Verticillium biguttatumを用いたRhizoctonia solaniによるテンサイ苗立枯病および根腐病の生物的防除

概要

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Twenty-three isolates of Verticillium sp. were obtained from cultivated field soils inoculated with Rhizoctonia solani 5 times at 2 weeks intervals. These 23 isolates had different levels of suppressiveness to damping-off of sugar beet caused by R. solani AG2-2-IV in pot tests. Two isolates (HV8 and HV10) were selected as the most effective. In pot tests, the isolates were more effective in reducing damping-off and the colonization of sugar beet seeds by R. solani with higher concentrations of isolate-infested wheat-bran vermiculite Czapek-Dox culture. An almost similar level of control was attained by applying 5% wheat-bran vermiculite Czapek-Dox culture of the isolates in the total soil and 40 ppm of PCNB. Incidence of root rot was reduced to 45% of the untreated control when Verticillium sp. was applied once to field soil near the tap root of sugar beet one day before inoculation with R. solani (July 9th, 1996). Incidence was reduced to 70% when two more applications were added to nursery soil (April 15th, 1996) and to the planting hole (May 27th, 1996). Light microscopic observation showed that the Verticillim sp. isolates penetrated only living R. solani hyphae stained with 2-(4-lodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride, and infected host cells later died. These isolates were identified as V. biguttatum on the basis of morphology and temperature responses.
日本植物病理学会の論文
2001-04-25