Evaluation of spray programs containing famoxadone plus cymoxanil, acibenzolar-S-methyl, and Bacillus subtilis compared to copper sprays for management of bacterial spot on tomato

摘要

Bacterial spot caused by Xanthomonas euvesicatoria Jones et al. and Xanthomonas perforans Jones et al. is a major disease on fresh market commercial tomato in Florida. Fourteen field trials were conducted between 1999 and 2005 (10 in south Florida and four in north Florida) testing famoxadone plus cymoxanil (Tanos 50DF (R), E.I. du Pont de Nemours and Company, Wilmington, DE), Bacillus subtilis strain QST 713 (B. subtilis) (Serenade WPO (R) or Serenade Max (R), AgraQuest, Inc., Davis, CA), and acibenzolar-S-methyl (ASM) (Actigard 50WG (R). Syngenta Crop Protection, Greensboro, NC) at different rates and in various application programs that were combined and rotated with copper hydroxide and mancozeb for management of bacterial spot. In field applied spray treatments containing famoxadone as a component, all of the programs significantly reduced bacterial spot severity on plants compared to the untreated control plants (UTC) and 97% of the programs were equal for disease suppression conferred by the copper-mancozeb standard. In spray programs containing ASM or B. subtilis plus copper hydroxide, treated plants had significantly reduced disease compared to the UTC plants and were not different from the plants treated with the copper-mancozeb standard. Yield data from small plots was unaffected. Several of the programs which used these compounds in rotation with copper-mancozeb provided similar levels of reduction in the disease severity for bacterial spot while reducing by 50% the amount of copper applied to plants. The effect of famoxadone plus cymoxanil on the survival of Xanthomonas in vitro did not cause a significant reduction in the bacterial population and was not determined to be directly bactericidal. However, greenhouse and field testing supports disease reduction of bacterial spot on plants treated with these compounds. The products tested in these trials may be useful, alternative tools for use in an integrated management program for bacterial spot on tomato.