TY - JOUR AU - Madsen, Harold F. AU - Hoyt, Stanley C. TI - Woolly apple aphid control: Upward and downward migration of aphid throughout trees reduced in preliminary experiments with chemical compounds JF - California Agriculture JO - Calif Agr Y1 - 1956/03/01 VL - 10 IS - 3 SP - 6 EP - 14 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://www.ucanr.edu/sites/calagjournal/archive/?article=ca.v010n03p6 AB - Continual movement of the woolly apple aphid throughout the tree is one of the major difficulties in its control.