Locust: weather event for swarm
International pest for india.
Locust are able to travel long distances and colonize new habitats. Therefore, their distribution is variable in time and space and can occur within a large area . The pest is feared for both its destructive capacity and its constant threat to region . It is capable of sudden appearances and severe devastation to standing crops. The most affected part of the world is continent of Africa, where in some years the the infested area may cover several million hectares. Distribution and sequence of rainfall is the principal determinant of locust population increase over several generations and of the concentration of widespread populations into highly mobile and destructive swarms. Survival and populations are greatest with an increased frequency of sufficient rainfall where rainwater is enhanced by runoff and flooding, and where vegetation and soils provide suitable habitats. However excessive rainfall affects the 1st three nymphal stages, limiting its development. Locust move in swarms from one area to another where rain has fallen .
Wind direction and speed at 850 hpa (about1.5km above the earth's surface)and convergence zones determine the paths of locusts' movements. In Indian subcontinent, monsoon rainfall and ,to a certain extent, winter spring rainfall play a vital role in the resurgence establishment and termination of locust plague upsurges.
Locust avoid thermal extremes by taking refuge in appropriate sheltering sites,loss of water by flying during favourable climatic conditions, and cannibalism.
Breeding region for locust-
There are two distinct breeding regions for the locusts,1st that Spring breeding regions,which received rainfall in winter (January to April) and the summer breeding region, which receives rainfall during may to July .
India comes under summer breeding region.the ascent of the locust swarm from the breeding sites and descent in the area of convergence are regulated by upward and downward air currents respectively.
Regards Graceful Guidance for Dr-GK Das SIR HOD Agrometeorology and Director of seed farm IGKV RAIPUR
Courtesy -sujeet sumer
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