Trioza erytreae Del Guercio (Hemiptera: Triozidae) has been reported to be a major vector of the African huanglongbing, a form of citrus greening disease. In the tropical regions of Africa, factors regulating population changes of the pest within citrus orchards and plantations are almost unknown. This study carried out in an experimental plot of citrus orchard in Yaoundé, Cameroon, aimed at monitoring some climate and edaphic factors, which regulate the population changes of the pest. From January 1992 to December 1993, psyllids were counted weekly on flushing shoots and buds from 65 ten-year-old citrus trees. In 1992, the psyllid population changes revealed eight generations with three main peaks (January–March, April–September and September–December), and only three generations with one peak in 1993 (October–December). Among climate factors studied, higher maximum temperatures and saturation deficit index were negatively correlated with psyllid population. The shoot flushing rhythm within citrus trees was also highly correlated with psyllid population. In 1993, citrus trees were not weeded and no fertilizer was applied, and this led to disappearance of the pest from the plot and to a decreased number of annual generations from eight recorded in 1992 to three in 1993. Results from this study represent an important step towards the citrus psyllid ecology and the development of an integrated pest management programme for its control, with regard to weather conditions, cultural practices and host plant relationships.