By: Anne Baley
When you first chose your fruit trees, you probably picked them from a tree catalog. The shiny leaves and gleaming fruits in the pictures are enticing and promise a delicious result after a few years of minimal care. Unfortunately, fruit trees aren’t the carefree plants you might hope they’d be. Pests and diseases affect fruit trees in every part of the country. Spraying fruit trees is the best way to avoid these problems, and they work best when they are done at the right time of the year. Let’s learn more about when to spray fruit trees.
Tips on proper fruit tree spraying times are normally dependent on the types of sprays used. Here are the most common types for spraying fruit trees and the best time for spraying trees to prevent future issues.
No matter what type of spray you’re using on your fruit trees, take care to never use them just when the blooms are opening. This will avoid damaging the bees that are so important for pollination and fruit development.
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CORVALLIS, Ore. – Just when you’re ready for a long winter’s nap, it’s time to tend your fruit trees.
If you don’t, chances are they’ll struggle in the coming season. Giving them attention now helps ward off insects and diseases, said Steve Renquist, a horticulturist for Oregon State University Extension Service who has taught hundreds of gardeners the basics of managing fruit trees.
Applying dormant sprays – Superior oil, copper and sulfur – helps control nasty pests and diseases like codling moths and apple scab.
Superior oil, also called horticultural oil, is a highly refined miscible oil (up to 99.9 percent pure) that when mixed with water and sprayed on trees will smother overwintering insects and their eggs. It targets mites, aphids, leaf hoppers, mealy bugs, leaf miners and more.
Sulfur is a fungicide that controls fungal diseases like apple and pear scab and peach leaf curl.
Copper is a fungicide and bactericide that controls diseases like bacterial blight, fire blight and Nectria canker. It kills bacteria and fungal spores left in the trees, including Pseudomonas syringae, a common bacteria that can cause gummosis, which is oozing of bacterial infested honey-like sap from bark split. In a rotation of copper and sulfur, the copper will deal with bacteria and sulfur will target fungal diseases best.
With a spray regimen of all three – used in conjunction with good hygiene and pruning practices – most fruit tree problems can be nipped in the bud, according to Renquist.
The trio of pesticides, which can be used in organic gardens, fit snugly into the realm of IPM or integrated pest management, a practice that uses a variety of low-risk tools to deal with pest problems and minimize risks to humans, animals and the environment.
“They are a really important part of good IPM,” Renquist said. “When you’re planning a program, you want to use products that have low toxicity, and won’t cause a lot of problems for the environment. Dormant sprays score pretty well. Their toxicity level for animals is pretty low if you follow the labels. Superior or horticultural oil kills target insects, but beneficial insects are rarely around trees in the dormant season.”
A good reference for disease and pest control is Extension’s Managing Diseases and Insects in Home Orchards, which has a list of cultural practices and least toxic products for various pests and diseases.
Renquist recommends a three-pronged approach to spraying. In fall around Thanksgiving, apply copper. Spray sulfur in early January and then at least two weeks later make a spray with dormant oil. Then make another copper spray in mid-to late February. Don’t combine copper and sulfur or sulfur and oil in the same tank to minimize the risk of damage to tree bark.
If you don’t like to spray or forget the early spray, Renquist said the January application is the most important. This year, if you’ve missed the January timing, you’re still better off to make the third spray.
An application of lime sulfur solution during from late December to early January helps reduce the risk of over-wintering mildew on fruit trees during the dormant growth months. This is also a suitable time to spray peach trees to prevent leaf curl disease. Peach trees usually require three applications of lime sulfur three weeks apart for full protection. An application of horticultural oil with the lime sulfur spray gives fruit trees even more coverage against pest and disease problems.
Jennifer Loucks has been writing since 1998. She previously worked as a technical writer for a software development company, creating software documentation, help documents and training curriculum. She now writes hobby-based articles on cooking, gardening, sewing and running. Loucks also trains for full marathons, half-marathons and shorter distance running. She holds a Bachelor of Science in animal science and business from University of Wisconsin-River Falls.