Mechanisms mediating false codling moth, Thaumatotibia leucotreta (lepidoptera: Tortricidae), mating disruption using...

False codling moth (FCM) is a polyphagous Tortricid moth that is a priority agricultural pest. Mating disruption shows potential as an environmentally friendly and sustainable control option against FCM in stone fruit, table grapes and citrus. How the technique alters the mate-finding ability of FCM and what factors are important to ensure the control success is uncertain. Recent work indicated that Lepidoptera are disrupted either competitively or non-competitively. No studies have yet been conducted on FCM to determine its disruptive mechanism. However, studies conducted on closely related species have proposed and critically evaluated a framework, along with a dichotomous key, for distinguishing between the two mechanisms.

A protocol for identifying the underlying disruption mechanism in other species is provided. Here the dosage-response profile, the optimal dosage and optimal density were calculated from multiple mark-release-recapture (MRR) experiments, using sterile FCM. Stone fruit and table grape blocks were treated with increasing levels of pheromone dispenser densities, which allowed the level of disruption experienced (FCM caught in treated/untreated blocks) to be calculated. While mating disruption proved highly effective in stone fruit and table grapes against FCM, the FCM followed a hybrid disruption profile and were disrupted competitively at low dosages and non-competitively at higher dosages.

The shift to non-competitive disruption, which resulted in 99% disruption, was achieved at a dosage of 800 dispensers/ha uniformly distributed and remained effective with as few as 36 pheromone release sites per ha. Mating disruption is, therefore, highly recommended to form part of the current integrated pest management program for FCM. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.