The division
conducts basic and applied research on the biology,
ecology and control of insect and mite pests
of tea. Appraisal of crop loss due to major
pests, establishment of economic threshold levels,
bioecology of pests and its natural enemies,
studies on the use of behaviour modifying chemicals,
botanicals for pest control, developing cultural,
biological and chemical control strategies and
estimation of pesticide residues and heavy metals
are the major areas of research.
BIOECOLOGY
AND CROP LOSS
Most
of the tea pests are highly seasonal; many attack
tea only during dry season while a few are abundant
in wet weather; there are a few perennial pests
too. Data are available on the bioecology and
crop loss caused by major pests such as pink
and purple mites, thrips, tea mosquito and shot
hole borer. Red spider mite (RSM), Oligonychus
coffeae has emerged as an important
pest of tea in the last few years. Studies on
its population ecology showed that the incidence
of RSM was high during January to May and low
during June to December and reached a peak in
March / April. Crop loss studies revealed that
the mite can cause more than 18 % loss in crop
when the infestation is severe.
E
NTOMOPATHOGENS
IC FUNGI
for pest control is an important new
area of research. Occurrence of an indigenous
strain of Beauveria bassiana
(Balsamo) on shot hole borer was investigated
and the fungus has been made available as a
wettable powder (BIO-POWER) formulation for
the control of shot hole borer of another Prepathogen,
Paecilomyces fumosoroseus (Wise)
was reported as recently. The fungus was evaluated
for its efficacy against the red spider mites
in the lab and field with encouraging results.
The entomopathogen is now available wettable
powder formulation under the commercial name
of “Mycomite” for the control of
red spider mite.
STUDIES
ON BEHAVIOUR MODIFYING CHEMICALS
Another important area of research on semio-chemicals
attracting
the
shot hole borer. While conducting studies on
alternate host
plants of shot hole borer, cut stems of a jungle
plant, Montanoa bipinnatifida
C. Koch were found to attract shot hole borer
beetles. Large scale field experiments were
conducted at Valparai to find out the possibilities
of using the cut stems of this plant as a trap
for shot hole borer. The study showed that 22
to 28 days old cut stems measuring 90 cm long
and 25 to 30 mm thickness attracted large number
of adult beetles. The number of beetles attracted
to the stem trap was more during June to October
with a peak in July. On an average of four cut
stems were required for an area of 100 sq. m
and approximately 400 cut stems needed per hectare.
The number of beetles attracted to the stems
declined after 15 to 20 days indicating the
need for replacement of cut stems. Volatiles
extracted from partly dried Montanoa stems were
analysed in Gas Chromatograph coupled with Mass
Spectrum. In all runs compounds belongs to monoterpene,
sesqiuterpene and cyclodiene groups were found.
Blends of theses compounds were tested in the
lab and field with encouraging results.

Sex
pheromone of Helopeltis was studied. The volatile
compounds released by the unmated females were
extracted and subjected to Gas Chromatograph
– Mass spectrum studies. Compounds involved
in the attraction and their composition were
identified. Olfactory chemo sensillla situated
in the antennae of the bugs showed largest response
to certain mixtures in Electro Antennogram (EAG)
studies.