Just when you’re set 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. Give them attention now to help ward off insects and diseases, says Ashley Thompson, an Oregon State University Extension Service fruit tree specialist.
“You want to use products that have low toxicity and won’t cause a lot of problems for the environment,” she says. “Dormant sprays score pretty well.”
Applying dormant sprays—horticultural oil, copper and sulfur—helps control nasty pests and diseases, such as codling moths and apple scab.
Superior oil, also called horticultural oil, is a highly refined miscible oil—up to 99.9% pure. When mixed with water and sprayed on trees, it smothers 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, such as apple and pear scab and peach leaf curl.
Copper is a fungicide and bactericide that controls such diseases as 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, the oozing of bacterial-infested honeylike sap from split bark. In a rotation of copper and sulfur, the copper deals with bacteria. Sulfur targets 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.
The trio of pesticides, which can be used in organic gardens, fits into the realm of 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.
Ashley says dormant sprays are an important part of good integrated pest management.
“Their toxicity level for animals is pretty low if you follow the labels,” she says. “Horticultural oil kills target insects, but beneficial insects are rarely around trees
in the dormant season.”
Information courtesy of Oregon State University Extension Service.