Influence of abiotic environmental factors on incidence of melon fruit fly (Bactrocera cucurbitae Coq.) on bittergourd

Abstract

Bittergourd (Momordica charantia L.) is an  important vegetable crop cultivated exten sively in the subtropical and tropical coun tries. For cucurbits, especially bitter gourd,  the melon fruit fly (Bactrocera cucurbitae Coq.) damage is the major limiting factor in  obtaining good quality fruits and high yields  (9). Extent of yield loss caused by the pest to  cucurbitaceous vegetables ranged from 30 to  100% depending upon cucurbit species and  the season in different parts of the world (4).  The melon fruit fly activity varies a lot de pending mostly on the prevailing climatic  conditions and the diversity of other hosts in a  particular agro-ecosystem (3). In view to de termine the appropriate time of action and  suitable management practices to be adopted  regular crop pest surveillance and monitoring  needs to be developed. Keeping these facts in  mind, study was carried out on periodicity of  occurrence of melon fruit fly in relation to  various abiotic environmental factors as a  help to evolve an effective and economical  strategy of management. The experiment was  conducted at the Incheck farm, ‘C’ Block,  Bidhan Chandra Krishi Viswavidyalaya  (BCKV), Kalyani, Nadia, West Bengal which  was located at 22.50 N latitude and 88.220 E  longitude at an elevation of 9.75m above sea  level during two consecutive years i.e. 2010- 2011 and 2011-2012 from the December fort night to March fortnight. Local variety,  Medinipore Garbeta was replicated two times  of plot size 8m2(2m×4m) with a plant spacing  100cm × 40cm following all agronomical  practices excluding plant protection. Observa tions on incidence of melon fruit fly was re corded on the basis of number of fruits dam aged by the pest at seven days interval at early  hours during the whole period of crop grow ing season. Maggots per infested fruits were  counted. These data were later converted to  maggot population per fruit with formula used  by Barma and Jha (2).