Studies on stem blight of asparagus caused by Phoma asparagi Saccardo in Saga Prefecture

Abstract

Severe occurrence of asparagus stem blight caused by Phoma asparagi Sacc. was observed from mid-September to mid-October after a typhoon in 1986. The fungus isolated from the lesions was pathogenic to asparagus based on pre-emergence inoculation tests. On the basis of the symptoms observed on the infected plants and shape of the pycnospore formed in the pycnidium, the pathogen of stem blight was identified as Phoma asparagi Sacc. The optimum temperature for mycelial growth of the fungus on potato sucrose agar was 24-25 C. Agar media with potato and asparagus sucrose were suitable for the formation of large pycnidia.