We report several laboratory bioassays using different rates of spinosad against Tetranychus urticae Koch (Acari: Tetranychidae) females and larvae. Tetranychus urticae females and larvae were individually placed on bean leaf disks (1 cm diam) with four residual spinosad rates (266, 121, 55, and 25 ppm). Tetranychus urticae females in spinosad treated disks had significantly higher mortality and lower oviposition compared to the water control, and significantly fewer T. urticae larvae completed development at any of the four spinosad rates than the control. In choice tests where half bean leaves were coated with spinosad (55 ppm) transversally or longitudinally, T. urticae females preferred and oviposited on non-spinosad treated areas. When T. urticae females were released on potted bean plants (2-leaf stage) in which leaves received spinosad sprays on the adaxial or abaxial leaf surfaces, or complete spinosad coverage on one or two of the leaves, population increase lagged significantly behind T. urticae females that were released on plants that received a water spray.