Sparganothis fruitworm has two generations a year and overwinters as an early-instar larva. Larvae from the 1st generation feed on foliage (Picture 1). In New Jersey, first generation adult moths (Picture 2) emerge from mid-June through the first weeks in July; pheromone traps are commonly used to monitor adult flight and population size. Second-generation eggs are laid on cranberry leaves, and larvae will feed on fruit.
This insect is typically controlled by their natural enemies and overuse of insecticides pre-bloom, particularly those of broad-spectrum activity, can disrupt biological control. Thus, we normally do not recommend treatment before bloom. If populations exceed threshold levels then growers can use reduced-risk insecticides such as Intrepid, Altacor, and Delegate to manage this insect. The timing for post-pollination sprays is at two weeks after peak pheromone trap catches.