Soybean aphid update

As reported last week in the ICM Newsletter, soybean aphid infestations have been discovered in Iowa. A few fields were treated last week in southeast Iowa. Although the presence of soybean aphid infestations in Iowa is nothing new, the earliness in the season is a surprise.

Because of this reported treatment, producers across Iowa started looking in their fields in earnest for aphid problems. One week later, we have had reports of low population infestations from Boone and Crawford counties. Aphids are present in many parts of Iowa, but to date only an extremely small number of fields have developed economically significant populations, as we reported in last week's ICM Newsletter article. Diligence in watching fields for aphids and other pests is wise, but again, producers shouldn't panic.

Aphids are continuing to be an enigmatic pest. On Monday, June 14 two field crop specialists reported cases where producers had mistakenly misidentified another insect, soybean thrips that were scarring leaves and thought they were soybean aphids. Soybean thrips are tiny sucking insects, about 1/16 inch long--smaller than aphids--and are not much of a threat even though they might be the most common insect found in a soybean field. Again, the first key to integrated pest management requires is to correctly identify pests when scouting in order to make effective management decisions.

Both winged and wingless soybean aphids can occur on a soybean leaflet.

For more information on aphids review past issues of the ICM Newsletter or visit the Plant Health Initiative website. Learn more about thrips by going to the University of Illinois Extension website.

This article originally appeared on page 73 of the IC-492(12) -- June 21, 2004 issue.

Updated 06/20/2004 - 1:00pm