POSTERS: Chemical control
Efficacy and baseline of succinate dehydrogenase inhibitor (SDHI) fungicides for management of Colletotrichum crown rot of strawberries
Michelle Oliveira - Gulf Coast Research and Education Center, University of Florida. Natalia Peres- University of Florida - Gulf Coast Research and Education Center, Leandro Cordova- Gulf Coast Research and Education Center, University of Florida
The current management of Colletotrichum crown rot (CCR) of strawberry, caused by Colletotrichum gloeosporioides, relies on the use of a few fungicide classes. Since resistance to QoI fungicides was recently detected, alternative fungicide groups are needed to control the disease. Our objective was to evaluate the efficacy of succinate dehydrogenase inhibitor (SDHI) fungicides in managing CCR. Twenty-plant plots of cultivar Strawberry Festival were inoculated 4 weeks after planting. Five SDHI fungicides, fluopyram, isofetamid, penthiopyrad, fluxapyroxad, and benzovindiflupyr, were either applied 2 days before or one day after inoculation (DAI). SDHI treatments were compared with a non-treated control and with the most common fungicides used on CCR management, i.e. thiophanate-methyl, pyraclostrobin, and captan. CCR incidence was evaluated once a week by counting the number of wilted and dead plants. Benzovindiflupyr applied 1 DAI was effective in reducing plant mortality and disease development. Captan was the most effective when applied preventively. The baseline of 100 C. gloeosporioides isolates was determined in vitro using a spiral gradient dilution assay. The EC50 for benzovindiflypyr and penthiopyrad varied from 0.08-1.11 and 0.45-3.17 µg/mL, respectively, whereas the other SDHI fungicides did not inhibit fungal growth. Our results indicate that benzovindiflupyr could serve as an alternative to manage CCR in Florida if the product is registered.