Populations of Brachycaudus schwartzi (Börner) were found on peach and nectarine (Prunus persica Siebold & Zuccarini) trees in Parlier, CA, in summer 2000. To determine if this aphid could be a pest of P. persica, a nine-variety host range test was conducted using a no-choice arena and temperature-dependent development studies of the aphid at 15, 20, 22.5, 25, 27.5, 30, and 32.5 C. Nectarine va...