Insect Update for Northeast Nebraska

Western bean cutworm moth flights have been very high and producers should be scouting for egg masses and small larvae in silks. In the northeast some treating should begin very soon, within the next couple of days.

Grasshoppers are very scattered with many areas receiving above average rainfall with very few hoppers. However, I have a plot near Center, which is averaging between 50 to almost 100 grasshoppers per 10 sweeps of a net (about 15-20 per square yard). Most producers are ignoring them because the good vegetative growth has “kept up” with the hopper feeding. Some adults are now being seen and most grasshoppers are in the 4 th and 5 th instars, meaning any attempts at chemical control should use the highest labeled rates available for the crop.

Spider mites have not been reported, the weather overall has not been good for them in corn (moderate temperatures and high humidity). However, these critters work differently in soybeans and they could show up at any time. More on spider mites in next week's issue.

Soybean aphids are present and lurking. If you look hard enough, you could probably find them in nearly every field. Most fields have small numbers although a couple of fields in northeast Nebraska have been reported to be over 100 per plant. This is not yet at threshold level (250 per plant) and weather will play an important part in what will happen through August. The high temperatures early in the week may have slowed them down but cooler temperatures are predicted and this could cause a rise in populations. Growers should be scouting their fields every 3-4 days to keep up with the rapid growth potential of this insect. (KJ)