Impact of weather parameters on the population dynamics of fruit flies (Tephritidae: Diptera) in mango orchard of Krishnagiri district, Tamil Nadu, India

Abstract

Population dynamics of the Tephritid fruit flies-Bactrocera dorsalis Hendel and Bactrocera correcta Bezzi were studied in mango ecosystem at Gangaleri location in Krishnagiri district of Tamil Nadu during January to December 2018. The relationship of weather factors to population fluctuation of adult fruit flies in mango orchard was assessed in trap catches at fortnight intervals in fixed locations. The populations of B. dorsalis started increasing from first fortnight of April (12.5 flies/ trap/ fortnight) and reached the first peak (96.0 flies/ trap/ fortnight) in the second fortnight of June. Thereafter B. dorsalis catches gradually declined (with 77.5 flies/ trap/ fortnight) from first fortnight of July and reaching the lowest level (of 3.00 flies/ trap/ fortnight) during second fortnight of December. While the relative population of B. correcta was lower, it started increasing from first fortnight of April (from 3.0 flies/ trap/ fortnight) to also reach the first peak in second fortnight of June (13.5 flies/ trap/ fortnight),whereafter the catches declined from first fortnight of July (7.0 flies/ trap/ fortnight) with the catches reaching the lowest level (0.5 fruit flies/ trap/ fortnight) during second fortnight of December. Correlation studies with weather parameters showed that they together tended to influence the trap catches of B. dorsalis to an extent of 46 per cent, whereas catches of B. correcta were apparently not correlated with weather factors. The potential utility of these results in local fruit fly management is indicated.