Dormant oils have been used since the late 1800s to control a wide range of insect pests on fruit and shade trees. They have a faithful following because they are safe to apply and degrade quickly in the environment. Additionally, they are valuable because of their compatibility with many other IPM controls and particularly because they are less harmful, than other pesticides, to non-target beneficial insects. Dormant oils have many different names. Some are called superior oils, supreme oils, petroleum oils or horticultural oils. All are a light-weight oil that is pale amber in colour with little odour.
Dormant oils are used to control overwintering and exposed soft-bodied insects and eggs of aphids, mealybugs, mites and scales that attack many different species such as dwarf Alberta spruce, roses, junipers, Mugho pines, magnolia, lilacs and euonymus.
The low toxicity of this product makes it safe to use for humans and most wildlife
The window for dormant oil spraying is in early spring once temperatures rise above freezing and prior to bud break or late fall after leaf drop. Some products can also be used in the summer during active growth.