Pheromone-Mediated Mating Disruption as Management Option for Cydia spp. in Chestnut Orchard

SIMPLE SUMMARY: Investigations were conducted to evaluate the effectiveness of mating disruption (MD) to control chestnut tortrix moths. Surveys were performed at four sites in northern Italy in 2019–2020. MD was carried out using the pheromone dispenser Ecodian(®) CT. The total number of trapped males was significantly lower in MD plots than in control ones for all sites and years. Trap catch suppression in MD plots averaged 89.5% and 93.8% for Cydia fagiglandana and 57.4% and 81% for Cydia splendana in 2019 and 2020, respectively. A reduction of about 71% of larval infestation of chestnut fruits was only recorded in the MD plot at one site in 2019. Although the reduction in male catches in MD plots was observed, this research highlighted the need to perform further studies to investigate the effect of MD in reducing larval damage of chestnut fruits. ABSTRACT: (1) Background: Pheromone-based devices are successfully used to control insect pests in agriculture. (2) Methods: Investigations were conducted to evaluate the effectiveness of mating disruption (MD) to control the chestnut tortrix moths, Cydia fagiglandana and Cydia splendana. Surveys were performed in northern Italy in 2019–2020. MD was carried out using the pheromone dispenser Ecodian(®) CT. The effectiveness of MD was assessed by recording male adult catches in pheromone-baited sticky traps and larvae in chestnut fruits, comparing MD and control plots. (3) Results: The total number of trapped males was significantly lower in MD plots than in control ones, for all sites and years. Trap catch suppression in MD plots averaged 89.5% and 93.8% for C. fagiglandana and 57.4% and 81% for C. splendana in 2019 and 2020, respectively. The larval infestation rate in fruits did not vary between plots except for one site where a reduction of about 71% in the MD plot was recorded in 2019. (4) Conclusions: Low catches in MD plots turned out to be a good measure of the effectiveness of communication disruption, but no satisfactory data have been obtained regarding fruit infestation, highlighting how the reduction of male catches cannot always be considered as a reliable indicator of successful control. Specific investigations about background population density, dispersal and mating/oviposition behavior are thus essential for a viable management strategy.