This study aimed to reveal some biological effects of black fly Aleurolobus marlatti (Hemiptera: Aleurodidae) on Christthorn. The research work was conducted in Baghdad during the period extending from June 2015 to March 2016. The purpose was to count the number of black fly A. marlatti’s generations, the appearance period, the overwintering insect and the appearance date. The results showed that the adult appearance began in the last week of March in the field. The generations were marked by insect population that fluctuated between highs and lows. Generations were analyzed both on an annual and monthly basis depending on fluctuations in temperature and relative humidity. The number of insects were noticed in the form of eight peaks representing eight generations per year in central Iraq.