Pest dynamics in relation to climate change 

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Plant protection deserves prime importance in crop production because of the fact that potential yield of crops are limited by pest groups of various categories viz., insects, diseases, weeds, nematodes and rodents. Since pests are biotic natural resources of the Earth, their interdependent interactions amongst system variables are equally influenced by the factors of climate change. Climate effects on pests could be direct as well as crop mediated. While the key effects of climate change are on temperature, moisture and greenhouse gases (CO₂ and O₃) leading to the rise of mean annual temperatures, increase in  precipitation with  high variability in rainfall pattern and its  intensity, the impact on  such changes on agriculture would be regionally distinct and spatially heterogeneous. Such changes would have significant consequences on plant and animal ecology.

Changes in spectrum of insect pests, diseases, weeds, natural enemies and antagonists, increased risk of invasion by exotic and migrant pests and pathogens, extension of geographical range, noxious abundances of several species also in higher altitudes, increased overwintering,  altered development, morphology and reproduction, increased number of generations, loss of resistance in cultivars containing temperature-sensitive genes, extension of crop development season causing changes in crop-pest and disease  synchrony, changes in inter-specific interactions at different trophic levels  and decline in chemical efficacy are  some of the projected effects/impacts of climate change.   

Capturing of direct and indirect effects of climate change is crucial for adapting our pest management. Use of  historical crop, climate, and pest/disease and management data vis-a-vis current conditions provide ample and immediate  scope of understanding effects of climate change and plan for adaptive IPM strategies. Another approach towards the understanding of the direct potential effects is to conduct studies at controlled conditions for knowing how intrinsic population growth is related to temperature and   identifying   relationship between temperature, phenology and population growth rates through of appropriate models. Indirect effects of climate change come through the host crop and associated environmental resistance factors on population growth of the pest. Also hazards of outbreaks can be used to assess the effects of climate change on outbreak species.

NICRA recognized the importance of pest risks associated with climate change and provided a research platform across crops of rice, pigeon pea, groundnut, tomato and mango during its first phase of implementation under eleventh plan.  Assessment of the changing pest scenarios, mapping of vulnerable regions of pest risks, and to evolve curative and preventive pest management strategies towards climatic stress have been emphasized among many approaches to study the impact of climate change on pests.

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