Journal of Tea Science Research. 2015, Vol. 5, No. 7, 1-6
2
root disease pathogens such as
Poria
and
Fomes
, have
been effectively eradicated by soil fumigation. Soil
fumigation with methyl bromide has been extensively
carried out for the control of fungal pathogens
(Venkata Ram and Joseph, 1974). The plant protection
equipments were also developed in the 80’s. The
performance and efficiency of hand operated dusters,
and sprayers were continued to improve the current
decade, making chemical treatment against pest and
diseases increasingly effective. There has been a very
substantial improvement in the performance of
motorized air – blast spraying equipment from the
60’s to the 70’s. For the tremendous research and
valuable contributions of late Dr. C.S. Venkata Ram,
he is commemorated every year in the form of the
annual tea colloquim organized by UPASI. He is
celebrated as a very strong role model for young tea
researchers through his own research life and career.
The inspiration from him draws every researcher to
give his energy and contributions to the betterment of
tea research. His research has been the building base
of every research conducted in the division. He
glittered in the UPASI as its former Plant Pathologist
& Director. It is a privilege for Pathology division for
his tremendous research in tea diseases and
management which has saved the south Indian tea
plantations from extinction.
Plant Pathology and Microbiology research
activities
In Plant Pathology division, research is done on
diseases of tea and their management. Blister blight is
the most important foliar disease of tea. Extensive
research has been carried out on the pathogen’s life
cycle, epidemiology and control measures. It is a
credit to the division that the timely control measures
developed in the fifties saved the south Indian tea
plantations from being wiped out by this disease.
Based on the epidemiological studies, a computerized
model has been developed for predicting the incidence
of blister blight disease. So far, several fungicides
have been screened against the disease, and the
efficient ones were identified and recommended for
use. Studies are under way to find out alternatives for
chemical control measures and biological control
strategy is one among them. Importance is also being
given to the studies on resistance of plants to this
pathogen. Studies on systemic acquired resistance
(SAR) and induced systemic resistance (ISR) are
being carried out. Understanding the biochemical and
molecular basis of resistance can bring out effective
strategies for disease control in future and already
research work has been initiated. Forecasting model
was developed for controling blister blight disease
of tea (Premkumar
et al
.,2002). Extensive research has
been done on grey blight and brown blight diseases,
which are other important foliar diseases of tea. After
screening several fungicides, the effective ones have
been recommended for field application. Recently, a
number of bacterial and fungal strains have also been
identified which antagonize the grey blight pathogen
and also reported as new foliar fungal diseases
(
Cylindrocladium
sp. and
Alternaria alternata
).
Wood rot and Branch canker are important stem
diseases of tea in southern Indian tea plantations.
Almost the entire population of old Assam seedlings is
affected by these diseases which resulted in yield
stagnation. Both the pathogens are wound pathogens
and they gain entry through the wounds present in the
tea bushes mostly sunscald injuries. Selective surgery
and protection of wounds by applying copper
oxychloride paste was the common practice followed
in the control of stem diseases. Recently, this practice
has failed due to copper oxychloride deleted from the
list of approved chemical in tea plant. In this scenario,
biological control integrated with chemical control of
plant pathogens have been considered as potential
control strategy in recent years. Native bacterial bio
control agents were isolated from tea ecosystem and
checked for their bio efficacy against wood rot and
branch canker diseases under
in vitro
and
in vivo
.
Proven strains (ten strains) were made in to a
consortium which was found to be effective against
wood rot and branch canker diseases. The consortium
is very much compatible with agrochemicals. The
consortium is commercialized and the marketing
rights have been given to a commercial laboratory
(TARI organic tea special). The influence of the
climatic factors on the severity of the wood rot disease
was critically assessed at monthly interval under
field
conditions. High ascospore production of
Hypoxylon
serpens
occurred during monsoon period. Low
