Soybean plant response to Dectes texanus infestations under field conditions

The soybean stem borer, Dectes texanus Leconte (Coleoptera: Cerambycidae) is a species native to North America that has recently become an important pest in Kansas soybean (Glycine max L.). Larval tunneling and development within the main stem has been reported to cause a decrease in seed weight by 7-11%, where one larvae per plant can cause up to 10% yield loss. Although yield loss has been examined for this pest in other states, there is a lack of information on yield loss seen in Kansas soybean production fields as well as other effects infestation by D. texanus may have on the soybean plant. The objective of this study was to examine the soybean plant response to natural and artificial D. texanus infestations with different densities of soybean stem borers (stem feeders). During 2013 and 2014, two experiments were conducted within soybean production fields: 1) a cage study using 50 whole-plant exclusion cages that were artificially infested with D. texanus adults, and 2) an open plot study that allowed for natural colonization of soybean by D. texanus. Measurements of plant height, stem diameter, and number of D. texanus entrance hole were recorded throughout the summer and yield (seed weight per subplot and cage) was assessed at the end of the growing season for both experiments, respectively. Implications from these results on current management strategies will be discussed.