Time to Check for Aphids

Soybean Aphids Are At Economic Thresholds in Some Area Fields
It is time to be scouting for soybean aphids in area fields. The populations have reached economic thresholds in area fields in northern Nodaway and Atchison Counties last Friday August 15th. The numbers of soybean aphids varied. Not all fields were at economic thresholds so it is important to scout fields carefully.
Early planted soybeans are in the seed fill stage of growth. This is when the seeds are filling the pod cavity. When soybeans completely fill the pod cavity, then the next step then is for soybeans leaves to yellow to turn to maturity. These stages are progressing quickly so please check your soybean stage of growth when making a decision to treat for aphids.
The economic threshold for soybean aphids is 250 aphids per plant which gives you a 5 to 7 day window to control these insects once you reach this threshold.
Soybean aphids are generally found on the underside of leaves and can also be found on the stem of the soybean. The aphids are tiny insects which are hard to see. You may need a hand lens. The insect prefers the cool conditions we have been experiencing and populations are increasing.
For more information, contact Regional Agronomists with the University of Missouri Extension, Wayne Flanary located in Holt County at 660-446-3724 and Heather Benedict located in Harrison County at 660-425-6434.