Suppressive effect of two fungicides against hydrangea bacterial spots during seedling management in fields

Abstract

In this study, we investigated the suppressive effect of polycarbamate and organic copper against hydrangea bacterial spots associated with Acidovorax valerianellae. The application of polycarbamate significantly suppressed the disease in four of five trials, while organic copper significantly suppressed the disease in two of three trials. We used generalized liner mixed models to evaluate the integrated effect of each of the two fungicides throughout all trials. In our experimental model, the coefficients of polycarbamate and organic copper application in reference to the negative control were −0.70 and −0.90, respectively (p < 0.01). These results indicate that the application of these fungicides can effectively suppress hydrangea bacterial spots. To best of our knowledge, this is the first report that fungicides can suppress disease related to A. valerianellae and will contribute to disease prevention during hydrangea production.