Duration of rice stink bug (Oebalus pugnax F.) infestation impact milk stage of panicle development

Field experiments were conducted in 2011 and 2012 at the Delta Research and Extension Center, Stoneville, MS to determine the impact of duration (days) of O. pugnax infestation during the milk stage of panicle development with sleeve cages (20 x20 cm). The study was a randomized complete block with 2 (cultivars) by 5 (days) factorial arrangement on one insect density per panicle with uninfested controls tested under field conditions. Females and females were included as test factors. All infestations were conducted during the milk stage of panicle development. Response variables were subjected to arcsine transformation before analysis of variance (PROC-MIXED). Means (±SEM) were calculated with LSMEANS and separated by Fisher’s Protected Least Significance Difference at α = 0.05. Percentage of grain yield per panicle decreased with increased duration of O. pugnax infestation, while percentages of blank and damaged kernels significantly increased with increased duration of O. pugnax infestation. Males and females caused substantial grain yield and quality losses, but females caused more injury compared to males. The amount of kernel injury significantly increased from day 1 to day 5 of O. pugnax infestation, declining after day 5 to day 7. Panicle stage and duration of infestation determine O. pugnax injury.