Western corn rootworm beetles began emerging in southeast and south central Nebraska this week. Before corn silks emerge, they're apt to feed by scraping the surface tissue, leaving a white parchment-like appearance.
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.
Corn and soybean growers should be scouting for Japanese beetles, which have started emerging in eastern Nebraska. First identified in counties along the state's eastern border several years ago, the beetles were found as far west as Lincoln County in 2016.
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.
UNL Extension Entomology is monitoring crop insect pests (primarily moths) using black light traps at the Haskell Ag Laboratory near Concord, the South Central Ag Laboratory near Clay Center, and the West Central Research and Extension Center near North Platte.
Common stalk borer eggs have hatched throughout Nebraska and scouting should begin when 1300-1400 degree days (DD) have accumulated. Current accumulations range from 500 to 1200 DD.
Palmer amaranth has not been confirmed in conservation plantings in Nebraska; however, the identification and occurrence of Palmer amaranth in CRP fields in Iowa has raised concerns among weed scientists and growers about its spread into conservation plantings in Nebraska and offer some suggestions for growers.
