Integrated Crop Management

Black cutworm scouting dilemma

Each year we coordinate a trapping program across Iowa for black cutworm adults (moths) that migrate into the state. The company from which we purchase our black cutworm trapping supplies, unfortunately, sent pheromone that was improperly mixed and therefore not attractive to the male moths. We did not learn of this problem until after the moths had already begun their migration into Iowa, and then it was too late to get new pheromone and have it redistributed.

On the positive side, Tracy Cameron, Crestland Co-op, operated several traps in Taylor and Union counties that used pheromone supplied from last year's trapping program. These trap catches will give us an accurate prediction for southwestern Iowa. However, for the rest of the state the bad pheromone creates a dilemma in that we will not have an accurate forecast that predicts calendar dates when initial cutworm cutting should begin. The best that we can do is use data from neighboring states and extrapolate to Iowa. Predicted scouting dates in central and northern regions of Iowa are very tentative.

[1] Black cutworm moth (adult).

The predicted cutting dates are as follows: southwestern Iowa (May 15), southeastern Iowa (May 16), and east central Iowa (May 16). Producers and field scouts to the north of these areas should begin scouting around May 18. These predicted dates assume average temperatures during the week of May 10-16.

This article originally appeared on page 61 of the IC-482(10) -- May 17, 1999 issue.

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