Abstract:  【Aim】 This study was conducted to monitor the population changes of most dominant species of the peach fruit fly, Bactrocera zonata distributed at seven localities (Sargodha-Ⅰ, Sargodha-Ⅱ, Bhagtanwala, Sakessar, Chak# 75-SB, Chak# 46-SB and Chak# 104-NB) of Tehsil Sargodha from 2009 to 2011. 【Methods】 Population occurrence of B. zonata was recorded on weekly basis using methyl eugenol pheromone traps charged at fortnight intervals. 【Results】 The results revealed that the highest population abundance of B. zonata was recorded at Sargodha-Ⅰ (53.67, 45.82 and 45.47 flies/trap) followed by Sakessar (41.13, 33.87 and 35.75 flies/trap) whereas Chak# 75-SB had the lowest population occurrence (15.78, 19.18 and 19.15 flies/trap) during all the three years (2009-2011), respectively. The highest peaks were observed during April (76.08, 71.94 and 61.51 flies/trap, respectively) followed by May (60.74, 52.63 and 64.00 flies/trap, respectively) and the lowest during February and October each year. Moreover, there were strong positive relationships between the maximum and minimum temperature and B. zonata population abundance where negative association was observed for the relative humidity and rainfall. Similarly regression coefficient demonstrated that the maximum temperature was the major contributing factor influencing B. zonata population occurrence and rainfall contributed the lowest share. 【Conclusion】 Regular inspection of B. zonata population should be carried out throughout the year, especially when temperature started to rise in April-May as weather factors greatly influence population counts of B. zonata.

Key words: Tephritidae, Bactrocera zonata, population dynamics, weather factors, citrus, pheromone trap