Evaluating larval movement of soybean gall midge (Resseliella maxima Gagné) in soil: Potential insights for research and management

In 2019, soybean gall midge (Resseliella maxima Gagné) was identified as a new pest causing significant injury to soybean in the Midwestern United States. Larvae typically feed at the base of the stem, consuming phloem and xylem tissue before dropping to the soil to pupate and emerge as adults. Field studies have shown that most larvae reside within the top 4 cm of soil, with some as deep as 10 cm. Recent research on the different burial depths of field-infested stems has demonstrated a steady decline in adult emergence with increasing depth. However, it remains unclear whether larvae can move vertically within the soil profile. To address this question, we conducted a series of studies to evaluate the extent of R. maxima larval movement through soil. These findings will help interpret results from the burial study and better understand how different tillage practices may impact field populations.