Effect of Spray Volume and Active Ingredient Rates on Insecticidal Control of a Rice Stink Bug (Hemiptera: Pentatomidae) Complex in Florida Rice

Although many different insects can be found in rice (Oryza sativa L.) fields in Florida, Oebalus stink bugs (Hemiptera: Pentatomidae) are currently considered the most important pest (Cherry et al. 2018). Green et al. (1954) reported finding four species of stink bugs in rice fields in Florida but gave no information on their relative abundance. Genung et al. (1979) reported that five species of stink bugs could be found in rice in Florida, but no information was given on their relative abundance or seasonal occurrence. Jones & Cherry (1986) conducted the first extensive surveys in Florida rice fields and reported that four species were found, with the rice stink bug, Oebalus pugnax (F.), comprising >95% of the total stink bug population. Oebalus ypsilongriseus (DeGeer) was first observed in Florida rice fields in 1994 (Cherry et al. 1998). An extensive survey in 1995 and 1996 documented the occurrence of O. ypsilongriseus in all sampled rice fields in Florida, where it constituted 10.4% of all stink bugs collected (Cherry et al. 1998). Another species, Oebalus insularis (Stal), was first observed in rice fields in Florida in 2007 (Cherry & Nuessly 2010). An extensive survey in 2008 and 2009 reported that it occurred in all rice fields sampled in Florida and constituted 20% of all stink bugs collected (Cherry & Nuessly 2010). Data from these studies show that O. ypsilongriseus (a well-known pest of rice in South America) and O. insularis (a well-known pest of rice in the Caribbean islands, Central America, and South America) are now widespread in rice fields in Florida. The studies were also the first reports of the two species being found in commercial rice fields in the United States. Currently, the stink bug complex infesting rice in Florida is the most diversified and unique in the United States. Cherry et al. (2018) determined the efficacy of five insecticides in controlling these three Oebalus species. These insecticides were applied at the maximum allowed a.i. (active ingredient) field rate in high volume (10 gal/A or 93.54 L/ha) to keep these two factors constant across the five insecticides. However, Florida rice growers question if a lower spray volume they typically employed affects