If you had problems last growing season with insects ravishing some of your favorite trees and shrubs, now is your opportunity to get revenge. Late winter is an excellent time to apply dormant oil. Now that doesn't mean that the oil itself is dormant, it just means that the insects that you apply it to are asleep or in a state of dormancy.
Oils have been used for a long time by orchard growers to get an early start on protecting their fruit crops from pests. But it can also work well on ornamentals you may be growing in your own garden like azaleas or camellias.
Dormant oil is especially effective when it comes to dealing with difficult insects like scale, thripes, mealy bugs and spider mites. The oil actually suffocates insects in their various life stages and it will keep eggs from hatching.
You can find dormant oil wherever garden chemicals are sold. Just follow the directions on the label as far as how much to use. Now when you apply it, be sure and soak the limbs and stems of the plants thoroughly. And if you have had a particularly heavy infestation of insects, you may need to re-apply it several times. Also be sure to apply the oil when temperatures are going to be above freezing for a few days and when the wind is low.
The nice thing about dormant oil is that it allows you to get an early start on insect problems. This will keep you from having to use harsher chemicals during the season, which could have a detrimental effect on beneficial insects.