Dynamics and seasonal abundance of stink bugs (Heteroptera: Pentatomidae) in a cotton-soybean ecosystem.

Abstract

Two soybean varieties (early-maturing group V and late-maturing group VII) and two cotton varieties (conventional and transgenic (Bt) were grown in adjacent replicated large field plots (approximately 0.1 ha each) at two locations for 3 yr. The dynamics and relative abundance of phytophagous stink bugs within these two crops were observed. The most abundant pentatomid species in both crops for all 3 yr were Nezara viridula (L.), Acrosternum hilare (Say), and Euschistus servus (Say). Several other species also were commonly collected. This is the first record of Mormidea lugens (F.) on soybean and E. quadrator Rolston, E. obscurus (Palisot), Holcostethus limbolarius (Stål), and Oebalus pugnax (F.) on cotton. Stink bugs began arriving in soybean when plant growth stages ranged from pod formation to full seed development. Peak numbers of these insects were found in soybean from the time of full-size seeds in the pods until early maturity. The bugs were first attracted to the earlier maturing cultivar (group V), where they remained until plants began to mature (R7). The pentatomids then moved to the later-maturing cultivar (group VII) as it reached full pod to full seed. Stink bugs began arriving in cotton from the time of the earliest flowers until after the first bolls formed. Peak numbers in cotton occurred during the time when all stages of developing bolls were present. Stink bug numbers were much greater in soybean than in cotton over all three seasons. This preference for soybean over cotton indicates the potential use of soybean as a trap crop for attracting stink bugs away from cotton. Additionally, the coordinated use of early- and late-maturing soybean cultivars as a trap crop could minimize the area requiring insecticides, as well as the number of insecticide applications to cotton.