Title : Integrated pest management (IPM) strategies for sustainable tea cultivation
Abstract:
Tea (Camellia sinensis L.) is a major cash crop as well as export commodity of Bangladesh meeting almost the entire domestic demand. Tea plants are subjected to the attack of several insect, mites and nematodes. Globally 1034 species of arthropods and 82 species of nematodes are associated with tea plants. Among them, 25 species of insects, 4 species of mites and 10 species of nematodes are recorded from Bangladesh. Enormous crop loss was incurred due to the attack of these pests and largely responsible for the declining productivity of tea. Management of these pests is an important operation in sustainable tea cultivation. Extensive use of chemical pesticides began only a few decades ago with tremendous immediate economic gains but its abuses were not foreseen or ignored. As a consequence there arose the development of resistance to pesticides, pest resurgence and undesirable pesticide residue in made tea as the major problems. Current trends in eco-friendly insect pest management practices such as cultural control measures like plucking, pruning, shade regulation, field sanitation, fertilizer application, destruction of alternate hosts and selection of pest resistant/tolerant varieties; mechanical mechanisms like manual removal, sticky traps, light traps; use of bio-pesticides, bio-control agents and sex pheromone traps need to be given more importance in pest management programme in tea. Under cultural control measures, light pruning (LP) significantly reduced the infestation of pests of tea other than skiff pruning. Seven days regular plucking round, weeding and field sanitation reduced the incidence of Helopeltis and other foliar pests of tea. Under mechanical control measures, solar power light trap & yellow sticky trap captured greater number of thrips, jassids, white fly, aphids, moths of looper caterpillar and other flying insects in tea plantation. In respect of host plant susceptibility, BT1, BT2 & BT15 clones were found less attacked by Helopeltis. BT5, BT6 & BT17 clones were found less attacked by Red spider mite. BT3, BT4, BT8, BT9, BT12, BT13, BT14, BT15, BT18, BT19, BT20 clones were found less infested by thrips. BT4, BT6, BT7, BT8, BT9 clones were found less attack by termites. Among the botanicals, fresh leaves, succulent stems, seeds of Akonda (Calotropis procera), Basok (Adhatoda vasica), Bishkatali (Polygonum hydropiper), Bhat (Clerodendron infortunatum), Burweed (Xanthium strumarium), Castor bean (Ricinus communis), Datura (Datura metel), Garlic (Alium sativum), Lantana (Lantana camara), Mahogani (Swietenia mahagoni), Neem (Azadirachta india), Nishinda (Vitex negundo) and Tobacco (Nicotiana tabacum) have strong insecticidal properties and can be used as an alternative to chemical pesticides. Bio-control agents i.e. Chrysoperla carnea, Preying mantis, Oligota flaviceps, Oxypes spider, lady bird beetle and Stethorus beetle have been identified as the predators against pests of tea. Erythmelus helopeltidis as egg parasitoid against Helopeltis and Bracon hebetor as a larval parasitoid against looper caterpillar were found very effective. Entomopathogens viz., Beauveria bassiana, Verticillium lecani, Metarhizium anisopliae, Hirsutella thompsonii, Pseudomonas fluorescens and Bacillus thuringiensis were found the toxic on Helopeltis, red spider mite, thrips and looper caterpillar infesting tea and significantly reduced the pest population. Therefore, the developed strong based IPM strategies of major pests of tea will be easily adopted by the planters in large scale for their high return of the production of pesticide free, high value commodities for domestic as well as export markets.
