Timing and efficacy of insecticides for control of mussel scale, Lepidosaphes ulmi, on apple using predictive models

► A method of monitoring mussel scale has been devised. ► A previously published model for the prediction of mussel scale crawler emergence has been improved. ► A strategy for timing of insecticide applications has been determined. ► A number of insecticides have been identified as being efficacious for the control of mussel scale on apple.