Environmental Changes Impacting Tea Pest Biology: Some selected case studies

Abstract

In order to cope up with the environmental changes insect and mite pests of tea, especially (1) Tea Mosquito Bug (2) Looper caterpillars of geometrid moths (3) Red Spider Mite have changed their survival strategies. Occurrence of these pests is largely influenced by the changes in the micro and macro environment, which include: (a) Intensive cropping pattern in tea (b) rise in ambient temperature (c) reduced and changed rainfall pattern (d) deforestation and planting of alternate host plants/shade trees (e) pest population suppression by routine application of synthetic pesticides (f) certain management practices. Pest incidence and colonization of tea is multi-strategic. Some pests invade and colonize tea bushes from other wild hosts, some complete number of generations on tea host , some change their time of incidence, some anticipate pesticide spray and start laying eggs at safer places, some withstand the higher toxic effects of the pesticides and become tolerance/resistance through enhancement of their defense enzyme levels. The challenges thrown up by the pests need to be tackled by restricted surgical strike using spot spray technique of synthetic pesticides, rotation of effective pesticides and application of newer molecules often mixed with synergists or by adopting non-conventional methods. The non-chemical methods may include use of: (a) conservation and release of natural enemies (b) microbial pesticides (virus, bacteria, fungus) (c) plant extracts as herbal pesticides (d) light/pheromone/polythene traps (e) cultural practices (f) combined management of conventional and non-conventional strategies under Integrated Pest Management Program (IPM). Adoption of such combined practices may bring in some long term eco-friendly and sustainable pest management in tea, making the made tea more exportable and acceptable to health-conscious domestic consumers.

Keywords: Environmental influence on Tea Pest Biology