Egyptian Alfalfa Weevil (EAW) pose great danger in recent years of alfalfa cultivation areas inEl-Farafra Oasis,New Valley governorate, a crop that has an important role in combating desertification in terms of soil stabilization and increase fertility in modern reclamation areas, the population density of damaging stages of the EAW, Hypera brunneipennis (Boh.) in standing Alfalfa was estimated by conducting periodic survey during two successive years. Aestivated weevils migrated from aestival shelter by the last week of November and its population attained the maximum by the third week of March. Larval stage appeared during first and second week of February 2016 and 2017 respectively and lasted until the start of May. Population size of developing adults was closely correlated with larval population. Peaks of larva and newly emerged weevils occurred on 3^st and 20^th March 2016 and came one and two weeks later in 2017. All weevils developed in summer were obliged to enter summer diapauses (aestivation) during mid-May the influence of prevailing high temperature and long days. The effect of weather factors viz: daily mean temperature, daily mean relative humidity and day-length on the population density of adult, abundance and summer diapauses was statistically discussed. This recent study proved that the insect had one generation in the field per year.