Dormant oils are used in integrated pest management (IPM) to control insect populations on trees and plants.
Benefits include less environmental impact and better preservation of beneficial insects to the woody plant.
Dormant oils increased in popularity over the past 50 years as homeowners and property managers looked for more natural and eco-friendly ways to control undesirable insects.
Successful tests indicate a solid correlation between applying dormant oil and a decrease in populations. In turn, fewer contact general spraying with pesticides was required.
Also referred to as horticulture oil or emulsifying spray, dormant oils have been used for centuries to stop insects in the scale family from attacking fruit trees.
Dormant oils in Denver are very effective on needle scale on pine trees.
Back East they are effective against scale on Apple and Crabapple trees, hence their long usage history.
Dormant oil works by entering tiny holes in the trees known as spiracles and smothering insects and their eggs while they overwinter in the tree.
Recently, neem oils, made from India’s neem tree, gained popularity as a more natural dormant oil.
Advanced distillation techniques have created a new family, called horticulture oil, that can be applied in summer without staining nearby trees.
Despite the hopes of customers who want true organic options, dormant oils are not considered organic.
Dormant oil leaves little residue in your yard – and most arborists agree that it’s much greener than other types of sprays. They can stain dark surfaces such as a deck, so apply carefully.
If you manage a particularly large property that has tens or hundreds of trees it should be the cornerstone of preventive measures.