The electrophoretic patterns of total soluble proteins and eight isozymes (alkaline phosphatase, esterase, fumarase, NAD-glucose dehydrogenase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase and superoxide dismutase) of the isolates from avocado were identical to the patterns of two P.
The identification was confirmed by the electrophoresis of mycelial proteins on polyacrylamide slab gel. The isolates were identified primarly on the basis of morphological and cultural characters. cinnamomi was isolated on BNPRAH selective medium from feeder roots and rhizosphere soil of both symptomatic and asymptomatic trees, as well as from trunk bark of trees showing symptoms of collar rot. Infected trees were of various commercial cultivars, including Anaheim, Bacon, Colin, Fuerte, Hass, Nabal, Nowels, Orotawa, Pinkerton, Reed, Regina, Rincon and Zutano, and were grafted on two rootstocks, G6 and Hass seedlings. Symptoms on the canopy were always associated with root rot and, only in few cases, with collar rot as well. Trees with symptoms of decline, including wilting, chlorosis and leaf drop, dieback of twigs and branches and eventually collapse of the whole tree, were observed in an experimental field near Rocca di Caprileone (province of Messina) in the Tirrenic coast of Sicily. Root rot caused by Phytophthora cinnamomi Rands is reported for the first time in Italy. All the isolates from avocado were A2 mating type cinnamomi strains used as reference, isolate IMI 70473 from International Mycological Institute (UK) and an isolate from myrtle originating from Sardinia.