Several growers have called this week with concerns about insect pressure in soybeans. In several of the fields I visited, stinkbugs were at treatable levels. The picture above is of some small, immature southern green stinkbugs on soybeans in the R6 stage of development. This cluster was a recent hatch out but they mature fast enough to cause injury within a few days. They are relatively easy to control but adults are migrating as other host plants are reaching full maturity. They are looking for the next best food source and these soybeans are a welcome treat to them.
I called Dr. Phillip Roberts, cotton and soybean entomologist with UGA Cooperative Extension. He advised that growers continue to monitor their fields for soybean pests at least until R7 growth stage, when the leaves are turning yellow and the first of the pods on individual plants turn a brown, mature color. Typically our fields will take about another two to three weeks to get to this stage from the R6 growth stage. R6 is when the seeds are filling out the pods and touching each other in the top few positions of the plant.
For later planted fields, we are in earlier stages of development, likely R4 or R5. This will mean we need to keep a close watch on these soybeans as many of our pests will seek out the next available food source as the other crops are drying down.
It is worth noting that different chemicals may be recommended based on the type of stinkbug you have present in your field. Southern green stinkbugs are easier to control than brown stinkbugs because of some insecticide resistance noted in the brown stinkbug population. Consult your county agent or pest management handbook for control options.