Lepidopteran pests of soybean—such as the green cloverworm (Hypena scabra), shown here—are growing in importance in the U.S., and a pair of articles in the Journal of Integrated Pest Management provides updated guidance on biology, distribution, and management options for five leading caterpillar pests of soybean. (Photo by Adam Varenhorst)

By Erin Hodgson, Ph.D., and Anders Huseth, Ph.D.

Anders Huseth, Ph.D.

Erin Hodgson, Ph.D.

There never seems to be a dull summer when you’re an extension entomologist of field crops. Like Coolio said, there is always “sumpin’ new” happening in agriculture. Fluctuating pest populations and invasive species make our jobs interesting. Add in new chemistries and technology updates, and it’s hard to keep up with everything.

When a pest does establish and become a problem, we want to provide accurate identification and timely management recommendations. Unfortunately, many of our tried-and-true resources are becoming out of date. New extension folks have been especially frustrated by a lack of current resources. In particular, there is not enough current information on caterpillars feeding in soybean, though these pests are becoming more economically important in the U.S. and around the world. So, a few of us decided to create an update for some of the most prominent species in U.S. soybean. We represent five states spread across the nation: Florida, Iowa, Louisiana, Minnesota, and North Carolina.

A survey of field crop entomologists in soybean-growing states indicated five species of highest concern: green cloverworm (Hypena scabra), soybean looper (Chrysodeixis includens), corn earworm (Helicoverpa zea), velvetbean caterpillar (Anticarsia gemmatalis), and painted lady (Vanessa cardui, also known as thistle caterpillar in its larval form). Shown here are maps indicating where each pest has appeared and how growers rate its persistence. (Image originally published in Huseth et al 2021, Journal of Integrated Pest Management)

Lepidopteran pests of soybean—such as the corn earworm (Helicoverpa zea), shown here—are growing in importance in the U.S., and a pair of articles in the Journal of Integrated Pest Management provides updated guidance on biology, distribution, and management options for five leading caterpillar pests of soybean. (Photo by Winston Beck, Iowa State University)

Lepidopteran pests of soybean—such as the painted lady (Vanessa cardui, also known as thistle caterpillar in its larval form), shown here—are growing in importance in the U.S., and a pair of articles in the Journal of Integrated Pest Management provides updated guidance on biology, distribution, and management options for five leading caterpillar pests of soybean. (Photo by Erin Hodgson)

To start, we surveyed field crop entomologists in all soybean-growing states to better understand current pest occurrence and abundance in soybean (approximately 83 million acres). We compiled data from all 31 soybean-producing states during the winter of 2020. Data indicated five species that consistently bubbled to the top of the list: green cloverworm (Hypena scabra), soybean looper (Chrysodeixis includens), corn earworm (Helicoverpa zea), velvetbean caterpillar (Anticarsia gemmatalis), and painted lady (Vanessa cardui, also known as thistle caterpillar in its larval form).

After summarizing survey information, we decided to write profiles on these species to improve identification, distribution, and scouting guidelines. Our group used older research and recent field observations to develop profiles of these key pests. Last, we wanted to focus on management, especially highlighting insecticide resistance issues starting to become prominent in some states. The results of this work are shared in two articles published earlier this year in the Journal of Integrated Pest Management—one on identification and biology and another on distribution and population persistence—with a third article still in the works.

Results from our survey provide a contemporary assessment of distribution and persistence of lepidopterans in soybean. Like the aforementioned rap artist says, field crop extension entomology is a “fantastic voyage,” and we hope the articles help provide updated information for caterpillar identification and management.

Erin Hodgson, Ph.D., is a professor and extension entomologist at Iowa State University. Email: ewh@iastate.edu. Anders Huseth, Ph.D., is an assistant professor and extension specialist at North Carolina State University. Email: ashuseth@ncsu.edu.