Moth trapping begins in Iowa

April 19, 2019 5:00 PM
Blog Post

Each year, Iowa State University’s IPM team monitors field crop pests to help inform farmers and scouting personnel about pest activity in Iowa. This year, our moth trapping network includes black cutworm (BCW) and true armyworm (TAW), two migratory pests of crops in Iowa that are unpredictable year to year and thus require monitoring.

BCW and TAW moths and larvae
Top left: black cutworm moth. Bottom left: black cutworm larvae. Top right: true armyworm moth, photo by Whitney Cranshaw, Bugwood. Bottom right: true armyworm larvae.

To aid in this effort, we ask for volunteers around the state to establish trapping locations and report their findings. This year, we established 45 BCW and 45 TAW locations in 32 Iowa counties (Fig. 1) with the help of 8 ISU research farms and 34 private volunteers.

TAW trap
Armyworm moths trapped in a wing style pheromone trap.

Moth trapping counties
Figure 1. Counties with moth trapping cooperators in 2019.

These volunteers allow us to accurately refine pest movement into the state and estimate scouting and treatment windows for growers based on intensive flights. An intensive flight for black cutworm moths occurs when 8 or more moths are captured in a pheromone trap over two nights. No such threshold exists for true armyworm moths yet, but monitoring is done to confirm presence in an area and support scouting activities.

No intensive flights have occurred for black cutworm yet, but moths of both species have been captured in several counties (Tables 1 and 2). As the trapping season continues, additional reports of moth captures will be provided. Ultimately, cutting dates for black cutworm will be predicted and provided in May following any intensive captures reported by our cooperators.

BCW captures
Table 1. 2019 black cutworm trap captures.

TAW captures
Table 2. 2019 true armyworm trap captures.

Surrounding states also monitor and report findings of BCW and TAW. If you are near the state borders, it may be beneficial to check these resources periodically. Some state resources are listed below, but others may be available online soon:


Ashley Dean Agriculture and Natural Resources Extension Specialist II

Ashley is an education extension specialist for field crop entomology at Iowa State University. She coordinates the Iowa Moth Trapping Network, the Regional Corn Rootworm Monitoring Network, and the Iowa Pest Alert Network. She also develops educational resources for field crop pests in Iowa and ...

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...

Adam Sisson Extension Specialist

Adam Sisson is an extension specialist with the Iowa State University Integrated Pest Management (IPM) program and a Certified Crop Adviser. Sisson focuses on the development of publications and other educational resources for farmers, agribusi...