Efficacy of cultural methods in the control of rhizoctonia solani strains causing tomato damping off in Kenya
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Date
2014Author
Muriungi, SJ
Mutitu, EW
Muthomi, JW
Language
enMetadata
Show full item recordAbstract
Rhizoctonia damping off of tomato caused by Rhizoctonia solani can be a serious
problem in most intensive production environments. Recent increase in smallholder
vegetable production of 0.5-3.0 ha in Kenya has resulted in build up of the pathogen
to above economic threshold levels. There is no effective chemical control or resistant
varieties. Use of soil fumigants such as methyl bromide in the control of Rhizoctonia
and other soil borne pathogens is not sustainable due to their high costs, and toxicity
to man and environment. Cultural methods such as soil amendments, mode of
planting and influencing soil moisture levels either alone or in combination with other
methods are among the most likely substitutes to use of toxic fumigants for control of
soil borne pathogens in agriculture. This study was undertaken to evaluate the effects
of cow manure application, transplanting, planting on raised beds and varying
watering interval on Rhizoctonia damping off of tomato as measured by percent
seedling survival at 5-30 days after planting (DAP), disease severity at 30 DAP,
percent crop stand at 60 DAP and fruit yield at maturity. The study was conducted in
a field artificially inoculated with pathogenic strains of Rhizoctonia solani isolated
from infected tomato plants and Rhizosphere soil sampled from the major production
regions of Kenya. The efficacy of the various cultural strategies both singly and in
combination on the Rhizoctonia damping off management was compared with the
conventional disease control involving chemical fumigation with metham sodium and
two chemical seed dressers (pencycuron, thiram, imidacloprid) and (captafol) as the
standard. Cow manure application and shorter watering interval when used singly or
in combination with other cultural methods produced lower disease control and yield.
Transplanting, planting on raised beds and medium irrigation interval when used
singly or in combination with other cultural strategies produced good disease control
resulting in higher yield that compared favorably with the conventional disease
control involving soil fumigation and seed dressing. The various cultural disease
control methods documented in this study can be used alone and in integration with
other compatible Rhizoctonia damping off of tomato control strategies. Furthermore
the promising non-chemical strategies may form part of the urgently sought for
alternative to use of hazardous fumigants in agriculture and since they are not
specific, there is low risk of resistant development over time