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.
Erin Hodgson Professor
Dr. Erin Hodgson started working in the Department of Entomology, now the Department of Plant Pathology, Entomology, and Microbiology, at Iowa State University in 2009. She is a professor with extension and research responsibilities in corn and soybeans. She has a general background in integrated...