The biological efficiency of a medium-volume (350 l/ha), air-assisted cross-flow sprayer was compared with that of a conventional high-volume (2000 l/ha), hydraulic sprayer for the control of raspberry aphids on red raspberry ( Rubus idaeus) in eastern Scotland, using the contact and stomach-acting insecticide, fenitrothion. After modifications to the position of the spray nozzles, the cross-flow sprayer was nearly as efficient as the hydraulic sprayer at comparable pesticide dose rates. The reliability of control was less with a reduced dose rate. The possibility of savings in application costs is discussed.