Whether it’s navel orangeworm in nuts or vine mealybug in vines, unmanaged late flights can lead to significant numbers of overwintering pests and increase damage levels next season. The first and most important IPM activity for growers of nut crops is winter sanitation, but additional IPM tools like sprayable pheromones can be combined with essential sanitation practices to further reduce overwintering pest populations and provide the cleanest slate possible to protect next year’s crop. There are two options to continue pheromone mating disruption for post-harvest pest management:
Apply Sprayable Pheromone Mating Disruption Post-Harvest
Many PCAs are already planning post-harvest foliar applications of nutrients in tree nuts and grapes. If growers choose to make those applications, it allows for a “free ride” of sprayable pheromone products to be included in the tank.
Every orchard is unique with its own native and transient pressure of moths plus the mummy load. The sprayable products allow you to take a proactive approach, particularly on problematic blocks. This is a good choice for growers who did not use season-long mating disruption.
Leave Season-Long Pheromone Dispensers Up All Winter
Many growers faced higher pest pressure in 2021. Late season pest populations are often the most abundant because their numbers have increased exponentially each generation throughout the season, making it especially important to leave season-long aerosol emitters or hanging dispensers up as long as possible post-harvest. In many cases, there will be plenty of active ingredient in the product to emit pheromone through at least October, depending on the type of product and when it was deployed. Leaving the products in the orchard or vineyard into the fall or over winter will provide more protection than removing the products at harvest.
In the case of aerosol emitters, this practice may also save growers money on labor because growers can remove the previous season’s product in the spring at the same time they are hanging the product for 2022.
Whether you choose a free-ride of pheromone mating disruption spray in your post-harvest nutrient program or merely encourage your growers to leave season-long emitters up all winter long, pheromones can reduce with overwintering pest pressure and help with a clean start to 2022.
contributed by Mike Portugal, Suterra PCA