Simple Summary
Codling moth (CM) is a worldwide pest of apples and pears, feeding directly on the fruit. Growers have widely adopted the use of mating disruption (MD) with various formulations to help manage CM, but surprisingly have not carefully assessed the mating status of wild females. A new dual-sex non-pheromone lure was recently used in 2021–2022 to ascertain the level of female mating across 142 pome fruit orchards. The proportion of females mated varied widely among MD-treated orchards, with the median proportion of unmated females being <0.50, only ~0.20 higher than in untreated orchards. Following this initial study, 20 different MD programs were assessed in 82 orchards during 2023–2024, including programs using more than one MD-based tactic. Mark–recapture of sterilized moths was used to minimize orchard variability due to CM immigration. The most effective programs had >75% and >90% unmated wild and sterilized females, respectively. These more effective MD programs may be useful for organic orchards of premium cultivars with concerns for effective CM management.
Abstract
Implementing mating disruption (MD) programs to manage codling moth (CM), Cydia pomonella (L.), should be based on knowledge of how effectively each program disrupts female mating. A recent survey of 142 pome fruit orchards under MD in Washington State and Oregon found that, on average, about half of the CM females caught in traps baited with a kairomone-based lure were mated. However, significantly lower proportions of mated females were sampled when the intensity of the MD program was increased. A standardized protocol that could reduce the large inter-orchard variability was developed, involving weekly releases of sterilized CM adults. Eleven trials were conducted in 2023 and 2024 across 82 orchards treated with 20 MD programs. The intensive MD programs were significantly more effective in reducing mating of both wild and sterile CM females. Three advantages of using sterile moths to assess CM MD were identified: (i) it minimized the impact of wild immigrant females or individuals previously exposed to sublethal spray residues; (ii) it allowed greater numbers of females to be dissected, thus increasing the precision of the mean value; and (iii) it and allowed the collection of sufficient sampling data (>5 CM females per site) from 30% more orchards than relying on wild moth catch.