We are starting to see an increase in defoliation from insects in some soybean fields around the state. Basically these insects can be broken down into two distinct groups; “foliar feeders” and “pod feeders”. Fall army worm has been observed in some fields. The distinct identifying characteristic of fall armyworm is the inverted “Y” on the head capsule. Fall armyworm can quickly do damage that results in yield loss. The general rule of thumb for fall armyworm and other foliar feeders is the following:
Treatment is recommended when foliage loss is around 15-20% during pod fill. However, if pods are filled defoliation losses can be 35-40% before the treatment threshold is reached.
The other insect that has been observed in some fields is corn earworm, which can feed directly on pods and greatly reduce yield potential. Control of corn earworms is suggested if you find two or more per row-foot.
With the high yield potential we still have in some of our soybean fields and the price of soybean make sure you continue to scout for pest problems.
Treatment information can be found at the following link:
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2347/EPP-7167web.pdf
