International Journal of Bioassays : IJBNHY : 2278-778X Open Access International Journal of Bioassays 7.6 (2018) pp. 5652-5658 *Corresponding Author: Wajid Hasan Krishi Vigyan Kendra, Jehanabad, Bihar Agricultural University, Sabour Bhagalpur India E-mail: entowajid@gmail.com DOI: http://dx.doi.org/10.21746/ijbio.2018.7.6.1 pg. 5652 Research Article Investigation on population fuctuation of cucurbit fruit fies, Bactrocera cucurbitae associated with cucurbit crops Sohrab 1 , C.S. Prasad 1 , Wajid Hasan* 2 1 Department of Entomology, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, U.P., India 2 Krishi Vigyan Kendra, Jehanabad, Bihar Agricultural University, Sabour Bhagalpur India Received: 9/20/2018; Revised: 10/05/2018; Accepted: 10/06/2018 Available online: 13 th October 2018 Abstract: The population of cucurbit fruit fies, Bactrocera cucurbitae of bitter gourd was observed vary much changeability at Block Daurala, District Meerut. Decreasing temperature negative effect was observed in cucurbits fruit fies population at District Meerut but positive effect of temperature was observed in cucurbit fruit population at District Saharanpur. Fruit fies population of cucurbits fruit increased with the increase of relative humidity, rainfall and decreased temperature while negative relationship was observed with maximum correlation in cucurbits in zaid and Kharif. Moderate to high negative correlation coeffcients were observed between maximum temperature and population fuctuation of cucurbit fruit fies in cucurbits at both places. The signifcant positive and negative correlation coeffcients were present between relative humidity, rainfall and temperature and percentage of fruit fies population. Keywords: Fruit fies, Methyl eugenol trap, Correlation, Population Introduction Cucurbits are infested by several insect pests which are considered to be the signifcant obstacles for economic production. Among them, cucurbit fruit fy is the serious pest responsible for considerable damage of cucurbits [1]. The cucurbit fruit fy Bactrocera cucurbitae can attack about 16 different types of cucurbit crops. Although the rate of attack varies among the crop, infestation reduced both the yield and quality of the cucurbit fruits. Yield losses due to fruit fy infestation vary from 19.19 to 69.96% in different fruits and vegetables [2]. The major constraint to sustainable increased productivity of cucurbits is the high incidence of insect pests. Cucurbits are infested by a number of pests such as cucurbit fruit fy, red pumpkin beetle, epilachna beetle etc. Among them cucurbit fruit fy, Bactrocera cucurbitae (Coquillett) is a devastating pest of different cucurbit vegetables in many parts of the world which may cause more than 60% yield loss [3] . Depending on the environmental conditions and susceptibility of the crop species, the extent of losses varies between 30 to 100%. In India, 31.27 per cent damage in bitter gourd and 28.55 per cent to watermelons [3]. Whereas, either partial or complete damage of above 60 percent of cucurbit crops [4]. The major constraint to sustainable increased productivity of cucurbits is the high incidence of insect pests. Cucurbits are infested by a number of pests such as cucurbit fruit fy, red pumpkin beetle, epilachna beetle etc. The pest has been reported to damage about 81 host plants and as a major pest of cucurbitaceous vegetables, especially the bitter gourd, musk melon, snap melon, snake gourd, ridge gourd etc. The pest has been reported to damage about 81 host plants and as a major pest of cucurbitaceous vegetables, especially the bitter gourd, musk melon, snap melon, snake gourd, ridge gourd etc. The tribe decinae with the genus Bactrocera is of great economic importance in India. Among Bactrocera spp., B. dosalis (Hendd), B. corrcetei (Bezzi), B. zonata (Sounders) and B. cucurbitae (Conquillelt) are of immense economic signifcance. Due to its nature of infestation, it is very diffcult to control the pest. A cluster method have been developed and suggested by to control these pests [4]. Among all these methods, the chemical control method is still popular to the Indian farmers because of its quick and visible results. First three species mainly attack fruit crops, while B. cucurbitae attacks cucurbits. The increasing use of synthetic insecticides has led to a number of problems such as development of resistance to insecticides in some insect pests, high insecticide residues in market produce, resurgence or increased infestation by some insect species due to the destruction of natural predators and parasitoids, changing pest status of mites and other minor insect pests, ecological imbalance and danger to health of the pesticide applicator.