Vegetable, Fish and Mineral Oils Control Grapevine Powdery Mildew

Abstract

Laboratory, greenhouse and field experiments were performed on vegetable, fish and mineral oils to evaluate their phytotoxic effects on grapevine and their effectiveness in the control of grapevine powdery mildew. None of the oils tested showed detectable phytotoxic effects at concentrations of 2% or less applied up to 4 times per week. In greenhouse trials, the efficacy of paraffin oil, refined rapeseed oil and partially refined fish oil against powdery mildew was similar to that obtained with the standard fungicides (tebuconazole or colloidal sulphur). In field trials, the three oils tested (paraffin oil, crude soya oil, and fish oil: 1% in aqueous emulsion) were at least as effective as the standard fungicide Quinoxifen, with crude soya oil being the most effective. The oils used in the field trials were also effective for controlling eriophyd mites such as Calepitrimerus vitis.