Population dynamics of the Asian citrus psyllid Diaphorina citri Kuwayama was studied in two-week intervals throughout the season on lemon in a citrus orchard in Southern Baluchistan, Iran. Population peaks were observed in March, April and September 2007 to January 2008. Population levels were positively related to the availability of new shoot flushes, which were in turn related to the weekly minimum temperature. Also, the nymph population peaks were observed in three periods (beginning of March, end of August and end of January). Results indicated that moderate climatic conditions coupled with the flushing of citrus trees are two main factors for an increase of the development and activity of nymphs resulting in pest population increase, while extremes of both high and low temperatures, low relative humidity and high rainfall were detrimental. Four coccinellids (Coleoptera: Coccinellidae), one syrphid (Diptera: Syrphidae), two parasitoids (Hymenoptera) and two spiders (Araneae) were determined as natural enemies of the psyllid in the studied area.