Economic injury levels for yellow sugarcane aphid (Homoptera: Aphididae) on seedling sorghum

Dynamic economic injury levels were calculated for yellow sugarcane aphid, Sipha flava (Forbes), an occasional pest of seedling sorghum, Sorghum bicolor (L.) Moech. Economic injury levels were based on evaluations of data from five field trials conducted in 1983 and 1984 near College Station, Tex. Multiple regression equations used to calculate economic injury levels related S. flava number, plant spacing, and plant height to yield per plant. Economic injury levels ranged from 3 to 27%, 4 to 43%, and 11 to 100% infested plants for plants 3.5, 4.5, and 5.5 cm tall when control costs ranged from $5 to $25 per hectare and crop values ranged from $250 to $500 per hectare