Monitoring of the pest population round the year is one of the most important basic information in formulating IPM concept for sustainable agriculture. The study aimed to investigate the seasonal fluctuation of the adult fly round the year for two successive seasons 2008/2009 and 2009/2010 through the use of cue-lure traps with referring to their affecting by the main weather factors such as temperature (minimum and maximum) and mean relative humidity at Assiut Governorate. Significant variation in occurrence of the pest was recorded during the period of investigation. During warm months the flies were more active as compared to that of cold weather period (December, January, and February) months. Significant positive correlation (r) of fly incidence was noted with maximum and minimum temperature (r = 0.395 and 0.413 respectively) with the fruit fly catch per trap for the first year 2008-09 and (r = 0.243 and 0.280 respectively) for the second year 2009-10. However, in relative humidity negatively correlated for two years (r = -0.218 and -0.182 respectively) recorded with the fly catch. The efficiency of these factors were minimum temperature came first, relative humidity and maximum temperature came second or third in its efficiency. Results of the present investigation may be utilized in chalking out sustainable pest management strategy in the agro-ecological system under consideration.