author(s)
G Roy, N Laskar and S Sarkar

abstract
Fruit flies (Diptera: Tephtritidae) are one of the most important insect pests to fruits worldwide. In West Bengal, fruit flies have inflicted considerable yield losses especially in mangos (Mangifera indica L.). However, there has been no recent assessment of the associated economic damage impact despite the outcries from the farming communities. The objective of this study was to determination of intensity of infestation by fruit flies in important fruits of mango, to guide the development and improvement of fruit fly control measures in the mango orchard especially northern part of West Bengal. A survey was conducted in the major mango producing areas of the northern part of West Bengal. The fruits were collected from different location of Cooch Behar, Alipurduar, Jalpaiguri and plains of Darjeeling district. From each locations altogether one hundred (100) fruits were collected randomly at three times i.e. early, mid and late stage of the crop during 2014 and 2015. During 2014, results showed that highest fruit infestation on mango (16.33%) by fruit flies was recorded from Chilkir hat (26⁰53′N, 89⁰19′E) and lowest (7.33%) infestation was noted from Matigara (26⁰72′N, 88⁰38′E). However, in the next year i.e. during 2015, the fruit infestation was recorded higher (15.00%) from Naksalbari (26⁰70′N, 88⁰42′E) and lower (7.33%) was recordedfrom Pundibari (26⁰41′N, 89⁰38′E). Pooled mean of both the years of study revealed highest average infested fruit (13.67%) at Chilkir hat localities while lowest (7.83%) at Pundibari on number basis. It was common to experience 100% fruit losses across the agro-ecological zones in the absence of control measures. The situation was increasingly severest with exotic commercial varieties.