Submitted to: USDA Annual Food Safety Research Planning Meeting
Publication Type: Abstract only
Publication Acceptance Date: 12/3/2010
Publication Date: 12/11/2010
Citation: Zeilinger, A., Olson, D.M., Ruberson, J., Andow, D. 2010. Stink bug host preferences: colonization, oviposition, and feeding on cotton.. USDA Annual Food Safety Research Planning Meeting. USDA-Agriculture and Food Research Initiative (AFRI). San Diego. December 11, 2010.. Interpretive Summary: To investigate the causes of stink bug outbreaks on Bt cotton in southeastern US, we are parameterizing a landscape patch model, and conducting competition experiments between bugs and caterpillars in cotton. A key set of parameters is colonization preferences of the stink bugs when the cotton habitat is just beginning to be attractive. We conducted experiments to estimate relative preferences for cotton, peanut and soybean. In general, bugs preferred soybean over cotton and cotton over peanut, but plant phenology and natural enemies in peanut complicate this picture. We conducted competition experiments to evaluate mechanisms other than resource competition (which we have determined to exist at small spatial scales). We allowed caterpillars to damage a cotton plant and measured oviposition and feeding preference of bugs for damaged and undamaged plants. Females preferred to oviposit on undamaged plants, and nymphs preferred to feed on undamaged plants.
Technical Abstract: Relative colonization rates of stink bug species among host crops grown in the Southeastern US are needed to parameterize a landscape model that seeks to predict stink bug populations in Bt cotton. We sampled stink bugs in Bt cotton, non-Bt cotton, soybean and peanuts over 3 years and 3 sites in the region. Both Southern green and Brown stink bugs strongly preferred soybean over all other crops, no preference for Bt and non Bt cotton was found for either species, and Southern green stink bug preferred cotton over peanuts. These results suggest that colonization preference may be a factor causing stink bug populations to shift around the landscape. The potential for stink bug and Heliothine caterpillars competing for resources in non Bt cotton was also examined to determine if competitive exclusion may be a mechanism underlying stink bug outbreaks in Bt cotton. Various greenhouse experiments with and without stink bug and Heliothine caterpillars were conducted. Feeding by heliothine caterpillars reduced stink bug oviposition and demonstrated asymmetrical interspecific competition. Brown stink bug nymphs were sensitive to damage by heliothine caterpillars, while Southern green stink bug nymphs were not. Brown stink bug nymphs preferred to feed on cotton damaged by H. virescens and Brown stink bug nymphs preferred to feed on cotton not damaged by H. zea. Feeding by heliothine caterpillars has complex effects on nymph feeding preferences.