Even with some cooler temperatures last week, moths were still being reported around the state. True armyworm (TAW) activity was lower during Week 6 than in previous weeks with a total of 40 TAW moths reported across the state. However, black cutworm (BCW) captures increased dramatically last week. In total, 99 BCW moths were reported across the state, which is the highest weekly total of the year.
We predicted cutting dates for BCW based on significant flights that occurred in April in southeast and central Iowa. Additional significant flights occurred in Lucas County and Shelby County on May 6 last week. Based on the projected degree day accumulation, the predicted date of cutting would be similar to our original predictions. Use the estimated cutting dates as a baseline for scouting and continue to scout cornfields until V5 to account for any prolonged arrival of BCW into the area.
Figures 1 and 2 show the total moth captures in each county from May 3 to May 9 for TAW and BCW, respectively.
Follow the links to see reports from Weeks 1 and 2, Week 3, Week 4, and Week 5.
Surrounding states also monitor and report BCW and TAW captures. If you live near the state border, it may be beneficial to check these resources periodically. More resources may be available than what is listed here:
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- Extension Education Specialist, Entomology