Do Insecticide Seed Treatments Provide any Value on Late Planted Soybeans?
Due to the rain and cold weather this spring a much larger percent of the soybean crop will be planted later than normal. There have been several questions lately about whether or not we should still include an insecticide seed treatment on late planted soybeans. I dug through all my old data trying to separate out trials based on planting dates. I only can speak for my data in Mississippi but generally the average yield response did not vary much based on planting dates.
Also, Dr. Normie Buehring Extension Agronomist at the Northeast MS Research and Experiment Station conducted a 3 year study where he compared maturity groups with and without insecticide seed treatments in April, May, and June plantings in Stoneville, Starkville, and Verona. In short, the average response was about 2.4 bushel yield advantage for the insecticide seed treatment regardless of the maturity group, location, or month planted. In addition, the average response did not change much based on yield potential as well.
It’s often been quoted that the real advantage to insecticide seed treatments on soybeans is on the earliest planted soybeans. That may be true in some instances because early planted soybeans are generally subjected to much more stressful conditions and slow growth, any additional stress by insect pests often compound the problem, however, my data would suggest the benefits are there even for later plantings. In fact, our late planted soybeans are often subjected to the worst threecornered alfalfa hopper main stem girdling. Seed treatments are not perfect against this pest but they certainly do reduce girdling.
Below are a few slides from several years ago comparing planting dates and yield from insecticide seed treatments in soybeans. Most of the data slides are labeled “before or after” April 15th. Not all, but most of the ones that are after were planted some time in May.
Click on Slides to Enlarge
Threecornered Alfalfa Hopper Data by Dr. Roger Leonard. LSU AgCenter
