A Method to Monitor the Activity of Phytophthora spp. in the Root Zone of Pistacia spp.

Abstract

A method was developed to monitor the formation of zoospores of Phytophthora species in the soil around potted host plants grown under greenhouse conditions. Inoculum of the pathogen was grown in vermiculite amended with hemp seed extract for 4 weeks at room temperature and 10 ml was placed around each plant. Pots were periodically flooded with water overnight with the drainage hole closed. Water was drained and collected next day and baited with citrus leaf discs for 48 h at room temperature and plated on a Phytophthora selective antibiotic medium. Baits colonized with Phytophthora were good indicators of the pathogen activity in the root zone of susceptible and resistant hosts.