Dropped leaves in soybean fields indicate soybean stem borers are feeding and causing leaf damage. These insects are expanding their range as a pest of soybeans in Nebraska and now can be found in several counties north of I-80.
Wheat streak mosaic virus (WSMV) problems have been extensive throughout the western Great Plains this year, significantly reducing the yield potential of many fields. A critical key in managing this threat in the next crop is elimination of volunteer wheat. Tillage or chemical weed control should occur at least one month before planting to allow host plants time to dry up and cease being a host.
Growers are reporting finding painted lady caterpillars and silver spotted skipper caterpillars in soybeans. This guide can help estimate leaf defoliation in soybean, key to determining whether treatment is necessary.
Timely control of volunteer wheat and other weeds is key to managing yield loss risk in your 2018 crop. Yield-limiting risk factors affected by weed control include wheat streak mosaic and other diseases, insects (wheat stem sawfly and disease vectors), moisture loss, and increased weed seed production.
University researchers are studying why suspected wheat stem sawflies are being found again this year in Nebraska corn, previously thought to be a non-host. Major yield loss is not expected in corn from this pest.
Populations of immature grasshoppers have been reported in areas bordering crop fields. If you're seeing one of the four species that harm cropland noted here, control may be warranted. Treatment is most effective when grasshoppers are small and still contained in field borders.
Ag professionals across central and eastern Nebraska are reporting insect damage to corn following rye and wheat cover crops, likely from the wheat stem maggot. A recent field survey found stand losses in fields ranged from 2%-30% on a whole-field basis.