Capture LFR, bifenthrin, and an untreated check for yield and damage. Damage was assessed by observing the percentage of plants lodged and root chewing. Root chewing was assessed on eight plants collected from the center rows of each treatment. The roots were washed and rated using the Iowa State Interactive Node-Injury scale.