Effect of Imidacloprid and Acephate for Tobacco Thrips (Thysonaptera: Thripidae) Management on Flumioxazin Injured Peanut

Experiments were conducted in 2016 and 2017 in Stoneville, MS and Starkville, MS to determine the impact of different insecticide management options for thrips on herbicide injured peanut. Insecticide treatments included imidacloprid in-furrow at-planting, one or two foliar applications of acephate, and an untreated control with and without an application of flumioxazin. In Stoneville, herbicide applications were made immediately following planting, and in Starkville, applications were made as plants were emerging to maximize herbicide injury. The Stoneville experiment also had an additional factor in which plots were flooded or not flooded to simulate a heavy rainfall in order to maximize herbicide injury and also to give added stress from saturated soils. Thrips counts, thrips injury ratings, plant vigor ratings, plant biomass, width between plant canopies, and yield were recorded.  Few interactions were observed, but temporary flooding, herbicide injury, and thrips injury affected peanut growth as measured by biomass and canopy.  Imidacloprid was the most consistent insecticide treatment for reducing thrips numbers and injury, but acephate provided some protection.  Temporary flooding during the seedling stage, flumioxazin injury, and thrips injury all reduced peanut pod yield.  Based on these results, every attempt should be made to minimize early season stress in peanuts including the use of an effective in-furrow insecticide.