Areawide mating disruption for vine mealybug in California vineyards

Authors: Hogg, Brian; COOPER, MONICA - University Of California - Cooperative Extension Service; DAANE, KENT - University Of California

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2021
Publication Date: 6/9/2021
Citation: Hogg, B.N., Cooper, M.L., Daane, K.M. 2021. Areawide mating disruption for vine mealybug in California vineyards. Crop Protection. 148: Article 105735. https://doi.org/10.1016/j.cropro.2021.105735.
DOI: https://doi.org/10.1016/j.cropro.2021.105735

Interpretive Summary: The vine mealybug (VMB) is an invasive pest of vineyards that feeds on grape clusters and can transmit plant viruses. Pesticides are currently the most effective means for controlling VMB. However, conventional pesticides are not available to organic growers, and sustainable control methods for VMB are needed to meet increasing consumer demand for organically farmed products. One promising, environmentally sustainable option is mating disruption, whereby vineyards are inundated with synthetic sex pheromone to disrupt mating in VMB and reduce VMB populations by preventing male VMB from finding females. Here we report on a three-year study of VMB mating disruption in Napa County, California, where pheromone dispensers were deployed across large sites. Sites were also sampled that did not receive pheromone. Numbers of male VMB in pheromone traps reflected mealybug numbers on vines and grape damage, and helped to pinpoint VMB ‘hotspots’ to be treated with pesticides. Numbers of VMB at mating disruption sites were far lower than untreated sites, although mealybugs were still present at mating disruption sites. Mating disruption appeared to limit VMB numbers and spread, particularly in areas where numbers of VMB were low initially. In the third year areawide mating disruption was discontinued, and numbers of VMB increased at most of the former mating disruption sites. These results suggest that mating disruption and well-timed, effective insecticides play complementary roles, and that monitoring the distribution of pests across large areas is critical for effective pest control.

Technical Abstract: Vine mealybug, Planococcus ficus (Signoret), is one of the more damaging vineyard pests and an important vector of Grapevine leafroll-associated viruses. Mating disruption is a promising and environmentally sustainable control tool for Pl. ficus. Here we report on a three-year areawide study of Pl. ficus mating disruption in Napa County, California, where pheromone dispensers were deployed across large (53-66 ha), multi-owner sites that were paired with sites that did not receive pheromone. Male Pl. ficus captures in pheromone traps were correlated with mealybug numbers and crop damage, and were useful in identifying ‘hotspots’ to be targeted with insecticide applications for areawide control. Trap catches at mating disruption sites were far lower than untreated sites, although mealybugs were still present at mating disruption sites. Evidence indicated that mating disruption limited Pl. ficus density and spread, particularly in areas with low initial mealybug densities. In the third year, areawide mating disruption was discontinued at the former mating disruption sites and, as evidence of its impact, Pl. ficus trap captures increased. These results suggest that mating disruption and well-timed, effective insecticides play complementary roles, and that monitoring the areawide distribution of pests is a critical component of pest control programs.