Wheat Pest Status March 27, 2015
Over the past few days I have been making spot checks in some of our Hale, Swisher, and Floyd County area wheat fields on the way to the office. All but the latest planted fields are now jointing, in decent shape, and will be looking for some moisture soon. There is still quite a bit of insect activity in these fields and some potential for pest problems to keep a close eye on. The greenbugs seem to be the largest threat at this time but there are plenty of other aphid species in this wheat. I still have not found any Russian wheat aphids but, in speaking with a few area crop consultants, there are a very few in the area. Dr. Ed Bynum, District 1 Entomologist, is consistently finding them and greenbugs in a little heavier population than us in his area to our north.
To me, our greenbug population seems to be trying to increase during the warm weather we have been having. The aphid will typically move up the plant to more tender and sensitive areas during better weather and becomes very active in feeding. Once that happens, the aphid is also more likely to begin reproducing heavily. In the fields I have been watching, the predator and parasitoid population is holding the greenbugs in check. The potential and conditions are certainly right for a pest outbreak area wide. It is more likely that in a fair number of area fields the greenbugs could outpace the beneficial insects. Our area crop consultants have also made me aware of a few fields that have reached economic levels for greenbugs that have been treated already this week. The only way to determine if your field is nearing pest problems is thorough and educated scouting.
Action Threshold Table for Greenbugs
Plant Height (inches) Number of Greenbugs / linear foot
3 – 6 100 – 300
4 – 8 200 - 400
6 – 16 300 – 800