Reduced-risk insecticide programs for managing direct pests in apple orchards: Efficacy and limitations

Direct apple pests, including codling moth (Cydia pomonella) and plum curculio (Conotrachelus nenuphar), cause significant economic losses in apple orchards worldwide. With the phase-out of broad-spectrum insecticides, evaluating reduced-risk alternatives has become crucial for sustainable orchard management.

This study aimed to evaluate the efficacy of insecticide programs based on modern reduced-risk chemistries against key direct apple pests, with a particular focus on the experimental insecticide cyantraniliprole.

A replicated field trial was conducted in Urbana, Illinois, USA, during the 2013 growing season. Five insecticide programs plus an untreated control were compared using a randomized complete block design. Fruit damage assessments were conducted mid-season and at harvest.

All insecticide treatments significantly reduced (p < 0.05) internal Lepidoptera damage (codling moth and oriental fruit moth) at harvest compared with the untreated control. Cyantraniliprole, indoxacarb, and chlorantraniliprole-based programs provided excellent control with near-zero infestation levels. However, none of the insecticide programs provided significant control of plum curculio oviposition scars at harvest, highlighting a critical limitation in current management strategies that remains a challenge today.

Reduced-risk insecticides, such as cyantraniliprole, represent valuable tools in IPM programs against Lepidopteran pests. However, the consistently limited efficacy of chemical means to control plum curculio underscores the necessity of integrating non-chemical control tactics for sustainable management of this key pest. This study, conducted in 2013, provides a foundational assessment that contemporary IPM must integrate newer chemistries and non-chemical strategies to address potential resistance and evolving pest pressures.