Colonization preference of Euschistus servus and Nezara viridula in transgenic cotton varieties, peanut, and soybean

Producers of Bt cotton, Gossypium hirsutum L. (Malvaceae), in the southeastern USA face significant losses from highly polyphagous stink bug species. These problems may be exacerbated by crop rotation practices that often result in cotton, peanut, Arachis hypogaea L., and soybean, Glycine max (L.) Merrill (both Fabaceae), growing in close proximity to one another. Because all of these crops are hosts for the major pest stink bug species in the region, we experimentally examined colonization preference of these species among the crops to clarify this aspect of their population dynamics. We planted peanut, soybean, Bt cotton, and glyphosate-tolerant (RR) non-Bt cotton at three sites over 3 years in replicated plots ranging from 192 to 1 323 m2 and calculated odds ratios for colonization of each crop for Nezara viridula (L.) and Euschistus servus (Say) (both Hemiptera: Pentatomidae). In four of five experiments, both E. servus and N. viridula preferred soybean significantly more often than Bt cotton, non-Bt cotton, and peanut. Neither N. viridula nor E. servus showed any preference between non-Bt and Bt cotton in any experiment. Both species had higher numbers in Bt and non-Bt cotton relative to peanut; this was not significant for any single experiment, but analyses across all experiments indicated that N. viridula preferred Bt and non-Bt cotton significantly more often than peanut. Our results suggest that soybean in the landscape may function as a sink for stink bug populations relative to nearby peanut and cotton when the soybean is in the reproductive stage of development. Stink bug preference for soybean may reduce pest pressure in near-by crops, but population increases in soybean could lead to this crop functioning as a source for later-season pest pressure in cotton.