Tuesday, May 17, 2011

Scout Corn Early for Insect Pests

Black cutworm flights indicated this insect is in the area and some fields have high probability of cutting. Now is the time to examine fields for cutting, especially those fields which have had historically problems. Black cutworms fly in on winds from the south. They do not overwinter in northwest Missouri.
This pest generally attacks localized areas or fields. Generally, the cutting is not wide spread and with dry conditions, the insect will work beneath the soil surface and kill the growing point of corn. Heavy infestations in a concentrated area can injure corn with seed treatments or with transgenic events. It is best to scout fields now and with an insecticide if needed.

The next pest we need to watch for is wireworm. This insect feeds on the corn seed beneath the soil or later attacks the growing point of the germinated corn. This insect often makes a hole in the growing point causing injury. There have been some isolated fields affected by this pest and which need to be replanted. One should use a soil insecticide to control heavy infestations of this pest.
The other corn insect pest we need to watch for is perennial white grub. This grub stays in the soil for more than one year and has a pattern on the raster and damages corn. Annual grubs have hair that are scattered without a pattern and rarely injure corn. Insect injury to corn causing replant situations should have insecticide applied during planting and not rely on a seed treatment insecticide.
For more information, contact Wayne Flanary at 660-446-3724 or Heather Benedict at 660-425-6434, Regional Agronomists, University of Missouri Extension.

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