Effects of humidity on the development of the silverleaf whitefly, Bemisia argentifolii bellows and perring (Homoptera: Aleyrodidae)

The effects of humidity on the development of immature stages of Bemisia argentifolii were investigated at 30, 40, 60 and 80% relative humidity (RH), 28 °C and photoperiod of 12L: 12D. Results showed that an increase in RH not only shortened the developmental time for the 1 st, 2nd and 3rd nymphal stages but also increased significantly the body length of the immature stages of B. argentifolii. The sex ratio (female: male) were 2.3:1, 3.3:1, 0.3:1 and 1.6:1 at 30, 40, 60 and 80 % RH, respectively. There was low correlation between sex ratio and humidity (R2 = 0.117), indicating that in the case of B. argentifolii, sex ratio does not attempt to respond to variable levels of RH. The relative humidity also affected significantly the developmental time of the 1st (from 4.20 to 2.22 days), 2nd (from 4.03 to 2.30 days) and 3rd (from 6.00 to 5.95 days) nymphal stages of B. argentifollii (F = 18.055, 0.991 and 15.637, respectively at P 0.05).