Evaluation of plating date on insect pest in Mississippi soybean

The early soybean production system consist of planting group 3 and 4 soybean in March and April to avoid late season drought stress, insect pressure, and disease problems.  In recent years we have seen a significant drop in cotton acres and increased grain acres in Mississippi. To manage harvest growers in Mississippi have trended away from the early soybean production system, and have planted more maturity group 5 soybean from mid-April through July to help manage harvest.  With these planting dates being delayed later and later, it leaves soybean more vulnerable to late season insect pest such as stink bugs, soybean loopers, and corn earworms.

In 2013 and 2014, seven planting dates of soybean were planted in both the hills and delta regions of Mississippi to quantify the seasonal occurrence of caterpillar pests. Only soybean planted after May 30 reached threshold for caterpillar pests in both years of the study.  Because only the later planting dates reached economic threshold, in 2015 three later planting dates of soybean were used.  Treatments consisted of automatic diamide applications (Prevathon) to simulate Bt soybeans compared to threshold treatments. This paper will address the potential value of Bt soybeans to Mississippi producers and identify seasonal periods of greatest risk from insect pests in soybeans.