Vol. 10, Special Issue 5 (2021)

Author(s):
N Sathiyamoorthy, K Senthilvel, N Rani, K Ramya and G Ponnudurai

Abstract:
Adult house flies were collected from five poultry farms in different blocks of Namakkal, Tamil Nadu and reared in the laboratory. The second stage larvae obtained from the collected house flies were used for larvicide bioassay. In vitro trials were conducted with different concentrations of Cyromazine (1%) such as 0.025, 0.05, 0.1, 0.2 and 0.25 per cent. Twenty numbers of second stage larvae were seeded into the larval medium (100 g) incorporated with each concentration of drug and the control group with fresh water in a plastic container. The larvae in both groups were maintained at 33±1 ˚C and 60-70 per cent relative humidity with a photo period of 8:16 hours of light and dark period. The larval mortality was assessed 4 days after treatment and pupae, if any were collected and placed in a container for another 5 days to observe adult fly emergence. Data on larval mortality, abnormal pupae, intermediates and adult fly emergence were recorded. The results revealed that hundred per cent inhibition of fly emergence in three farms at the normal recommended dose (0.05 %), indicating that the fly population in these farms were susceptible to this drug and remaining two farms had shown 80-90 per cent reduction of fly emergence even at higher concentration of larvicide (0.1 %) suggesting that the population of houseflies prevalent in these farms might have developed resistance against Cyromazine.