Effect of different temperatures on the growth and development of sorghum aphid (Melanaphis sacchari)

This study examined the effects of different temperatures on the development and fecundity of the sorghum aphid (Melanaphis sacchari). The growth and development, fecundity, and life table parameters of sorghum aphids were studied at 15~30 ℃. The results indicate that the mortality of sorghum aphids is higher at 30 ℃; so no specific data could be generated at this temperature. The growth period of the sorghum aphids were markedly shortened when the temperature increased. Within the range of 15 to 28 ℃, the growth period of the sorghum aphids was between 5.63~12.13 d and the survival rate was between 88%~94%. The survival rate of the nymphs was the highest at 15 ℃ and the lowest at 28 ℃. The weight of the adult aphids and that of the F1 progeny decreased with increasing temperature. The longevity of the sorghum aphids ranged from 11.76 to 48.47 d. The reproductive rate was positively correlated with temperature. In the range of 15~28 ℃, the net reproductive rate of the population ranged from 42.60 to 80.56, with the highest rate recorded at 24 ℃ (80.56) and the lowest at 28 ℃ (42.60). The average generation time decreased with increasing temperature. The intrinsic rate of increase of the sorghum aphids ranged between 0.160~0.339, with the highest value recorded at 24 ℃. In the range of 15~28 ℃, the intrinsic growth rate significantly increased with increasing temperature. Using an equation relating the net reproductive rate, the intrinsic rate of increase and temperature, the optimal temperature for the growth and reproduction of the sorghum aphids was determined to be between 20.34~26.85 ℃. The above results indicate that the growth and development of the sorghum aphids occur optimally at 24 ℃. The population of the sorghum aphids increase when the temperature ranges between 20.34~26.85 ℃ Therefore, within this temperature range the population dynamics of the sorghum aphids can be predicted, which provides the foundation for strategies to prevent the spread of the sorghum aphids.