Submitted to: Fungicide and Nematocide Tests
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2005
Publication Date: 4/1/2005
Citation: Turechek, W., Heidenreich, M.C. 2005. Evaluation of fungicides for control of botrytis and anthracnose fruit rots on strawberry, 2004. Fungicide and Nematocide Tests. 60:SMF021. Interpretive Summary: Gray mold and anthracnose are the two most important fungal diseases in commercial strawberry production. Growers rely on fungicides to control these two diseases to produce marketable fruit. We tested seven organically acceptable fungicides and two recently labeled conventional fungicides against the industry standard for their ability to control the two diseases. We found that the two conventional fungicides provided excellent control of anthracnose, as well as the industry standard, but the seven organically acceptable fungicides failed to provide commercially acceptable control. Gray mold did not develop in these trials, therefore evaluation was not possible. The results indicate that growers can expand their tools for managing disease, which is important in the context of managing fungicide resistance, but emphasizes the need for further research to develop disease management alternatives suitable for the organic market.
Technical Abstract: Gray mold (Botrytis cinerea) and anthracnose (Colletotrichum acutatum) of strawberry are the two most important fungal diseases in commercial strawberry production. Nearly every fungicide application applied during the growing season targets at least one of these two diseases. However, the public perception of fungicides in commercial agriculture is, by and large, negative. Growers recognize this and generally strive to minimize their fungicide usage and/or select non-toxic, environmentally friendly fungicides that provide commercially acceptable control. To assist growers with their selection of fungicides, a field trial was designed to evaluate the efficacies of several biorational fungicides against gray mold and anthracnose, and compare their performance to those most widely used in commercial production. The results showed that all treatments that included the industry standard fungicides Captan, CaptEvate, or Pristine provided excellent control of anthracnose. Switch fungicide, primarily used to control gray mold, provided reasonably good control of anthracnose. The biorational fungicide treatments Citrex (a citrus extract), Elexa 4 PDB (a so-called 'plant defense booster'), Kaligreen (potassium bicarbonate), Kumulus (sulfur), Messenger (a harpin protein), Oxidate (hydrogen dioxide) and Serenade (Bacillus subtilis) provided little to no control of anthracnose. Elevate fungicide, an industry standard for managing gray mold, is not labeled for control of anthracnose, provided no control of the disease. Gray mold did not develop in these trials, therefore evaluation was not possible. The results indicate that growers can expand their tools for managing disease, which is important in the context of managing fungicide resistance, but emphasizes the need for further research to develop disease management alternatives suitable for the organic market.