Then input the peak flight date for the first set of dates and today’s date for the second set before clicking on the “Make Plot” button. Make sure the “Iowa Long Term Climate Sites” is selected for Available State and “Growing Degree Days (base=50)” for Select Parameter. Next, use this degree day calculator to determine when 300 degree days is approaching for your area based on any nearby peak BCW flights. Reported black cutworm peak flight dates from April 1 through in Iowa. The reported peak flights in Iowa from April 1 thus far are below (Table 1), and we will continue to post new peak flight updates as they arrive to the Integrated Crop Management Blog. This year, however, we are reporting peak flights by county and providing degree day resources for more local cutting prediction dates using actual accrued degree days for a specific location. Generally, we use moth capture data to predict cutting dates for the nine climate divisions/crop reporting districts in Iowa. Cooperators started checking traps in the beginning of April, and the first BCW moth was captured in Woodbury County on March 24. To find out when moths arrive in Iowa, cooperators around Iowa monitor pheromone traps and report moth captures. A peak flight for BCW is defined as capturing eight or more moths over two nights in a wing style trap baited with a pheromone lure. Degree days are a measure of temperature used to gauge the developmental progress of the insect.

When to scout for BCW caterpillars is based on the accumulation of degree days after a “peak flight” of moths occurs. Scouting is essential to determine if an insecticide application will be cost effective as these pests are sporadic in nature. Emerging BCW larvae feed on winter annual weeds, cover crops and seedling corn leaves. Minnesota has also reported few captures this year, so Iowa is not the only state avoiding major moth flights so far in 2017.īlack cutworm moths arrive in Iowa with spring storms and lay eggs in and around fields. Despite what is being observed in states to the east (Illinois, Wisconsin and Indiana), there have been relatively few captures in Iowa.

This is the time of year when calls about black cutworm (BCW) scouting dates start to roll in, especially when Corn Belt states to the east have reported high moth numbers in traps.

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