Evaluation of Biorational Products for Management of Phytophthora Blight of Bell Pepper Transplants

Abstract

There is a critical need for pest control products that are compatible with sustainable agricultural practices, such as those based on natural antagonists or plant defense activators. Four separate, repeated experiments were conducted in which commercially available biopesticides and phosphonate-containing products were evaluated in the greenhouse for the management of Phytophthora blight of bell pepper caused by Phytophthora capsici. The phosphonate-containing product, FNX-100, applied as a soil drench, was found to be the most effective treatment for decreasing the incidence of stem and crown rot. A single soil drench of FNX-100 applied at the lowest concentration provided disease control that was as effective as multiple applications of the highest rate. Foliar applications of FNX-100 at any concentration or frequency were ineffective for disease control, and caused pronounced phytotoxicity when compared to the FNX-100 soil drench. The phosphorous acid K-Phite was found to be less effective than FNX-100, but disease symptoms were minimal in plants treated with a soil drench of that product. While the efficacy of three other phosphonate-containing products, Prophyt, Phostrol, and FNX-2500, were inconsistent, it was observed that these products were also more effective in managing disease when applied as a soil drench rather than as a foliar spray. Accepted for publication 18 December 2012. Published 26 February 2013.