TY - JOUR AU - Olson, William H. TI - Effect of environment on reproduction in dusky-veined walnut aphids JF - California Agriculture JO - Calif Agr Y1 - 1975/05/01 VL - 29 IS - 5 SP - 10 EP - 11 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://www.ucanr.edu/sites/calagjournal/archive/?article=ca.v029n05p10 AB - The dusky-veined walnut aphid, Panaphis juglandis (Goeze), appears in three distinct forms: alate viviparous parthenogenetic females, apterous oviparous females, and alate males. Commonly, only the alate viviparous parthenogenetic female form of this aphid can be found during the spring and summer months. The apterous oviparae and males appear during the fall. This suggests that temperature, day length, or host plant (English walnut) condition influences form.