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The goal of this project is to better understand development of antimicrobial resistance (AMR) and how we can maintain effective tools in disease management in an integrated manner using a whole systems approach with biological control and horticultural practices. Altogether, this will contribute to effective and sustainable disease management for years to come.Objective 1:Determine the effect of fungicide application dose on resistance development and establishment within an apple orchard: This objective aims to see the cumulative effect of continuous fungicide application using either a high or a low dose of the SDHI fungicide, fluxapyroxad, on fungicide resistance development in the apple scab pathogen,Venturia inaequalis.To evaluate this in a field setting, a. fungicide applications are made each season, b. isolates are collected from the field, c. samples are isolated from leaves, d. fungicide sensitivity assays are completed, and f. data is analyzed. For a second approach as a backup to address the same objective in case results are inconclusive, we will conduct a similar study in a controlled lab environment using repeated application of the SDHI fungicide, benzovindiflupyr on the causal agent of grey mold, Botrytis cinerea, inoculated on detached grapes. This experiment will follow similarsteps as above.Objective 2:Develop an integrated management program using contemporary horticultural practices,disease forecasting, and biopesticides as an alternative to environmentally unsafe broad-spectrum fungicides: This objective aims to combine the super spindle planting architecture, disease forecasting, and the highly effective SDHI fungicides to develop a management plan where biological controls could be used to replace broad spectrum fungicides like captan and mancozeb which have potentialoff-target effects.We hypothesized that by taking advantage of smaller tree canopies, we can effectively replace broad spectrum fungicides with biopesticides, while using single-site SDHI fungicides during critical infection periods as predicted by forecasting models.To evaluate this in a field setting, a. fungicide applications need to be made each season, b. disease ratings will be performed, c. isolates are collected and processed, d. fungicide sensitivity testing is completed, and e. data is analyzed.Objective 3:Disseminate research results to growers to develop innovative fungicide management programs to address challenges of antimicrobial resistance development and new production paradigms.Through understanding practices that decrease selection for AMR as well as decrease reliance on broad-spectrum fungicides, growers can more sustainably manage fungal diseases. Dissemination and incorporation of these research outcomes into growers' management programs will help ensure sustainable production of apple with off target effect. This will be done through presentation to growers at both formal and informal meetings.