Missed dormat applications #546081 - Ask Extension


Missed dormat applications #546081

Asked March 07, 2019, 3:33 AM EST

The weather has been so bad up here on Mt Hood this winter that I'm just getting to my first application of oil/sulfur and it's 1st week into March but my trees are not budding yet. Should I apply a copper application in a couple of weeks if my trees are still dormant or ... since it's so late, skip that application?

Washington County Oregon

Expert Response

So long as your trees are dormant it is not too late to start your spray program.

Copper spray is effective against a number of diseases that attack fruit trees.

The active ingredient in copper sprays is listed on the label as metallic copper equivalent. Products with higher percentages of MCE are more effective. Other ingredients in the spray help the product stick to the sprayed surface and spread. Some extensions warn that some copper sprays don't contain enough fixed copper to control leaf curl. The product you choose to control this disease should contain 50 percent copper. Copper spray should be applied thoroughly. Spray the tree until the product drips from the leaves and stems. To treat fire blight, use a weaker solution every few days until the end of the bloom season.

Copper spray is usually applied during the dormant season. For diseases that affect the blossoms and young fruit, apply copper sprays every few days to every two weeks, depending upon the disease and the fruit affected. This can result in as many as 17 applications over a season for some fruit. The package label is your best source of information about when and how often to spray. Heavy rains can rinse the product from the tree, so use it when you aren't expecting rain.

Using copper sprays over several seasons can cause a buildup of copper in the soil. The buildup eventually becomes toxic to soil organisms, including earthworms. It is also harmful to aquatic species if it moves into bodies of water. Skin exposure can cause pain and itching, and some people become sensitized and experience allergic reactions with repeated use. Wear protective clothing when using copper sprays avoid eye contact by wearing goggles. As with all garden chemicals, store copper sprays in their original container and out of the reach of children.

Don’t expect copper fungicide to cure an existing fungal disease. The product works by protecting plants against development of new infections. Ideally, apply copper fungicide before fungus is visible. Otherwise, apply the product immediately when you first notice signs of fungal disease.

If the fungus is on fruit trees or vegetable plants, you can safely continue to spray every seven to 10 days until harvest. If possible, spray plants when you’ll have at least 12 hours of dry weather following application.

Typically, fungicides are applied at a rate of 1 to 3 teaspoons per gallon of water. However, it’s critical to read the label directions carefully to determine rate of application for each specific product. Reapply the product every seven to 10 days because fungicides degrade after application.

Fungicides are generally not harmful to bees. However, it’s best not to spray when bees are actively foraging on plants. Never apply copper fungicide on very hot days. Never  mix copper fungicides with other chemicals. Never over-apply fungicides.

Hope this helps!


chris Rusch Replied March 08, 2019, 12:15 AM EST

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