Effectiveness of Nine Different Fungicides for Management of Crown and Root Rot of Chile Pepper Plants Caused by Phytophthora capsici

Matheron, M. E., and Porchas, M. 2015. Effectiveness of nine different fungicides for management of crown and root rot of chile pepper plants caused by Phytophthora capsici. Plant Health Progress doi:10.1094/PHP-RS-15-0028. Bell and chile pepper plants are affected by the economically important disease Phytophthora blight, which is caused by the oomycete pathogen Phytophthora capsici. Greenhouse and field trials were conducted to evaluate and compare the ability of nine different fungicides to reduce development of the crown and root rot phase of Phytophthora blight and the resulting chile pepper plant death when applied at 2and 4-week intervals. Overall, chile pepper plant mortality was significantly decreased in three greenhouse trials with soil applications of fungicide products containing ametoctradin + dimethomorph, cyazofamid, dimethomorph, ethaboxam, fluazinam, fluopicolide, mandipropamid, mefenoxam, and oxathiapiprolin. The same fungicides, excluding mandipropamid and oxathiapiprolin, also significantly reduced overall plant mortality in two field trials. No significant difference was found between 2and 4-week fungicide application intervals with respect to chile pepper plant survival in any greenhouse or field trial. In general, the degree of reduction in chile pepper plant mortality was lower in field compared to greenhouse trials, probably due to the respective soil surface spray compared to soil drench method of fungicide application used in each instance.