Recommendations for managing spider mites in corn and soybean, including treatment thresholds, insecticides as well as discussions on the potential impact of beneficial insects, diseases, and insecticide applications.
Two species of spider mites, the Banks grass mite and the twospotted spider mite, commonly feed on Nebraska corn. Banks grass mites (BGM) feed almost exclusively on grasses, including corn, small grains, and sorghum. Twospotted spider mites (TSM) not only feed on many species of grasses, but also on soybeans, fruit trees, and a variety of vegetables and ornamental plants.
Nebraska grain sorghum producers are being advised to be on the lookout for sugarcane aphids. While this pest hasn't been a problem in Nebraska previously, it is in Kansas and moving north. The sugarcane aphid is light yellow to gray in color, with dark cornicles (“tail-pipes”) at the end of the body and dark tarsi (feet). Adult aphids can be winged or wingless.
The first western bean cutworm moths were captured in University of Nebraska-Lincoln black light traps June 23 at Clay Center, June 27 at North Platte, and June 30 at Scottsbluff. Flights are currently increasing, particularly in North Platte. Scouting should be underway across much of the state.
Accumulated degree-days offer a proven means for estimating when to scout for insects, including the western bean cutworm. Here's how to estimate insect growth and recommended dates to start scouting for WBC at 14 Nebraska sites.