The best way to treat any problem is to take steps to prevent it from happening in the first place. This is true when it comes to caring for your trees. Take preventive measures to protect your trees against bug infestations by applying horticultural oils to the twigs and branches during the dormant season.
Because they are often applied during the late winter dormant season (February and March), horticultural oils are often referred to as “dormant oils”. While the dormant season is most common for applications, certified arborists will sometimes prescribe their use during the growing season, too.
How Do Horticultural Oils Work?
Horticultural oils are very thin and highly-refined oils that are mixed with water and then sprayed on trees and shrubs. These oils kill pests and their eggs that are over-wintering on trees and shrubs by cutting off their supply of oxygen. The mode of action is mostly physical which means the material provides one of the safest and most effective control options. Insects cannot develop a resistance to oil and the material is benign to beneficial insects and spiders.
Horticultural oils control a wide range of overwintering insects including many scale insects (found mostly on oaks, maples and pines) and spider mites.
When To Use Horticultural “Dormant Oil” Treatments
Dormant season applications are preventative and will control overwintering eggs and insects, while applications made during the growing season target pest that have already hatched and may be actively feeding. While dormant season applications are most effective and pose little risk to the tree, growing season applications may cause tip burn or leaf curl if applied improperly.
As with all tree care treatments, always read the instructions and contact a professional before applying dormant oils. You want to keep your trees safe and if you are unsure how or when to apply, call a professional arborist.
Call A Professional
It is advised to call a professional tree care company like Hansen’s to schedule a hassle free plant health care and diagnosis consultation. They can determine if, and when, dormant oils should be applied to your trees.