Here we are once again in the strange land of horticulture vocabulary. Dormant oil spray. What is dormant oil spray? Do I need it? Do I need to be dormant when I spray it?
No, you don’t need to be dormant, but your trees do. This is one of those things that you need to think about now to make your trees happy later.
Let’s take a look at dormant oil spray for trees, what it does, and why your landscape might need it.
First, What Is Dormant Oil Spray?
Dormant oil spray is an oil-based pesticide and an effective and ecologically friendly way to handle many garden insect pests and even some diseases. Like its name implies, dormant oil spray is sprayed on trees during the dormant season, before flower buds begin to open.
It first became popular as a way to control pest problems on fruit trees. Fruit trees are prone to damaging insects, but traditional pesticides pose a couple problems. One, fruit trees bear edible fruit. And two, pesticides kill all the insects — including the beneficial ones that pollinate the crop.
So an oil-based insecticide was developed for use during the dormant season before the flower buds begin to open. This dormant oil spray kills off any damaging insects that might spend the winter in your trees’ bark, including aphids, mites, and scale.
How Does It Work?
We’ll tell you, but it’s not for the squeamish. The oil coats dormant insects on the tree, smothering them to death before the pests wake up from their winter sleep. The oil blocks the tubes through which insects breathe.
Dormant oil sprays can also kill fungus and diseases that are trapped and growing in the bark, cracks, and crevices of your fruit trees.
When Should It Be Applied?
Timing is crucial. The key word here is “dormant.” It should be applied when trees are in their dormant, resting stage, during the late winter, early spring. It should be applied just before either leaves or flowers show signs of swelling or breaking open.
The temperature is important, too. Oils need the temperature to be above 45 degrees for 24 hours. Otherwise, the emulsion doesn’t hold together and coverage is uneven. If used later in the season in warm weather, the oil can actually damage plants.
Is Dormant Oil Spray For Trees Only?
It can actually damage some trees, including Japanese maple, redbud, and sugar maple. If sprayed on Colorado blue spruce, dormant oil spray can discolor the needles.
So it’s best to consult an expert.
A Few Precautions
Only trees that have had infestations the year before should be treated with dormant oil spray. You don’t want to kill any beneficial insects.
Fungus spores can also overwinter on fallen leaves. So rake and dispose of leaves if you know you have a disease problem.
Let Neave Keep Your Trees Pest-Free
Trees are a long-term investment in your property. You don’t want pests and diseases threatening their long, healthy life in your landscape.
Our professional arborists know what trees are susceptible to what pests and diseases and can expertly craft a plan to keep them happy and healthy.
Give Us A Call.
If you’re in the Hudson Valley, call us at (845) 463-0592. If you’re in Westchester County, call (914) 271-7996; from Connecticut, dial (203) 212-4800. Or, fill out our simple web form, and we’ll contact you about setting up your free consultation.