Prey selection of an insect omnivore in a changing High Plains environment

Successful crop production in the Midwestern High Plains currently depends on the extensive Ogallala Aquifer for irrigation.  However, crops that require high intensity irrigation are quickly exhausting this once dependable water source. Farmers can help conserve this aquifer’s dwindling supply by selecting crops that continue to be profitable under low irrigation treatments. Cotton has proven to fit this criterion by using one-third the amount of water required to grow other major crops, such as corn and soybeans, which struggle to be profitable without substantial water application. Furthermore, cotton can tolerate high temperatures and drought conditions, which are becoming more typical in western Kansas. Early-season arthropod pests feeding on cotton include the twospotted spider mite (Tetranychus utricae) and the western flower thrips (Frankliniella occidentalis), both of which cause the most damage during young plant development. The omnivorous western flower thrips alternates feeding on cotton and the eggs of twospotted spider mites.  If thrips spend more time as a predator of these herbivorous mites under drought conditions their value as a naturally occurring biological control agent would increase. Other effects of drought stress could result in either an increase or decrease in cotton stress. Our project aims to evaluate the direct and indirect effects of drought on plant quality of cotton and the population dynamics of thrips and spider mites. Findings from this project will help cotton growers in the High Plains develop a pest management strategy to effectively reduce damage from arthropod pests, particularly under water-limited conditions.