| Summary: | Numerous arthropods are pests of soybean in the subtropical environment of Louisiana. The most important pod-feeding guild includes a complex of stink bugs (Hemiptera: Pentatomidae). One of these species, redbanded stink bug (Piezodorus guildinii [Westwood]), has emerged as a significant pest in Louisiana soybean. Currently, limited information is available describing soybean plant injury from this pest in the United States or compares injury relative to native stink bugs. Therefore, a field protocol was modified to assess injury to soybean seeds. Studies conducted in Louisiana during 2009-2011 used procedures to isolate the effects of infestation duration (24-96 h after infestation [HAI]) on seed injury at selected pod stages (R5-R6.5). In addition to redbanded stink bug; seed injury from brown stink bug, Euschistus servus (Say); and E. quadrator (Rolston) also was evaluated. For the infestation duration experiments, all injury to immature seed was significant between treatments (non-infested and infested pods). Injury to immature seed in R5.5 stage pods peaked (P=0.0102) by 72 HAI for redbanded stink bug. Injury to immature seed in R5 stage soybean pods peaked (P=0.0084) by 96 HAI for brown stink bug. For mature seed injury and weights significant differences (P<0.0001) between non-infested and infested pods were detected for all species. A second experiment evaluated seed injury among pod stages (R5-R6.5). Immature and mature seed injury was not significantly different (P>0.05) among pod stages for any species. Weights of mature seed were significantly lowest for redbanded stink bug (P=0.0177) and E. quadrator (P=0.0261) infestations during the R5 and R5.5 stages. Based upon mature seed weights similar levels of injury were produced by native infestations and caged stink bugs. Non-injured seed did not compensate for injured seed within the same pod. These results add to our understanding of stink bug-induced seed injury during selected pod stages and will allow further improvement to Louisiana soybean IPM recommendations.
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