Prediction of optimal timing for chemical control of the nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera: Tortricidae), in the Southeastern coastal plain

Optimum spray dates for fenvalerate and dimethoate were determined for each of the four generations of Rhyacionia frustrana (Comstock) occurring in the Georgia coastal plain. As each insecticide was applied to different plots sequentially through a generation, damage by R. frustrana gradually decreased toward an optimum spray date, then increased. Optimum dates for fenvalerate application occurred 1 to 2.5 weeks earlier than for dimethoate. This difference was related to the phenology of the R. frustrana life cycle. A technique is presented whereby a grower can predict optimum spray dates by using pheromone-trap data and degree-day summations.