Check Corn for Black Cutworm

Virgil Schmitt, Extension field agronomist for Iowa State University (ISU) Extension and Outreach in Muscatine County, says black cutworms are showing up in eastern Iowa. Now is  time to check fields for damage.

Black cutworms do not overwinter in Iowa. Rather, black cutworm moths fly in from the south. If few or no moths fly in, then few or no eggs will be laid, and black cutworm will not be a concern. If a significant number of moths fly in, then there may be enough eggs laid to cause significant loss in a corn field. To monitor incoming flights of black cutworms, a series of traps have been established. Several eastern Iowa counties south of I-80 had significant flights on April 13 - 15, 2014.

Development of black cutworm is based on climatic temperature. Black cutworms develop whenever the temperature is above 51 degrees.

Corn plant with below ground feeding by black cutworm (Photo courtesy of Tom Hillyer)

The black cutworm (near the soil line on the knife blade) that damaged the plant in the previous photo (Photo courtesy of Tom Hillyer)

Schmitt says Tom Hillyer of Hillyer Agriservice in southeast Iowa, has found a few fields with significant injury from black cutworms. See these photos.

All corn fields should be regularly scouted for black cutworm injury until the corn plants reach V5 stage. 

Click here, for more information on black cutworm..
   
Nitrate Tests
Schmitt also recommends farmers take a late spring nitrate test.

The earliest planted corn is approaching the time to check the N status of the soil by taking one-foot depth soil samples when the corn is 6-12 inches tall. At least 16 soil cores (24 is better) should go into each sample and about a cup of this (soil bag full) sent to a lab for analysis. Cores should be pulled in a systematic way going across corn rows (for example, first core pulled in the row, next one-1/8 the distance between rows, next 1/4 the distance between rows, etc.).

For more information on the process of soil testing, click here.

An information sheet for sending samples to ISU is located here.