We are starting to see dead leaves caused by feeding of soybean stem borer larvae in south central Nebraska soybeans. No control measures are appropriate at this time, but monitor your fields and be aware that high populations of soybean stem borers may predispose the field to lodging and make harvest difficult.
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.
Western corn rootworm beetles began emerging in southeast and south central Nebraska during the last week in June. Beetles typically emerge somewhat later in northeastern and western Nebraska. Scouting should be underway to determine field presence and possible need for treatment.
Japanese beetle adults are beginning to emerge in eastern Nebraska and have been reported feeding in corn and soybean. Here's how to differentiate them from the look-alike sand chafers and treatment thresholds to determine when treatment is recommended.