Assessing stink bug-induced injury on soybean seed

During the previous decade, Louisiana soybean IPM strategies have been evolving in response to the adoption of novel agronomic practices and emerging pest problems. Current action thresholds (AT) for stink bugs in Louisiana have not considered that earlier maturing indeterminate varieties (MG III and IV) are now being planted on considerable acreage in Louisiana. There may be differences in injury produced by stink bugs, especially with the redbanded stink bug, compared to that in the older determinate soybean varieties that were historically grown in the South. In addition, there are no considerations in the AT for seed quality effects produced by stink bug feeding. The objective of this project was to develop a protocol to isolate stink bug feeding at the pod level to compare injury potential among stink bug species and between species at selected soybean pod/seed maturities. Procedures of this protocol were successful in measuring rates of physical seed injury and yield (mature seed weights) among multiple stink bug species. Consistent and repeatable soybean pod and seed damage was obtained with artificial infestations for all species and pod/seed maturities. This protocol was sufficiently sensitive to record maximum damage on immature and mature seed after only 72 h of infestation. Results from these no-choice artificial infestations were similar to injury produced by native stink bugs in a field environment. Results of this study will provide vital information to improve current soybean IPM recommendations.