Relative susceptibility of cereals and pasture grasses to the yellow sugarcane aphid (Homoptera: Aphididae).
The survival and reproduction of Sipha flava on numerous cool- and warm-season grasses, legumes, and forbs was studied to establish the relative susceptibility of the host plants. S. flava survived on 21 of 21 warm-season grass species, 32 of 32 cool-season grass species, 3 of 19 legume species, and 1 of 4 species of forbs. However, final aphid means of some plant species were lower than the initial infestation. Based on aphid population development, Bromus mollis [Bromus hordeaceus], B. biebersteinii, B. marginatus, Agropyron dasystachyum [Elymus lanceolatus] and A. intermedium [E. hispidus] were the best hosts among the cool-season grasses. Echinochloa frumentacea, S. bicolor and Pennisetum orientale were the best warm-season grass hosts. Legumes and forbs were essentially non-hosts of the pest. In a separate but related test, the intrinsic rate of increase values (rm) of the aphid was determined on 8 species of grasses, Hordeum vulgare, Triticum aestivum, and S. bicolor. The rm values for the aphid were significantly higher on Bothriochloa caucasica, Dichanthium sp., S. bicolor and Digitaria ciliaris than on the other entries. Higher rm values were related to shorter prereproductive time, greater aphid fecundity, and increased longevity. The aphid had the lowest rm values on Sorghum halepense, Panicum virgatum and Andropogon gerardii.