SUSCEPTIBILITY OF LOW CHILL PEACH ROOTSTOCKS TO PHYTOPHTHORA SPP

Peach seedlings (Prunus persica L. Batsch cv. Ansbacher, Boyles, Clark e's Shanghai, Neilson (Fred Hill), Okinawa, O'Meara, Richens Nos 1, 2 and 3, Tomm's Early and Tomm's Shanghai), which are commonly used as r ootstocks for low chill peaches in coastal New South Wales, were all s usceptible to Phytophthora cinnamomi and P. cambivora and to a lesser extent P. parasitica, P. citricola, P. cryptogea, and P. megasperma, w hen tested by stem inoculations in the glasshouse. Myrobalan H29C plum (P. cerasifera Ehrh.) cuttings showed more resistance than peach seed lings. Variety of seedling peach was highly significant in stem inocul ation experiments, but the performance of each varied between experime nts. Root inoculations in aerated nutrient solution showed all rootsto cks were susceptible to P. cinnamomi, but Neilson (Fred Hill) peach wa s more tolerant than other seedling peaches and less tolerant than Myr obalan H29C plum. No recommendation could be made on a rootstock for l ow chill peaches more tolerant of root and collar rots and waterloggin g.