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.

ENTOMOPATHOGENS 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.