Avdhesh KumarThakur, Manju2019-11-292019-11-292005-06http://krishikosh.egranth.ac.in/handle/1/5810136412The syrphid flies (Diptera:syrphidae)are one of the most diverse flies of the world ,comprising about 200 genera and over 5000 species .Hoverflies adults display wide range of lifestyle and adaptations. Adult of aphidophagous species are frequent flower visitors ,certain species are predominantly nectarivorous, whereas others are pollinivorous .Adult require honeydew or nectar and pollen to ensure reproduction ,whereas larvae require aphids to complete development syrphus sp. has been observed as the major insect pollinators associated with mango, pollination of flowersrequire insects. The mango belongs to the family Anacardiaceae which is a dicotyledonous family consisting of 64 genera. cross pollination occurs in mango flowers therefore a pollinizer is required. The effective insect pollination is essential for good fruit set and yield in mango (Mangifera indica) Present investigation was therefore, initiated to assess the role of syrphid flies as major insect pollinators in fruit set of mango. For this purpose 30 years old mature mango trees c.v. Dashehari were selected and 20 panicles were bagged. 3 panicles in one bag 0, 5, 10, 15, and 20 syrphid flies were released into each bag respectively at the time of peak bloom. At the time peak bloom different insects were collected with the help of hand net and identified. The activity of syrphid flies was also observed. The number of syrphid flies per panicle, the number of flowers visited per minute and the time spent per flower were checked. Further the role syrphid flies in fruit setting quantity was assessed by counting the number of fruit set and fruits matured in all the six treatments. The quality parameters were determined by testing for the TSS content, fruit size, fruit weight, amount edible pulp. The quantity parameters were determined by testing the number of fruits at different sizes viz. pea size, marble size and full size fruits. The highest number of insects visiting the mango flora belonged to the family syrphidae. Six species Syrphus corollae, Episyrphus balteatus, Melanostoma orientale, Eristalis sp., Ischiodon scutellaris, Syrphus isaaci were found frequently in Pantnagar and were found as the efficient pollinators of various agricultural, horticultural, ornamental, oil seed crops. The highest number of flies were observed between 0900-1000 h, they spent more time per flower an visited maximum number of flowers early in the morning between 0700-0800h. In fruits, that were set under open pollinated conditions where syrphid flies population was maximum, high results were obtained with TSS, fruit size and fruit weight while low results with seed size and peel. Thus, it can be concluded that syrphid flies has greatest potentialities for use in controlling of aphid pests of crops in Pantnagar.ennullThesis