Predicting insect outbreaks

Growers often comment along with others in the community, "it has been a hard winter so this should cut down on the insect problems this summer." We wish we could do a better job of predicting insect outbreaks several months in advance but this is not the case. Sometimes insect outbreaks are like predicting the weather several months in advance.

The insect’s ability to reproduce and grow during the spring and summer has more influence than anything else. Insect populations can increase and then collapse dramatically.

Generally, we do not have bad insect pest outbreaks. We have a lot of technology and integrated pest management practices that allow us to use our education to make pest control decisions.

Sometimes we do have perennial threats such as rootworms following corn on corn. But even this may not be as predictable as we would like. For example, at the Graves-Chapple Farm, we have a site where we try to grow rootworms which has been in continuous corn. But rootworm levels have decreased to non-existent because of the wet weather.

Scout crops for signs of any damage and use economic thresholds developed from research to determine if there is a need to control the pest. Especially with insects, beneficial insects, those that feed on crop destructive crop insects, may control the pests. Soybean aphid populations can collapse dramatically as beneficial insects consume these pests as a food source. It is important to know what is happening in your fields.

The Extension Service continues to monitor insects that migrate through the use of statewide trapping network. True armyworms have been migrating in the southwest part of the state and boot-heel has shown to have black cutworm. We will alert you to any major pest out-break in our area.

For more information, contact Wayne Flanary, 660-446-3724 or Heather Benedict, 660-425-6434, Regional Agronomists, University of Missouri Extension.