NEEM SEED OIL INHIBITS APHID TRANSMISSION OF POTATO-VIRUS-Y TO PEPPER

Transmission of potato virus Y to sweet pepper by the green peach aphi d, Myzus persicae (Sulzer), was inhibited by foliar applications of 1. 0% or 2.0% neem seed oil to infected source plants or to uninfected re cipient plants. Neem seed oil interfered with virus acquisition and in oculation in a manner comparable to that of a commercial horticultural oil, while an oil-free neem seed extract did not reduce rates of tran smission compared with controls. The finding that neem seed oil inhibi ts virus transmission, while oil-free neem seed extract does not, sugg ests that the presence of the oil rather than biologically active limo noids such as azadirachtin interfere with virus transmission. None of the treatments affected rates of infection when potato virus Y was tra nsmitted mechanically, or the resulting virus titre and symptom expres sion. In addition to direct control of insect pests, formulated neem o ils may help reduce or delay the spread of non-persistent plant viruse s.