Growers, Check Corn Stands NOW

June 4, 2009
ICM News

By Jon Tollefson and Erin Hodgson, Department of Entomology

This is a very good time to walk corn fields and check the plant stand. Estimating your plant stand will help you know what plant population actually emerged compared to what you thought you planted. And it will help you scout for early-season insects and disease.

There are several insects that might be decreasing your plant stand right now. We have had reports of dingy cutworms, black cutworms, wireworms, and armyworms. You can still take action against the black cutworms and armyworms. Even though it is too late to treat for wireworms now, finding them in corn fields can help you be prepared for them next year.

Cutting of corn by black cutworms was in progress by the end of last week and should now be happening in central and northern Iowa, as reported in the ICM article Predicted black cutworm cutting dates in corn. This insect can be stopped with foliar insecticide sprays. A recent ICM Newsletter article, Dynamic BCW Action Threshold, provides calculation aids for the treatment thresholds that should be used.

To scout and control armyworms, read the ICM News article on armyworms. The recent stalk bore article will help you prepare to watch for stalk borer if they begin to move into your field.

Update on wireworm presence in Iowa

An unexpected event with the wireworm in Iowa and surrounding states is that they have caused stand loss in fields of corn where the seed had been treated with Poncho 250. If you have planted seed with a Poncho treatment, don't ignore it. If there is stand loss from wireworms in those fields you might consider going to the higher rate (Poncho 1250) next year or to treat the fields with a granular insecticide instead.

cut corn


Jon Tollefson is a professor of entomology with responsibilities in research and extension. He can be reached at (515) 294-8044 or Erin Hodgson is an assistant professor of entomology with extension and research responsibilities. She can be contacted by email at or phone (515) 294-2847.


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on June 4, 2009. The information contained within may not be the most current and accurate depending on when it is accessed.


Erin Hodgson Professor

Dr. Erin Hodgson started working in the Department of Entomology, now the Department of Plant Pathology, Entomology, and Microbiology, at Iowa State University in 2009. She is a professor with extension and research responsibilities in corn and soybeans. She has a general background in integrated...