Dectes stem borer management

Infestations of the soybean stem borer, Dectes texanus, were first reported in Edwards, Barton, Kiowa, Ford and Pawnee counties in 1985 (Buschman and Sloderbeck 2010). Borer larvae cause severe lodging problems in north-central and southwestern Kansas, where infestations of 50 to 80 % of plants with tunneling are common (Sloderbeck et al. 2003). In Republic Co., some sites have approached 100% infestation. Damaging populations are expanding westward in soybeans and more recently in sunflowers, with infestations reported in an additional 59 counties (Buschman and Sloderbeck 2010). Expansion may be due to reduced availability of alternate host plants such as wild sunflower, increased borer larvae winter survival, increased soybean acreage, or increased adoption of non-tillage practices (Campbell 1980, Buschman and Sloderbeck 2010). Though interest in management and control of soybean stem borer has increased, strategies remain limited. The major goal of this objective is to examine the timing and movement of soybean stem borer and other key soybean pests in Kansas soybean fields and evaluate the use of site-specific pest management practices to mitigate losses from insect pests. Our sub-objectives are to: 1) identify key factors influencing adult pest distribution patterns throughout the season, 2) quantify the influence of non-crop habitats surrounding soybean fields on the timing of colonization and identify key environmental cues for predicting emergence of adult soybean stem borer, stink bugs, and soybean podworm and 3) determine the effectiveness of reduced insecticide applications at mitigating losses by these key pests in Kansas soybean.