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Evaluation of a strain of Myrothecium roridum as a potential biocontrol agent against Phytophthora cinnamomi

Potential antagonists of Phytophthora cinnamomi were evaluated from among 36 fungi and 110 bacteria isolated from the rhizosphere of avocado roots growing in a soil suppressive to Phytophthora where P. cinnamomi had been present for 40-50 yr. Strain TW of Myrothecium roridum proved to be the most ac...

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Bibliographic Details
Published in:Phytopathology 1989-10, Vol.79 (10), p.1079-1084
Main Authors: Gees, R. (University of California, Riverside), Coffey, M.D
Format: Article
Language:English
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Summary:Potential antagonists of Phytophthora cinnamomi were evaluated from among 36 fungi and 110 bacteria isolated from the rhizosphere of avocado roots growing in a soil suppressive to Phytophthora where P. cinnamomi had been present for 40-50 yr. Strain TW of Myrothecium roridum proved to be the most active antagonist in controlling P. cinnamomi in repeated greenhouse pot tests with highly susceptible seedlings of Persea indica inoculated with P. cinnamomi. M. roridum was grown on a wheat-bran medium and introduced into a peat-perlite mixture at 2.5% (w/v) 2 wk before inoculation with P. cinnamomi. In a UC-mixture with P. indica inoculated with zoospores of P. cinnamomi, M. roridum suppressed root infection by 50-94% compared with uninoculated controls. In the same experiments there was no significant difference in the level of control achieved by either M. roridum or the fungicide potassium phosphonate (2.5 mg/pot). In three naturally infested field soils, root infection ranged from 12 to 54% in the presence of M. roridum, compared with 58 to 93% for controls over the same 4-wk period. On a selective medium containing carbendazim, a fungicide-resistant mutant of strain TW, TWm14, was isolated consistently from the root tips of P. indica growing in infested soil 4 wk after transfer, demonstrating the apparent rhizosphere competence of this strain in all three soils
ISSN:0031-949X
1943-7684
DOI:10.1094/Phyto-79-1079