Journal of Tea Science Research. 2015, Vol. 5, No. 7, 1-6
4
tea plantations. Further, public awareness on the
pollution problems caused by fungicides and their
failure due to resistance build up stressed the need for
developing integrated disease management strategies
through the integration of cultural, biological and
judicious application of fungicides. This measure is
eco-friendly and towards sustainable agriculture for
the implement of IDM technology against tea diseases.
Major contributions in the management of tea diseases
have come up during the past several decades in
disease management which have revealed the efficacy
of biocontrol agents like
Trichoderma
and
Gliocladium
with suboptimal level of fungicides in controlling
stem diseases like collar canker (Ponmurugan and
Baby, 2007), thorny stem blight (Chandramouli and
Baby, 2002), red root (Baby et al.,
2004) and wood rot
disease (Nepolean et al., 2014). The potential of
phylloplane bacteria in controlling blister blight
disease has also been reported (Baby et al., 2004) in
tea plantations for implementation of IDM technology.
Surveys were undertaken in different tea growing
zones of southern India for collecting diseased
specimens and beneficial microorganisms. The indigenous
wood rot and branch canker causal organisms were
identified through molecular tools. A total of 645
bacterial and 40 fungal strains were isolated. The
isolated bacterial and fungal biocontrol agents were
screened for their antagonism against tea pathogens.
Efficient strains have been identified as
Bacillus
sp.
(WR46-2 & HBCWR-3),
Pseudomonas
sp. (WR5-4),
Bacillus
sp.
(AGBB21)
, Alcaligenes faecalis
(MBC-8,
MBCP-7, WRP-4, WRPV-4),
Bacillus weihenstep-
hanensis
(MBC-2),
Brevundimonas diminuta
(VPFWB)
and
Pseudomonas geniculata
(WRPV5) through
molecular techniques. An
in vitro
the study was
carried out on growth inhibition of pathogens using
several chemical fungicides and plant extracts. Proven
biocontrol agents and plant extract of
Artemisia
nilagirica
were sent to the Indian Institute of Crop
Protection (IICPT) in order to identify their bioactive
compounds which inhibit the growth of tea pathogens
using GC-MS analysis. Based on molecular
confirmation studies, the indigenous brown blight
pathogen was isolated and identified as
Glomerella
cingulata
in tea collected from south Indian tea
plantations. The Endomopathogenic fungus (
Beauveria
bassiana
) was isolated from infected tea mosquito.
Proven strains of four actinomycetes were isolated and
identified as
Streptomyces crystallinus
(APSA1),
Streptomyces flavogriseus
(AAS7)
, Streptomyces
albus
(CAS4)
and
Streptomyces
xanthocidicus
(APSA4) from tea soils. Three bacterial biocontrol
agents were identified as
Pseudomonas
fluorescens
,
Bacillus
amyloliquefaciens
and
Bacillus
subtilis
against branch canker pathogen. Plant aqueous
extracts of
Allamanda cathartica
,
Psidium guajava
,
Acorus calamus
,
Azardirachta indica, Curcumma
longa
,
Murayya koenigii
and
Carica papaya
were also
tested at 5, 10 and 15% against branch canker
pathogen
.
Leaf powder of
Acorus calamus
even at the
lower dose (5%) inhibited the growth of branch canker
fungus followed by
Curcumma longa
,
Murayya
koenigii
,
Azardirachta indica
and
Psidium guajava.
Compatibility studies of bacterial and fungal
biocontrol agents with various agrochemicals used in
tea were completed. Studies on mass multiplication of
biocontrol agents were carried out. Three days old
liquid bacterial biocontrol culture (LB) and five days
old fungal biocontrol culture (PDB) were mixed with
sterile talc powder separately, which was suitable for
field application. Straight application of
Pseudomonas
sp.,
Trichoderma
sp. and consortium of
Bacillus
sp
and
Pseudomonas
sp. provided good control of grey
blight disease under field condition. While considering
the integrated approach, the combination of
Pseudomonas
sp. and
Bacillus
sp. (5 kg/ha.) with
recommended chemical fungicides (half dosages)
efficiently controlled grey blight disease with 50%
reduction in use of chemical fungicides. In the pruned
fields, combined application of
Bacillus
sp. (100g /
bush) with recommended chemical fungicides at 0.5%
as wound pasting (1:1 ratio) were effective for
integrated management of wood rot and branch canker
diseases. Such integrated schedules did not affect the
quality of made tea manufactured from leaf samples of
treated plots. This study strengthens the concept of
integrated management of grey blight, wood rot and
branch canker diseases in tea. Efficient biocontrol
agents are being maintained in germplasm of UPASI
TRF, TRI Valparai. Proven bio control agents were
also commercialized for implementation of integrated
