Impact of rice stink bug (Oebalus pugnax) infestation timing on rice yields

Field cage experiments were conducted in 2010 and 2011 in Stoneville, MS to evaluate the impact of adult rice stink bug, Oebalus pugnax (F.), in two rice cultivars (‘Cocodrie’ and ‘Wells’) at bloom, milk, and soft dough stages of panicle development. The experiments were in a randomized complete block with 20 replications on individual rice panicles with sleeve cages and four replications on large cages over multiple rice panicles. Insect densities included 1 or 2 O. pugnax on individual panicles and 30 or 60 O. pugnax over multiple rice panicles. Uninfested cages were included in each experiment as the control. Percentage of undamaged kernels, damaged kernels, blank kernels, and yield were evaluated at the end of the season. The sleeve cage experiment showed consistent significant differences in percentage of undamaged kernels, damaged kernels, and percentage of blank kernels for infestation time and infestation density. The large cage experiment showed mixed results for these parameters. Percentage of undamaged kernels yield as measured by weight (g) per 50 panicle sample was significant at the soft dough stage. This study suggests that the bloom and milk stages are the most critical stages of O. pugnax injury that demands intensive scouting.