Occurrence and Pathogenicity ofDrechslera teresIsolates Causing Spot-type Symptoms on Barley in Western Australia

Abstract

D. teres, the cause of spot-type symptoms on barley (H. vulgare), is reported from Australia for the 1st time. Spot-type isolates were similar to net-type isolates of D. teres in conidial morphology and colony characteristics. Western Australian spot-type isolated differed from Canadian spot-type isolates in pathogenicity on 2 barley cultivars. A high degree of resistance to spot-type isolates was rare, and only CI 6225 and CI 9214 were resistant to both spot-type and net-type isolates. The common occurrence of spot-type isolates in the northern wheat belt of Western Australia may be the result of widespread use of the susceptible cultivar Clipper, which is field-resistant to net-type isolates of D. teres.