TY - JOUR AU - Michelbacher, A. E. AU - Hitchcock, Stephen TI - Frosted scale on walnuts: Codling moth treatment, DDT drift from adjacent crops interfere with control of the pest by natural enemies JF - California Agriculture JO - Calif Agr Y1 - 1956/04/01 VL - 10 IS - 4 SP - 11 EP - 15 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://www.ucanr.edu/sites/calagjournal/archive/?article=ca.v010n04p11 AB - Frosted scaleon walnuts—held in check by natural enemies—was almost an unknown problem in northern California until after DDT was used to control the codling moth.