Damage by Rice Stink Bug to Grain Sorghum12

Abstract

Although Oebalus pugnax (F.) fed on stems, rachis branches, and glumes of grain sorghum, they were primarily seed feeders. Seeds damaged by rice stink bugs were smaller and lighter in weight than undamaged seeds. The percentage of seeds per panicle with feeding punctures and the number of punctures per seed generally increased as infestation levels of rice stink bug increased. Bugs reduced grain yield and percent seed germination, but reduction levels varied, depending on the number of bugs per panicle and infestation period during grain development. Bugs caused more seed damaged during early grain development. Larger reductions in yield occurred when 16 rice stink bugs were maintained on panicles from the milk stage of grain development to maturity (28 days) than when they were maintained on panicles from the soft-dough stage to maturity (20 days). Yield was not significantly reduced when 16 bugs infested panicles during the last 10 days of grain development, but small reductions occurred in percent germination. Reductions in yield which occurred when panicles were infested by rice stink bug during the anthesis stage of grain development were due to reduced numbers of seeds per panicle. Later infestations of bugs generally reduced weight but not number of seeds per panicle.