Print this fact sheet by W.S. Cranshaw and B. Baxendale * (12/13) Quick Facts… Certain oils, diluted with water and applied as sprays, can be effective controls of many plant pests. Horticultural oils are usually highly refined petroleum oils combined with an emulsifiying agent. Some plant-derived oils also are used. Advantages of oils include safety, … Continue reading Insect Control: Horticultural Oils – 5.569