Assistance with 2018 European corn borer and corn disease survey requested

Bruce Potter, Bill Hutchison, Ken Ostlie, and Dean Malvick

Overwintering European corn borer
larva in corn stalk.

Entomologists and plant pathologists at the University of Minnesota continue to document and understand changes in European corn borer (ECB) populations and corn diseases in our state.

Each fall, about 150 corn fields are surveyed for the presence of corn borer damages, overwintering corn borer larvae, and corn diseases. During the growing season weekly updates of ECB moth captures in black light traps are made available: https://www.vegedge.umn.edu/moth-data/ecb-info. Funding from the Minnesota Corn Research and Promotion Council has provided us an opportunity to improve these efforts.

Since the widespread adoption of Bt traits in the 1990s, populations of this corn pest have been low. Recently, corn growers have increased the number of acres planted to hybrids without Bt traits (conventional corn) for ECB. Several corn disease have also been noted to be increasing or spreading in the state.

To ensure that insect and disease survey results reflect the effects of these non-Bt and other acres, we need to include a percentage (at least one field/county) of these conventional corn acres in survey efforts for each county. We will also collect overwintering stage larvae from fields where ECB populations are large. These larvae will be reared to determine the prevalence parasites and/or the single generation strain of this insect.

Can you help?

We are looking for cooperating corn growers to help us improve the accuracy of survey efforts for corn insects and diseases. If you would allow us to sample one of your conventional and Bt corn fields this fall, please contact us by August 17 and email Bruce Potter at bpotter@umn.edu with:

• Your name:
• Phone number:
• Field location (GPS or County, Township, Section description of the field):

We will select surveyed fields to provide the best geographic representation of populations. Growers will be advised if their field has a high population of borers but individual field locations and farmer information will not otherwise be shared. Attached are a few examples of 2017 survey results.

Thank you in advance for your support of our research on Minnesota corn pests.

Fig. 2. Corn borer observed in non-random,
non-Bt fields during 2017 survey.
Yellow = tunneling
Red = tunneling with larvae found
White = no observed signs of corn borer

Fig. 3. Incidence of stalk rots in 2017
fall corn borer survey. Hybrids not identified.