Effects of various oils on survival of Myzus persicae Sulzer and its transmission of cucumber mosaic virus on pepper

Abstract

Mineral oils are widely used to control non-persistently transmitted viruses by aphid vectors, but mineral oils cause a number of problems including significant phytotoxicity. This study comprises three series of assays to compare a mineral oil, a fish oil and four vegetable oils for: a) insecticidal effects on the aphid Myzus persicae; b) inoculation of cucumber mosaic virus (CMV) by M. persicae to oil-sprayed pepper plants; and c) acquisition of CMV by M. persicae from oil-sprayed pepper plants. The vegetable oils tested were raw and refined rapeseed oil, and raw and refined soya oil. The oil showing the strongest insecticidal activity was raw soya oil (about 50% mortality at 72 h). Refined soya oil, both rapeseed oils and fish oil also showed appreciable insecticidal activity (30-40% mortality at 72 h).The oils most effectively suppressing inoculation were the mineral oil and the refined rapeseed oil, both of which suppressed inoculation entirely. All the oils except the raw soya oil and raw rapeseed oil suppressed acquisition entirely. These results point to the possible utility of vegetable oils, particularly refined rapeseed oil, for control of aphid-transmitted viruses in horticultural crops.