Relating rice stink bug (Hemiptera: Pentatomidae) sampling to direct and indirect yield loss in rice

The rice stink bug, Oebalus pugnax (L.), is the most important pest of heading rice in the southern United States. Previous work has quantified direct and indirect rice yield losses of rice stink bug feeding, but no study has directly related rice stink bug densities to the sampled area in rice fields. To estimate direct and indirect yield loss incurred by different densities of stink bugs, one-factor randomized complete blocks with 4 replications were initiated at multiple locations in 2018-2019. The treatment factor consisted of threshold treatments: an untreated control, current standard threshold (5 rice stink bugs per 10 sweeps the first 2 weeks of heading, followed by 10 rice stink bugs per 10 sweeps the second 2 weeks), and 10 rice stink bugs per 10 sweeps throughout heading. Untreated plots yielded peck levels of 2.3%, which was higher than the standard and 10 all-season treatments with similar levels of peck averaging 1.2% and 1.4% peck, respectively. Weekly rice stink bug averages served as a good predictor (R2 = 0.57) of peck, predicting that an average of 10 rice stink bugs would yield 1.5% peck. No relationship between direct rice yield loss and weekly rice stink bug averages was observed. However, peck was a good predictor of milling quality, including total milled rice (R2 = 0.41) and head rice yield (R2 = 0.44). Results from this study confirm the validity of the current Arkansas indirect yield loss threshold of 10 rice stink bugs per 10 sweeps all-season.