Population dynamics and seasonal incidence of two Tephritid fruit fly species in mango ecosystem under off-season fruiting in Tamil Nadu

The population dynamics of two Tephritid fruit fly species-Bactrocera dorsalis Hendel and Bactrocera correcta Bezzi-was studied in an off-season fruiting mango ecosystem at Pappanoor of Krishnagiri district in Tamil Naduduring January-December 2018. The population fluctuation of fruit flies in the mango orchard was recorded as fly catches in methyl eugenol traps at successive fortnightly intervals in fixed locations. The B. dorsalis population was found to gradually increase from first fortnight of April (at 6.5 flies/trap/fortnight) and reached its first peak during first fortnight of July (with113.5 flies/trap/ fortnight). Later a second peak in the B. dorsalis numbers occurred in the second first fortnight of September (80.0 flies/trap/fortnight). In case of B. correcta, the first peak was observed during second fortnight of May (15.5 flies/trap/fortnight) and a second peak at first fortnight of September (15.0 flies/trap/fortnight). Where after the B. correcta population started declining to reach the lowest numbers in second fortnight of December (2.0 flies/trap/fortnight). Three weather parameters together tended to influence the trap catches of B. dorsalis and B. correcta to the extent of 48 and 53 per cent, respectively. The significance of these results in future local management of fruit fly populations is indicated.