MINNEAPOLIS — Scout corn, sugar beets and emerging soybean for black cutworm and other stand problems now. Weather systems bring migrant black cutworm moths into Minnesota each spring and this year is no exception.
The Minnesota Corn Research and Promotion Council has helped support a network of pheromone traps to help determine the risk of damage from this insect in 2017. This year, the trajectory of the low level jets that help bring black cutworm moths and other migratory insects into Minnesota have, for the most part tracked, south and east of us.
There have been three widely scattered but significant flights this spring. Pheromone traps run by cooperators picked up an April 15th flight into Brown and Redwood Counties on April 15, Redwood County on April 29 and Rock County on May 7-8. All other trap reports have been low. This is good news. Degree-day accumulations indicate that larvae from all three flights should be leaf feeding now and larvae from the earliest flight should be large enough to cut corn by May 29.
This year’s black cutworm flights have been very localized. Don’t assume that moths could not have dropped undetected into other localized areas beside than those listed above. Black cutworm attack a wide range of plants. Corn and sugarbeets are less able to compensate for reduced stands than soybean. Row crop stands should be always be scouted as they emerge for stand problems caused by several species of stand reducing insects, seedling disease and planter mishaps.
Some areas of the state are very wet. Hopefully, field conditions in your area allow early scouting without burying vehicles and summer interns. On a more positive note, moist soil usually makes it easier to find cutworm larvae. They tend to spend the day under residue if wet or at the boundary of wet and dry soil when drier. Adequate soil moisture also tends to keep cutting near the soil surface and above the growing point. Corn plants cut off above the growing point usually survive.
Updated information on black cutworm biology, migration, scouting and management advice, descriptions of other cutworm species as well as the 2017 weekly trap capture information is available at Minnesota black cutworm trapping network. A season summary will be available late this week.
I would appreciate hearing about any stand reducing insect problems that you encounter this spring.
— Bruce Potter, University of Minnesota Extension IPM Specialist
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