Pheromone deployment strategies for mating disruption of a vineyard mealybug

Authors: DAANE, KENT - University Of California; COOPER, MONICA - University Of California - Cooperative Extension Service; MERCER, NATHAN - University Of California; Hogg, Brian; YOKOTA, GLENN - University Of California; HAVILAND, DAVID - University Of California - Cooperative Extension Service; WELTER, STEPHEN - San Diego State University; CAVE, FRANCES - University Of California; SIAL, ASHFAQ - University Of Georgia; BOYD, ELIZABETH - California State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2021
Publication Date: 10/20/2021
Citation: Daane, K.M., Cooper, M.L., Mercer, N.H., Hogg, B.N., Yokota, G.Y., Haviland, D.R., Welter, S.C., Cave, F., Sial, A.A., Boyd, E. 2021. Pheromone deployment strategies for mating disruption of a vineyard mealybug. Journal of Economic Entomology. 114(6):2439–2451. https://doi.org/10.1093/jee/toab198.
DOI: https://doi.org/10.1093/jee/toab198

Interpretive Summary: The vine mealybug (VMB) is a major pest of vineyards in California and other grape-growing regions throughout the world. It damages grape clusters and can weaken or kill vines in high numbers. Pesticides are often needed to control VMB, but are largely unavailable to organic growers and can kill natural enemies that would otherwise help to control VMB. Sustainable control methods for VMB are needed to meet increasing consumer demand for organically farmed products. One promising option is mating disruption, whereby vineyards are flooded with synthetic sex pheromone to disrupt mating in VMB and reduce VMB populations by preventing male VMB from finding females. Mating disruption is commercially available for Pl. ficus, but high costs have limited its adoption by growers. To improve the economic viability of mating disruption, three different technologies for deploying it were tested. Results showed that all three methods lowered mealybug numbers and grape damage. Dispensers that emit the pheromone passively were effective in lower numbers per acre than the rate that is commonly used. Male mealybugs flew mainly in the morning when temperatures were between 16 and 32°C, and it may be possible to program dispensers to emit pheromone only at these times. In a large field experiment mating disruption increased in effectiveness over three years of deployment. Results from all experiments suggest that the different deployment technologies can be used to help control VMB, even at reduced rates, especially if used over multiple years.

Technical Abstract: The mealybug, Planococcus ficus (Signoret), is a primary vineyard pest in California and other grape-growing regions throughout the World. Mating disruption programs are commercially available to manage Pl. ficus, but widespread adoption has been limited, in part, by high costs compared with insecticide programs. To improve mating disruption economic effectiveness, different deployment technologies (passive, aerosol, and microencapsulated formulations) were individually examined. Adult male Pl. ficus captures in pheromone traps and categorical ratings of vine infestation or crop damage suggest that all deployment strategies lowered mealybug densities or damage. Using passive dispensers, deployment rates of 310 and 465 per ha lowered Pl. ficus crop damage similar to 615 per ha, a rate commonly used in commercial operations; reduced rates would lower product and deployment costs. Meso dispensers, containing more a.i., deployed at 35 per ha did not have a treatment impact, but a microencapsulated formulation and aerosol canisters lowered male flight captures and/or crop damage. Male mealybug flight activity was greatest from 0500-1100 h, which coincided with temperatures >16°and <32°C. These restricted times and temperatures suggests a programable dispensers might allow pheromone deployment to coincide only with flight patterns. A large field trial using passive dispensers found greater treatment separation after 3 yrs of pheromone deployment. Discrepancies in results among vineyard may be related to Pl. ficus density, but combined results from all trials suggest that different deployment technologies can be used to impact Pl. ficus densities and damage, even at reduced rates, especially with continued use over multiple seasons.