Field Efficacy of Hand-Applied Mating Disruption for San Jose Scale in Sweet Cherries

Project goal: To investigate new San Jose scale mating disruption techniques to improve management efficacy in sweet cherry.

Project description:  We collaborated with growers in five sweet cherry orchards in northwest Michigan with known infestations of San Jose scale.  Field plots, from one to two acres in size, were established at each orchard site; each orchard had one plot treated with SJS mating disruption and one untreated plot. Each orchard had a buffer at least equal size or larger than the experimental plots that separated the treated and untreated plots. The SJS pheromone dispensers impregnated with Isomate SJS provided by Shin-Etsu Chemical Co. were deployed in May at all orchard sites at a rate of two dispensers per tree. One dispenser was place on either side of the tree in the orchard row middle. All of the experimental orchards were commercially managed for pests and diseases as needed by the growers; some orchards also included dormant and/or in-season insecticide applications for SJS.

To determine the effectiveness of the Isomate SJS dispensers, we measured and compared the population density of male SJS in the treated and untreated plots using Trécé Pherocon V San Jose Scale pheromone-baited traps. Four traps in a square-grid orientation were placed in each experimental plot for a total of eight traps per orchard site. Traps were replaced and counted weekly during the first and second flights of male SJS.  We also measured crawler density for the first and second crawler emergences using black electrical tape wrapped around tree branches. After 24 hours, the tape was collected and brought back to the lab where we used a dissecting microscope to identify and count the crawlers.

Results: SJS mating disruption 2020

Project lead/collaborators: Emily Pochubay, Larry Gut, and Nikki Rothwell

Funding sources:  Michigan Cherry Committee and Project GREEEN

Start year: 2019

End year: 2020