In field experiments, during two successive fall seasons, the best treatment in reducing aphid population on California Wonder pepper cv. was the use of Actellic followed by Sisi and Shakrona oils. While on Long Red Cayenne the lowest number of aphid was recorded in Sisi oil and Actellic treatments during 1992 and 1993, respectively. The percentage of virus infection, during 1992, was least in alu‌minium foil and white plastic mulching (12-14%) as compared to control (65-74%), whereas in 1993, the two tested cvs. showed low virus infec‌tion percentage (8-10%) with aluminum foil mulching compared to the untreated control (55-60%). On excised pepper leaves previously treated with Sisi oil (1 5 m1/1) the average number of Myzus persicae probes/hr was increased by 46.79%. Also, Sisi oil treatment killed 39.9% of the aphid on plants compared to 10% in untreated control after 24 hr from treatment. On the other hands, M. persicae failed to transmit PVY in the first 3 days when fed on Sisi oil treatment plants and only on the 4th day thet a suc‌cessful transmission occurred. The Sisi oil treatment decreased number of off-springs of aphid by 22.90% after 24 hours from oil spraying.