The question that is on quite a few farmers minds is do I have aphids and when do I have to or should I spray?
At this point we have found Soybean Aphids, but not at sprayable levels. There are fields close to the Mississippi and Minnesota rivers that are surrounded by woods and buckthorn that have reached sprayable levels, and we have been told that they have been sprayed.
Historically in our area we see sprayable aphid numbers the last week in July, into the first two weeks of August. In my experience I normally see aphids earlier and in higher numbers in fields that are:
- Surrounded by woods and buckthorn
- Have no seed treatment or a low quality seed treatment
- Low potassium soil tests levels
- First or last planted fields.
I differ with many Agronomist as when to spray aphids, my recommendation is if we have higher than normal temperatures and below normal moisture levels I will recommend spraying before threshold.
What I have been seeing in many soybean fields, for the last few weeks which is of concern is Septoria Brown Spot, (pictured below on the left and right)