Refining spray strategies to optimize sustainable pest and disease management in cherry orchards

Project goal: We will determine if alternate row middle (ARM) applications provide effective and sustainable management of tart cherry pests and diseases at different times during the season as well for different age/size tree canopies. This research will help us further tailor management recommendations that account for seasonality, orchard age, and/or canopy size, and these parameters have the potential to reduce operator fatigue and optimize seasonal pest and disease control.

Project description:  We compared seasonal spray coverage of ARM vs. full cover applications in 8-yr old and 15-yr old Montmorency tart cherry blocks at the NWMHRC.  In blocks of both tree ages, four replications of three spray strategy treatments were evaluated for spray coverage: 1) season-long ARM sprays, 2) season-long full cover sprays, and 3) early-season ARM sprays followed by midseason to pre-harvest full cover sprays.  Spray cards (1” x 1”) were secured into tree canopies in five zones in each treatment.  Blue food grade dye was added to the airblast sprayer to ‘trace’ coverage.  Three spray timings were assessed: post-bloom, straw-color, and pre-harvest.  Spray cards were collected and measured for percent coverage with ImageJ software.  Pest and disease efficacy was also measured in ARM vs. full coverage applications. In treatments using ARM sprays, applications were made every 4-5 days; full cover applications were made every 7-10 days depending on timing in the season. Spray programs were developed based on the most recent pest and disease efficacy data. Early season spray programs targeted the typical pest and disease complex such as brown rot, cherry leaf spot, powdery mildew, green fruit worm, obliquebanded leafroller, and plum curculio at appropriate timings. Spotted wing drosophila management began during the third week of June or when fruit are just losing their green color and are susceptibile to SWD egg laying. Program efficacy was evaluated for each treatment by measuring cherry leaf spot and powdery mildew incidence at two timings. We collected and processed fruit using the brown sugar extraction method to measure the level of SWD infestation among the spray programs.

Results: Refining spray strategies to optimize pest management 2018

Project lead/collaborators: Emily Pochubay and Nikki Rothwell

Funding sources:  Michigan Cherry Committee

Start year: 2018

End year: 2018