TY - JOUR AU - Michelbacher, A. E. AU - Oatman, Earl TI - Walnut aphid studies in 1955: Experimental systemic aphicide OMPA has outstanding promise but more studies needed before release for commercial use JF - California Agriculture JO - Calif Agr Y1 - 1956/03/01 VL - 10 IS - 3 SP - 9 EP - 14 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://www.ucanr.edu/sites/calagjournal/archive/?article=ca.v010n03p9 AB - The 1955 infestations of the walnut aphid were exceedingly severe in certain areas, such as Linden. By early May, the average number of aphids found—on the next to the terminal leaflets—in some orchards exceeded 50.