Scout Before You Plant!
By Ed Corrigan
As the soil temperatures warm up to the 50 degree mark that is necessary for good corn planting conditions there is one pest you may want scout for before you plant.
Japanese grubs!
The Japanese grubs are the offspring of the Japanese beetles that fed heavily in some of our soybean fields last summer. I visited a number of soybean fields last summer with high Japanese beetle counts of up to 10 beetles per foot of row. In the fields where these high numbers of beetles were found, there is likely a high amount of eggs laid and hatched last fall into grubs. On the average the Japanese beetle will lay a total of 50 eggs in 5 egg clusters. This would mean there could be some real “hot spots” in parts of our bean fields that will be planted to corn. The grubs are very hardy and survival is usually good through the winter. As soil temperatures warm to 50 degrees the grubs will begin to come to the surface and feed. If you have planted corn without any soil insecticide, you could find some areas in each field missing plants due to grubs feeding on the kernels. Bt rootworm corn is susceptible to grub feeding.
If you find a presence of 5 or more grubs per square foot, consider adding a soil insecticide to your Bt rootworm corn acres at half rate.
Begin scouting the soybean fields that had the heaviest Japanese beetle pressures and were not treated with an insecticide last summer for beetles.