Introduction Ecology refers to the study of an organism in relation with its habitat. Ecological agriculture is an agriculture that works with respect to nature. Entomology is "The branch of zoology that deals with the study of insects, including their classification, structure, physiology, behavior, ecology, and evolution."(E.O. Wilson) Uttarakhand is a hill state that lies in northern part of the country. It has varied climatic conditions varying from hills to meadows. Agriculture is a significant contributor to Uttarakhand’s GDP. It is the chief source of livelihood for most of the population. Commercial agriculture is mainly practiced in plains while in hilly regions farmers basically practice subsistence farming. Different crops like rice, wheat, sugarcane, maize, pulses, oilseeds, fruits and vegetables are grown depending on climatic conditions of different areas. Uttarakhand with its unique himalayan terrain and diverse agro – ecosystems, is experiencing significant impacts due to climate change and alterations in climatic conditions like temperature, rainfall and other factors that leads to change in behavioral pattern of insect – pest hinderance and change in their population. Agricultural entomology plays a crucial role in understanding these complex interactions and developing sustainable pest management strategies. Climate change and its impact on the region Climate change has become a matter of great concern in due course of time due to many biotic and abiotic factors that affects humans. The Himalayan mountains are early indicators of climate change, wherein slight changes in climate can lead to a drastic variation in faunal diversity, distribution, invasion of fauna into higher altitudes, rapid population growth, shortening of life cycle and increased number of overwintering species. The insects best represent the faunal diversity. In recent years, due to variation in pattern of rainfall and temperature regimes, several insect pests have moved northwards and are posing great threat to hill agriculture. Few among them are greenhouse whiteflies, thrips and mites in protected cultivation system; blister beetles on flowers of cereals, pulses and oilseeds; invasive insect pests like fall armyworm of maize and tomato pin worm and sporadic pests like grasshoppers that are reaching a status of major key pest in various crops. According to research, Indian Himalayas cover approximately 18 percent of India’s geographical area that accounts for more than 50 percent of India’s forest cover. Agriculture contributes a minor land use in this forest ecosystem with a net sown area of only 10 percent of total area. Climate change is an undeniable fact of present day and its impacts are felt all over the world, but mountains are early indicators of climate change. The rise in air temperature, alterations in precipitation and faster melting of the glaciers have led to increased discharge in rivers and consequent rise in sea level. Some of the documented impacts on mountain agriculture that are linked with climate change in the Uttarakhand, Himalayan regions are: reduced availability of water for irrigation; extreme drought events and shifts in the rainfall regime resulting in failure of crop germination and fruit set invasion of weeds in the croplands increased frequency of insect-pest attacks decline in crop yield Apart from causing direct impacts on crop productivity, climate change is threatening food production in hill agriculture through increasing pest population and their damage potential by expanding distribution, enhancing survivability and allowing adaptability of insect pests to temperate climate. The increase in temperature and decrease in amount of precipitation is leading to altitudinal shift and intrusion of insect pests into high-altitude agriculture lands. Climate change and insect pest dynamics Climate change is also associated with several changes in insect pest physiology and population dynamics like: Changes in diversity, distribution and abundance of insect pests Changes in geographical distribution of insect pests Increased number of overwintering insects Rapid population growth and increase in number of generations. Invasion on new alternative host plants Changes in host plant resistance to insect pests Increased risk of invasive pest species Emergence and dissemination of vector-borne diseases Insects may be beneficial or harmful (pest). According to the study, 2618 species representing 1082 genera, 155 families and 14 orders were identified from the state of Uttarakhand. Beneficial insects help in different ways such as they provide goods such as honey, silk, lac etc.; help in regulating service like pollination; control of pest and diseases and supports in nutrient cycling and decomposition (Diptera and Coleoptera). Major pests of different crops in Uttarakhand hilly areas: Rice Yellow stem borer, leaf folder, case worm, hispa, gundhi bug, swarming caterpillar, thrips, gall midge, and army worm, Rainfed areas - root aphids and white grubs Maize Maize cob borer or earhead worm and the stem borer Early-stage infestation - Termites, ear cutting caterpillars, field crickets and shoot fly, Atherigona falcata Moisture stress srea - cutworm (Agrotis flammatra and Agrotis segetum) Pulses Pigeon pea is infested mainly by pod boring weevil, Apion clavipes, Blister beetle (Myllabris pustulata and M. phalerata) and pod borers (Catechrysops cnejus, Etiella zinkenela and Helicoverpa armigera). Field pea is infested by cut worms (Agrotisipsilon, A. flamerata and Euxoa spinifera), pea semilooper (Plusia orichalsia), pod borers (Catechrysops cnejus and Etiella zinkenela), aphid (Acyrthosiphon pisum), leaf miner (Phytomyza atricornis), Thrips (Megaleurothrips usitatus), Bihar hairy caterpillar (Spilartia obliqua) and stem fly (Ophiomyia phaseoli). The major pest of cowpea is stemfly, aphid, (Aphis craccivora), pod boring weevil and black bug (Coptosoma cribraria). Oilseeds Nacoleia vulgalis, N. diemenalis and stemfly are the destructive pests of soybean. Groundnut is damaged by the Amasacta moorei, A. albistriga, Spodoptera litura. Spilartia obliqua, Aproaerema modicella, Aphis craccivora, Mylabris pustulata, M. phalareta, Monolepta signata, Chaetochnema spp., Epicauta spp. and soil born pests like Holotrichia consanguinea, H. serrata and termites are important. Rapeseed and Mustard are the second most important source of edible oil in the region. Many insect pests are found infesting mustard crop. Saw fly (Athalia lugens proxima), flea beetle (Phyllotruta cruciferae), diamondback moth (Plutella xyllostella), pod borer (Crocidolomia binotalis), cabbage butterfly (Pieris brassicae), aphids (Liphaphis erysimi, Brevicorne brassicae and Myzus persicae) are important. Sesamum is attacked by shoot webber, pod borer (Antigastra catalaunalis), gall fly (Aspondyla sesami) and sphingid moth, (Achaerontia styx) Vegetables Cruciferous - cabbage butterfly (Pieris brassicae, P. candida and P. napae), aphids (Brevicoryne brassicae and Lipaphis erysimi), diamond back moth (Plutella xylostella), cabbage head borer (Hellula undalis), semilooper (Plusia orichalcea), cabbage semilooper (Plusia orichalcea, Trichoplusia ni), cutworm (Agrotis flammatra), flea beetle (Phyllotreta cruciferae), painted bug (Bagrada cruciferarum), leaf webber (Crosidolomia binotalis), cut worm (Agrotis ipsilon) and saw fly (Athalia lugens proxima). Solanaceous Brinjal - fruit and shoot borer (Leucinodes orbonalis), jassid (Amrasca biguttulla biguttula), aphids (Aphis gossypii), white spotted flea beetle (Monolepta signat and Chaetocnema basalis), leaf miner (Phytomyza atricornis) and white fly (Bemisia tabaci) Tomato - fruit borer (Helicoverpa armigera), aphid (Myzus persicae), cutworm (Agrotis ipsilon), jassids (Amrasca bigutulla bigutulla) and white fly (Bemisia tabaci) Malvaceous Okra - fruit and shoot borer (Earias vitella and Earias insulana). The blister beetle (Mylabris pustulata) and oil beetle (Epicauta spp.) jassids (Amrasca biguttula bigittula), semi looper (Anomis flava), (Aconitia graselli), leaf roller (Sylepta derogata), bihar hairy caterpillar (Diacrisia oblique) and fruit bugs (Dysdercus cingulatus and Oxycaraenus hyalipennis) Contributors - Dr. Mayank Kumar, Gunjan Upreti, VSCGUUHF, Bharsar Pauri Garhwal