Control of Apple Scab in Commercial Orchards Through Primary Inoculum Management

Abstract

Apple scab, caused by Venturia inaequalis, is one of the most important diseases in applesin all production regions and its sustainable control is still a challenge. The aim of this work was tooptimize the control of apple scab through different environmentally friendly inoculum managementstrategies, specifically the removal of fallen leaves in winter and the treatment of ground leaves withthe biological agent Trichoderma asperellum (T34 BIOCONTROL®) to inhibit or prevent inoculumdevelopment in commercial orchards. The results obtained from 4 years of trials in commercialorchards demonstrated that the combination of fungicide treatments and leaf litter management,particularly through aspiration, significantly reduced the development of apple scab in comparisonwith strategies commonly used by growers that are based solely on fungicide application. Both theincidence and severity of the disease in leaves and fruit decreased by over 90% when inoculummanagement and fungicide treatments were combined. These results highlight that reducing thesource of inoculum by removing fallen leaves is an effective strategy that complements fungicideor biological control agent applications. In conclusion, combining eco-friendly strategies withstandard fungicides and monitoring environmental conditions can help to reduce the frequency ofphytosanitary applications, ultimately contributing to the goal of minimizing their use in the controlof apple scab.