Managing stink bugs in cotton using strip spray applications

Phytophagus stink bugs are an economic pest of cotton production in the southeastern United States.  Important species in this region include the southern green stink bug, brown stink bug and green stink bug. Nymphs and adults feed on developing cotton bolls thereby causing boll abscission and stained lint. Under currently recommended practices, growers manage this pest complex using whole field applications of organophosphate and pyrethroid insecticides, with up to three applications per growing season.  Unfortunately, these applications also kill natural enemies and may flair secondary pest outbreaks.  In a two year study, we investigated the feasibility of applying alternating strips of insecticide compared to a conventional whole field application.  Trials were conducted on commercial farms at multiple locations in Georgia, North Carolina and South Carolina. In each field, predetermined sampling points at a density of one sampling point per 0.4 ha were established in a grid and recorded using GPS coordinates.  There were a similar number of observations in treated and untreated areas of strip sprayed fields.  At each sampling location, stink bug density and internal boll damage were estimated weekly for six weeks starting at anthesis.  When estimates of internal boll damage exceeded the Extension recommended treatment threshold, insecticides were applied using either the strip or conventional method.  Response variables were analyzed using SAS 9.2 and geostatistical techniques in ArcMap 10 (ESRI).  Results suggest that the strip spray method provided similar levels of stink bug suppression compared with the whole field applications.