Studies on the Turfgrass Snow Mold Caused by Typhula ishikariensis 4.Biological Control of Typhula ishikariensis on Bentgrass with an Antagonistic Bacterium.

Abstract

An isolate All ofPseudomonas fluorescens, a bacterium antagonistic toT. ishihariensis, was isolated from sclerotia of the latter fungus which was harvested from golf courses. The difficulty existed in distinguishing this specific isolate from a large population of the nativeP.fluorescenswhich is a common habitant in the turf when this isolate was sprayed on to the turf. To survey the survival rate of sprayed All in the turf, a daughter isolate, named A11RN, which was tolerant to both rifampicin and nalidixic acid was induced from the parent A11 colonies on media including these antibiotics. The sod-cup test suggested that 4×10⁸cfu/cm²of All and All RN in culture liquid suppressed mycelial growth of T. ishihariensis.
The spray of All and A11RN in culture liquid to golf courses effectively suppressed the snow mold disease caused byT.ishihariensis. These suppressive effects were higher than those of the fungicide and increased with the elevated densities of the sprayed isolates. An isolation test showed that A11RN, which had been sprayed to the turf of golf courses just before a snow season, survived in the turf until the end of April of the next year, although its population gradually diminished before the snow melted. The present experiments proved that All would be a candidate to develop a new, commercial antagonistic microbe complex, which is effective to control the snow mold in golf courses.