Incorporation of Biorationals and Trap Crop for Stink Bug Management in Soybeans

Abstract

Stink bugs are one of the most important seed sucking pests impacting soybean production in Louisiana. Exploration of chemicals that exhibit attraction or repellent activities toward this major pest would be beneficial to develop a push-pull strategy against this pest complex. Spinosad and neem are two commercially available natural insecticides that were claimed to have attractant and repellent activities against stink bugs. To test the potential of these chemicals, a series of experiments was conducted to investigate the olfactory, tactile, feeding, and oviposition preference of stink bugs toward different commercial spinosad products and neem. Additionally, two years of field experiments were conducted to evaluate the effect of the chemicals in combination with early maturing soybean as components of a “push-pull strategy” on stink bug populations and soybean damage. Insecticides were tested at concentrations equivalent to recommended field applications. The results showed, in Y-tube assays, the southern green stink bug (SGSB) was significantly repelled by neem and significantly attracted to spinosad. In tactile tests, SGSB consistently avoided media treated with neem, but inconsistently was attracted to media treated with spinosad. In feeding preference experiments, Entrust® showed the strongest feeding stimulant compared to the other spinosad products, while neem (Azatin XL®) showed a considerable feeding deterrence. In oviposition preference tests, SGSB did not show a significant preference or avoidance to oviposition media treated with the tested substances. Field experiments showed early maturing soybean significantly attracted stink bug populations as shown by Cumulative Insect Days (CID), indicating that it has potential to be used as pulling component of the push-pull strategy. Meanwhile, in field conditions, the tendency of stink bugs towards Entrust® and the repellency of neem was not strong enough to give statistical differences. The difference in stink bug populations affected seed production and quality as indicated by the parameters seed weight, percentage of undersized seed, and the percentage of good seed.