The trapping season for true armyworm (TAW) and black cutworm (BCW) has come to an end. We appreciate our cooperators for tirelessly checking traps the last two months and reporting their captures so we can provide the most accurate scouting information for these pests. To recap, we had 36 cooperators participate from 34 counties in Iowa. A total of 78 traps (39 of each species) were placed and monitored during April and May. Because of these efforts, we were able to provide weekly updates of moth activity and predict cutting dates for BCW in Iowa.
Last week, our cooperators reported 183 TAW and 84 BCW moths statewide. Most of these reports occurred during the first half of last week. Typically, moth activity is winding down by this time, but this year we saw prolonged arrival of both species into the state. Moths were caught the first week of trapping, and large flights began during mid-April and continued through May.
No additional significant flights of BCW occurred last week. With updated degree day information, predicted cutting dates could extend through June 10 across the state. Continue to scout fields weekly until V5 to account for any prolonged arrival of BCW larvae into the area. If you see BCW larvae or evidence of feeding, please email email@example.com. This can help us refine our predictions in the future.
Figures 1 and 2 show the total moth captures in each county from May 24 to June 1 for TAW and BCW, respectively.
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: