Who should go first–Altacor or Delegate?

Two new insecticides have recently been registered for codling moth (CM) control in pears; they are Altacor (chlorantraniliprole) by DuPont and Delegate (spinetoram) by Dow AgroSciences. The Delegates label states “Avoid use of the same active ingredient or mode of action (Group 5) on consecutive generations of insects. However, multiple applications to reduce a single generation are acceptable.” The Altacor label states, “These (resistance management) strategies may include incorporation of cultural and biological control practices, alternative mode-of-action classes (group 28) of insecticides on succeeding generations and targeting the most susceptible life stage.” Thus, there has been a debate on which product should be applied for the first generation CM control and which should be applied for the second generation. To address this question, field longevity and toxicity of these two products were evaluated and alternating control strategies, i.e. two applications of Altcor was applied for first generation and two applications of Delegate was applied for the second generation and the reverse were evaluated for CM and secondary pests on pears in California. The results of these studies will be presented and recommendations and justifications for these recommendations will be discussed.