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Dynamics of soilborne Rhizoctonia solani in the presence of Trichoderma harzianum : effects on stem canker, black scurf and progeny tubers of potato
Author(s) -
Wilson P. S.,
Ketola E. O.,
Ahvenniemi P. M.,
Lehtonen M. J.,
Valkonen J. P. T.
Publication year - 2008
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/j.1365-3059.2007.01706.x
Subject(s) - trichoderma harzianum , rhizoctonia solani , biology , canker , inoculation , horticulture , rhizoctonia , damping off , trichoderma , biological pest control , agronomy
Stem canker and black scurf are diseases of potato caused by the fungus Rhizoctonia solani . Spatiotemporal experimentation and empirical modelling were applied for the first time to investigate the effect of antagonistic Trichoderma harzianum on the dynamics of soilborne R. solani on individual potato plants. Trichoderma harzianum reduced the severity of symptoms, expressed as ‘rhizoctonia stem lesion index’ (RSI), during the first 7 days post‐inoculation when the inoculum of R. solani was placed at certain distances (30–60 mm) from the host. For example, with inoculum at 40 mm from the host, RSI was 6 and 40 with and without T. harzianum , respectively. At later observation times, the antagonistic effect was overcome. Trichoderma harzianum reduced the severity of black scurf on progeny tubers. Furthermore, the mean number of progeny tubers per potato plant was reduced by the biocontrol treatment (means of 6·5 ± 1·1 and 9·9 ± 2·7 tubers per plant with and without T. harzianum , respectively), as was the proportion of small (0·1–20·0 g) tubers (48% and 66% with and without T. harzianum , respectively). Additionally, there were fewer malformed and green‐coloured tubers in pots treated with T. harzianum than in those without T. harzianum .