As spring turns into summer, our plants develop problems with insects. It seems that every year, there are more pests that attack our plants. There is a way to prevent a lot of these insects from ever appearing on your plants.
The way to eliminate many insect pests is to apply a dormant oil spray to your plants. This is a spray application that you should be doing soon.
In the fall or early winter, many insects lay eggs on plants. These eggs hatch out in the spring, and the insects begin to feed on your plants. In some cases, the insects spend the winter hiding in all the cracks and crevices on the bark of your plants.
Dormant oil is applied when the plants have not begun to put out new growth. The dormant oil is mixed with water and sprayed onto your plants. The oil covers the eggs, and the eggs suffocate. Any over-wintering insects are covered with the oil, and they, too, suffocate.
As I said, the oil spray must be applied before the new growth appears on the plants. In order for the oil to flow properly and get into all those cracks and crevices, the spray needs to be applied at temperatures above 40 degrees.
All things considered, the proper time to apply this spray is during late March through early to mid-April. The length of time you have to apply this spray can vary from year to year based on how quickly temperatures warm up and, consequently, how soon your plants put out new growth.
Fruit trees, rose bushes and many of your other deciduous trees benefit from an application of a dormant oil spray. The vast majority of your evergreen trees and shrubs do not need an application of a dormant oil spray. The exception to this is the treatment of hemlocks to control the woolly adelgid. This cottony-looking insect has resulted in the demise of many hemlocks in this area.