Enhancing hazelnut protection: Low-rate pheromone dispensers for filbertworm mating disruption

Hazelnut is an economically important crop that provides significant income to growers in Oregon, USA. Filbert worm (FBW), Cydia latiferreana, is one of the economically crucial pests in hazelnut production resulting in injured and unmarketable nuts. Hatched larvae burrow inside the nut and feed throughout the season. Several insecticides are in use to control damaging FBW populations.  Insecticide use may cause secondary pest resurgence and reduce the biological agent populations in the orchard. Mating disruption is a method to minimize insecticide use while reducing pest damage. In the present study, low rate of ISOMATE HSW Flex pheromone dispensers were deployed to evaluate the efficacy of FBW mating disruption in hazelnut orchards. Experiments were conducted in eight hazelnut orchards. ISOMATE HSW Flex dispensers were evenly deployed in the field with application rates of 0, 10, 20, 20C, 30, 50, and 100/ acre in 2021 and 0, 5, 10, 15, 30/ acre in 2022 and 2023. In addition, 0.5 and 1 m ring dispensers were used as a standard mating disruption application. Dispensers were applied to the upper 1/3 of the canopy approximately 3-4 m above the ground level. Male FBW counts were checked weekly by placing two pheromone-baited delta traps in treated each plot. The results indicate that low-rate dispensers disrupt equally compared to standard mating disruption application. Additional research is necessary to better understand low-rate treatments in a large-scale field scenario and determine their costs and benefits.