I’ve been hearing about and seeing a variety of caterpillars in seedling crops this week. In soybean, you notice thistle caterpillars feeding and making webbed cavities from the leaves. They can be easy to find in early-vegetative soybean but rarely build up to economic populations. Read more about thistle caterpillars in this ICM News article.
There can be a lot of green caterpillars in soybean, and you are likely to find some every time you sweep. One active right now is green cloverworm. These slender, pale green caterpillars tend to wriggle violently if handled (compared to other sedentary caterpillars). Defoliation can happen in the vegetative stages, but higher populations tend to happen after bloom. Read more about soybean defoliators in this ICM News article.
There have been a few reports of various cutworms and armyworms in corn this summer. One that I don’t usually hear much about is variegated cutworm. The ash-grey larvae are relatively easy to identify because of the row of pale yellow spots running along the back. This species tends to climb up plants more than other cutworms and can be found on corn whorls.
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 June 14, 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