Abstract: The fruit fly (Bactrocera dorsalis and B. zonata) population was monitored with the help of bottle traps containing 100 ml aqueous solution of 0.1% methyl eugenol and 0.25% malathion per trap, in mango and guava orchards of submountainous region of Himachal Pradesh, India. The maximum catch of 98.6 and 62.6 males/trap for mixed population was recorded during 30th and 27th standard weeks in 1992 and 1993, respectively, in mango orchard. The corresponding catch in guava orchard was 427.2 and 517.0 during the 37th and 39th standard weeks. There was a significant positive correlation between the trap catch and maximum and minimum temperatures during both the years for both the hosts. The maximum catch coincided with the ripening period of fruits.