Insects
Insect pests may cause direct and or indirect injury to crops. Get more information on key insect pests in Iowa, how to scout for them, and how to implement integrated pest management tactics that utilize economic thresholds to know when action is warranted and minimize the spread of insecticide resistance.
Timely Insights on Insects
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May 18, 2025Content Author
The week of May 11 – May 17, 2025 was another relatively quieter week for both black cutworm and true armyworm moth across the state.
A total of 33 black cutworm (BCW) moths were reported last week, with no significant flights being reported. As a reminder, now is the time to be scouting for black cutworm based on our predicted cutting dates from previous significant flights from earlier this spring combined with growing degree days. .
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May 12, 2025Content Author
Compared to the previous weeks, the week of May 4 – May 10, 2025 was a much quieter week for both black cutworm and true armyworm moths across the state.
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May 6, 2025Authors
Black cutworm (BCW) is a migratory pest that arrives in Iowa each spring. We monitor moth activity around the state with our Iowa Moth Trapping Network, and there has been quite a bit of BCW moth activity this spring. The female BCW moths lay eggs in and near crop fields. The eggs hatch and the larvae can feed on corn leaves or even cut corn seedlings. Larvae must attain a certain size (4th instar) to be large enough to cut corn plants, and cutting can occur until plants reach the V5 stage. We predict when BCW will big enough to cut corn plants based on growing degree day data and the occurrence of significant flights.
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May 4, 2025Content Author
This last week (April 27 – May 3, 2025) was a another relatively active week for moth activity across the state for both black cutworm and true armyworm moths.
A total of 107 black cutworm (BCW) moths were reported last week. Three reports included significant flights: Story County (April 27), Lucas County (April 28), and Pottawattamie County (April 29).
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April 30, 2025Authors
Bean leaf beetles overwinter as adults (Figure 1), which are susceptible to cold weather, and most will die if exposed to air temperatures below 14°F. They avoid harsh temperatures by burrowing under plant debris and loose soil. In early spring, the adult beetles migrate to available hosts, such as alfalfa, tick trefoil, and various clovers. They are strongly attracted to soybean. Adults move locally in the landscape to soybean fields with emerging seedlings. While initial adult activity can begin before soybean emerge, peak abundance often coincides when the early-planted soybean fields start to emerge, leaving those fields prone to defoliation.
