Variation in the Pathogenicity of Eutypa lata (= E. armeniacae)

Abstract

Evidence is advanced for the existence of pathotypes in Eutypa lata. Two groups of pathotypes, respectively of high and low virulence to apricot, were identified on the basis of the uniform patterns of response obtained following the inoculation of single ascospore isolates to four cultivars of apricot in widely separated geographical regions. These pathotypes exhibited similar patterns of virulence to almond, in which there was some evidence for differences in the susceptibility of cultivars. Of the six isolates inoculated to pear, only one was pathogenic. The grapevine is believed to be a universal host, susceptible to a wide range of pathotypes of which only a few are capable of pathogenesis in hosts in which the pathogen is found infrequently.