DETECTION OF PHYTOPHTHORA-CAPSICI IN PEPPER AND CUCURBIT CROPS IN OHIO WITH 2 COMMERCIAL IMMUNOASSAY KITS

Phytophthora capsici was shown to be the principal species associated with Phytophthora blight of peppers and cucurbits in Ohio during 1992 and 1993. Both A1 (31.5%) and A2 (64.2%) compatibility types were foun d in peppers, and only A2 isolates were obtained from cucurbits. Phyto phthora cactorum was recovered from two cucurbit samples. The Alert Ph ytophthora ''flow-through'' immunoassay and the Agri-Screen multiwell ELISA kit E for Phytophthora were compared for their efficacy. The for mer detected P. capsici in pepper and cucurbit crops, and had the adva ntage of being rapid (10 min) and easy to perform. The latter was effe ctive in detecting P. capsici in pepper tissue, but absorbance values for healthy cucurbit tissues were relatively high. Agreement between E LISA and isolation of P. capsici or P. cactorum on semiselective mediu m was excellent for both kits. Phytophthora antigen was detected in th ree of seven field soils using the ELISA kit E combined with a soil or ganic matter extraction-concentration protocol.