Thrips Injury Can Reduce Peanut Yield and Quality under Conditions of multiple Stress

Severe injury from tobacco thrips [Frankliniella fusca (Hinds)] to seedling peanut (Arachis hypogaea L.) has not been documented to reduce yield and quality. However, thrips injury may be economically important when combined with another factor, such as postemergence herbicide injury. This note reports results of a field experiment in which control of tobacco thrips during an unusually dry early season greatly increased peanut seed yield and quality. ‘Florunner’ peanut was grown using preplant and postemergence herbicides for weed control. Treatments consisted of an untreated control and four labeled insecticides applied at planting or soon after crop emergence. Populations of adult tobacco thrips were significantly suppressed by aldicarb [2‐methyl‐2‐(methylthio) propionaldehyde O‐(methylcarbamoyl) oxime]; all insecticides significantly suppressed immature thrips. Aldicarb, the most efficacious insecticide treatment, significantly improved peanut yield by 32% and quality as determined by percentage of total sound mature kernels. All but one of the remaining insecticide treatments significantly improved seed yield, with increases ranging from 9 to 31%. Rainfall was extremely low early in the growing season, and (based on 41 yr of records at the site) drier conditions occur 10% of the time. This is a frequency great enough to matter, but low enough to make further research difficult. The observations reported here suggest that early‐season moisture stress intensifies peanut yield and quality losses associated with combined injury from thrips and postemcrgence herbicides.