%0 Journal Article %T Variability in Pathogenicity among Tunisian Isolates of Phytophthora cactorum as Measured by Their Ability to Cause Crown Rot on Four Apple Cultivars and MM106 Roostock %A N. Boughalleb %A A. Moulahi %A M. El Mahjoub %J Journal of Agronomy %D 2006 %I %X Studies on two isolates of Phytophthora cactorum recovered from apple plants identified the presence of diversity in pathogenicity. These isolates appeared pathogenic to tested apple trees. It revealed that Golden Delicious, Star Crimson and the rootstock MM106 were more susceptible than Richared and Red Delicious cultivars, but with variable levels of aggressiveness according to physiological stages of tested segments of apple plants. Necrosis caused by Phytophthora cactorum isolates was more important on shoot segments than on wood segments. %K Crown rot %K apple tree cultivars %K Phytophthora cactorum %K pathogenicity %K physiological stages %U http://docsdrive.com/pdfs/ansinet/ja/2006/321-325.pdf