Biological Characteristics and Life Table Parameters of the Sorghum Aphid (Melanaphis sacchari) on Different Sorghum and Sorghum bicolor×Sorghum sudanense Cultivars

Purpose The sorghum aphid, Melanaphis sacchari (Zehntner), is a predominant pest of sorghum, sudangrass, sugarcane, Sorghum bicolor×S. sudanense, it is necessary to clear the effects of growth and development of sorghum aphids on different cultivars.

Method The biology characteristics, development times, nymphal survival rate, and life table parameters were evaluated on 7 cultivars, including TianM81, Sterilelines7050A, Wantianliang No.1, Shendiya, Wancao No.3, Wancao No.4, and GaodanD in the laboratory at 24℃±1℃, 70%±5% relative humidity. The plant hosts were subjected to 14 hours of light and 10 hours of dark. Sorghum aphid successfully survived on all seven cultivars.

Result The mean relative growth rate of sorghum aphid reared on the Shendiya plant was the highest (0.56), while sorghum aphid on the Sterilelines7050A and the Wantianliang No.1 were the lowest (0.33). The developmental times to maturity ranged from 5.35 on the Shendiya to 9.04 days on the Wantianliang No.1. The immature survival rates on the Shendiya, Wancao No.4, and GaodanD were the highest (98%), while the immature survival rate on the Sterilelines7050A was the lowest (80%). The reproductive period of the sorghum aphid was also significantly different between different sorghum and the S. bicolor×S. sudanense cultivars. The longest reproductive period was observed on the Wantianliang No.1 (18.03 days) and the shortest reproductive periods were observed on the Sterilelines7050A (13.59 days). There were significant differences in r_m values among the population of four sorghum cultivars and three S. bicolor×S. sudanense cultivars (P < 0.05). The Melanaphis sacchari reared on the Shendiya, the Wancao No.3, and the Wancao No.4 had significantly higher r_m values (0.330, 0.329 and 0.352 day⁻¹). The lowest r_m value was seen on the Sterilelines7050A (0.245 day⁻¹). The R_o value of sorghum aphid on different cultivars ranged from 57.65-90.95 females⁻¹· generation⁻¹ with significant difference among cultivars (P<0.05).

Conclusion Wancao No.4 is suitable host plants, the Sterilelines7050A and the Wantianliang No.1 are unsuitable, even the Sterilelines7050A and the Wantianliang No.1 are resistant to sorghum aphids among the cultivars.