Thermal impact on thripstabaci, lindeman (thysanoptera; thripidae) and their role in the onion agro market of india. a case study conducted at ramgarh (Jharkhand, India)

Climatic factors and especially the heat play the most significant role in the life cycle and their reproduction, life span and feeding habits of insects .Increase in climatic temperature increasesthe rate of growth and increase the population similarly in cooler condition slow down the development of species .The studied pest Thrips tabaci Lindeman (Thysanoptera ,thripidae ) is a serious onion pest of Ramgarh it causes both direct and indirect destruction to onion crops and resulting high loses in onion production .The climatic condition of Ramgarh is suitable for onion cultivation. The growing consciousness in people to words the onion consumption and always high marketing price promote the farmers to intensification of onion cultivation. This cash crop destroyed by Thrips tabaci .The adult pest and their nymphs lacerate the surface tissues of the foliage, puncture the leaves and suck the exuding sap ultimately the whole plant dries up and the size of the bulb reduced to small. Increase in climatic temperature directly influence the increase in Thrips tabaci population and development of new young leaves of onion plant also. The population growth of pest is due to the availability of vigorous green sap content and maximum hiding places suitable for continuous breeding. Moderate temperature and highhumidity leads to grow new leaves which is full of nutrients for the pest. Migration of pest to surrounding crops and weeds occurs due to decline in availability ofgreen sap it is due to the senescence of crop plant. Thrips tabaci Lindeman (Thysanoptera ,thripidae ) is a serious pest of onion at Ramgarh .Serious infestation decline 40% to 50% onion production . The pest not only decline the quality quantity and nutritional value of onion but also the marketing rate of onion. The control of pest population and infestation is very difficult so the farmers are advised to apply synthetic insecticides for rapid relief Carbaryl 0.1% or Monocrotophos 0.03% or Dimethonate0.03% are effective. Some natural enemies as small birds, ants, mites etc. also control the pest population. Seranisus sp. are also use it parasitized the nymph and control the pest population.