ABSTRACT The sugarcane aphid (SCA), Melanaphis sacchari (Zehntner) became a perennial pest of grain sorghum in the United States beginning in the summer of 2013. Susceptible grain sorghum has been considered one of the most optimum hosts utilized by SCA although it is widely known that other grass species used for grazing, haying and silage also serve as hosts. We evaluated the reproductive capacity, preference/non-preference, and feeding damage caused by SCA on eleven forage and grass species, including pearl millet, proso millet, forage sorghums, sorghum x Sudan grass hybrids and a related grass, Saccharum ravennae. The study was conducted on younger plants, infested one week after emergence, and an identical evaluation was conducted by infesting at two weeks post emergence, with both experiments carried out for five consecutive weeks post-infestation. Sorghums, sorghum-sudangrass forages such as TX 7000, SPX 46214, SPX 49313, Trudan and Sordan supported a high reproductive potential and were highly preferred over millets sp., wheat and barley. The sorghums, sorghum-sudangrass forages sustained the highest damage ratings when the plants were infested at one week and two weeks of age. Sugarcane aphids had a mid-level reproductive potential on millets Leafy 22 and Millet 32 when plants were infested at one week of age but were lower in aphid numbers at two weeks of age. Millets were not as suitable in terms of hosting sugarcane aphids when compared to the sorghums. Barley Aberdeen 812, soft red winter LA 841, and millet Parakeet did not support any sugarcane aphids when infested at two weeks, and thus are not considered sustainable hosts. These findings identify the forage grass species that could be used in the sorghum production regions that would help reduce threatening populations of the sugarcane aphids and demonstrates the need for developing resistant SCA sources for Sudan and sorghum-sudangrass forages.
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