If you have had an insect infestation, and are worried it will return to plague your fruit, shade and ornamental trees, dormant oil can be applied in late winter and early spring.
Dormant oils work to choke off insects where they over-winter inside trees. Some oils poison the pest insects, but leave many beneficial insects alone. Dormant oils, which are typically made from organic material, are safe to use on most plants, and around areas frequented by children or pets.
There are some oil-sensitive plants like junipers, cedar and maple the cannot tolerate dormant oil. Check with a Garden Shop representative if dormant oil is right for you.