Areawide mating disruption for control of vine mealybug (Planococcus ficus) in Napa vineyards

In cooperation with 29 Napa County growers, we tested areawide mating disruption for control of vine mealybug, Planococcus ficus. Plastic pheromone dispensers were deployed from 2011-2012 throughout three treatment areas totaling over 430 acres. To monitor adult male vine mealybug flights, pheromone traps were placed throughout the treatment areas from June to December in each year. To assess changes in mealybug populations after removal of the pheromone, pheromone traps were deployed again in fall 2013 (to coincide with peaks in mealybug numbers) throughout the former treatment areas in the same locations as previous years. Results showed no increase (spread) of vine mealybug from 2011 to 2012, and male mealybug numbers in the majority of traps in “hotspots” with measurable mealybug populations showed decreases from 2011 to 2012. After the removal of the pheromone dispensers in 2013, numbers of vine mealybugs in pheromone traps increased dramatically in two out of three of the former mating disruption areas. There was also evidence that vine mealybug populations were spreading at these two sites.