After visiting several ISU Research and Demonstration Farms this week, it was evident the abundance and diversity of caterpillars in soybean is ongoing. These species represented several insect families. We easily found 8 species while looking at and sweeping early-reproductive soybean. Of course, thistle caterpillars were easy to find, but the interesting part is we saw a range of ages – from small to big caterpillars. I think it is a combination of first and second generation here in Iowa. We also saw green cloverworm, soybean looper, and alfalfa caterpillar sprinkled throughout the small plots. Although not a big surprise, we found a yellowstriped armyworm, true armyworm, and black cutworm in very low numbers, too. One rarely-seen species that happened to be out in strong numbers was celery leaftier. It builds a webbed nest similar to thistle caterpillar. Overall, populations were low and well under the defoliation threshold of 20%.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 12, 2019. The information contained within may not be the most current and accurate depending on when it is accessed.
- Professor
- Extension Entomologist Specialist
- ANR Crops Team Leader
- Extension Education Specialist, Entomology