VIEW ARTICLE

Physiological Races of Venturia pirina on Pear. E. Shabi, Division of Phytopathology, The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel; J. Rotem(2), and G. Loebenstein(3). (2)(3)Division of Phytopathology, The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel Phytopathology 63:41-43. Accepted for publication 13 July 1972. DOI: 10.1094/Phyto-63-41.

Five races of Venturia pirina were isolated from cultivated and wild pears in Israel. These races were found to be specific to five differential hosts of Pyrus communis and P. syriaca origin. Four of these differential hosts were immune to incompatible races; the fifth was sensitive to its compatible race, immune to one race, and resistant to three races. Environmental conditions such as temperature, periods of free moisture on the leaves, and light did not change the specific pathogenic properties in two races on which the environmental influences were tested. In these tests, infection of V. pirina occurred at temperatures from 5 to 28 C with an optimum of ca. 20 C.