As it grows, a cherry tree, like most fruit trees, may experience issues caused by pests or diseases. Things such as location, weather and upkeep determine which problems your trees will encounter and how well they stand up against them. And your first line of defense is to buy disease-resistant cherry trees.
But routine good practices are also helpful, including adequate watering, fertilizing only as needed, seasonal pruning, preventive and active spraying, fall cleanup, and winter protection.
Cherry tree diseases are caused by bacteria, fungi, and viruses. The diseases can spread through the soil, water, air, infected tools, animals, insects, and even gardeners themselves.
Spot diseases on your cherry trees sooner so you can treat plants before they are destroyed by disease and can successfully manage symptoms. Here is a three-step approach to keeping vigilant about the presence of cherry tree diseases:
- Research the risks. Find out about cherry diseases that are prevalent in your geographic area. When possible, buy disease-resistant cherry tree varieties to avoid diseases in the first place.
- Examine trees daily. Check your cherry trees every day to be sure no disease symptoms are present or emerging.
- Spot diseases early. Catch and treat disease quickly so your plants can recover and thrive. Throw away or burn infected branches instead of composting them to prevent diseases from coming back to your garden via the compost.
Here are some of the diseases you may spot on your cherry trees.
Armillaria Root Rot (aka Mushroom Rot)
This smells distinctly like mushrooms and occurs on the upper roots and/or crown of the tree. This fungus can live for up to 30 years. Look for whitish-yellow fan-shaped mats between the bark and wood. Dull, yellowed, or wilted foliage is the first sign of trouble.
Control it manually by exposing the infected crown and upper root area of the tree. In spring, remove soil around the base of the tree to a depth of 9 to 12 inches and keep the area clean and dry throughout the life of the tree.
This appears during a cool, wet season on ripening fruit as brown spots that become brown spores. The fungus will overwinter in the soil and in plant debris.
Control this by spraying with an all-purpose or fruit tree fungicide, or with horticultural or neem oil.
This is another fungal disease that occurs mostly after a long, warm, wet spring. It is one of the most common cherry tree diseases, though not fatal. It is easy to spot: Look for blossoms that turn brown and wither but stay on the tree.
You may also see small sunken spots at the base of infected blossoms, which may seep gummy brown sap. Leaves at the twig ends appear shriveled. Furry gray or beige mold forms on affected blossoms or twigs, and the fungus spreads rapidly to the fruit.
You can spray (preventively, if brown rot is common in your area) with an all-purpose or fruit tree fungicide, or a natural copper fungicide. To prevent, plant a resistant variety, prune regularly to keep trees open to light and air circulation, and remove pruning debris, damaged or diseased fruit and limbs, as well as fallen fruit. Disinfect your pruners between cuts.
Buckskin (X Disease)
This is spread by some leafhopper species and is managed by planting disease-free stock and controlling weeds that host leafhoppers. Look for leathery, bumpy fruit that is pale in color even at harvest time.
Pull off infected twigs and limbs where cankers appear. Cut out cankers that are less the half the branch circumference using a small, sharp knife and scoring the wood all around the canker. Maintain a 1-inch margin around the canker.
Slip the knife under the bark and remove the diseased, rusty brown inner bark. Round the edges of each incision to promote rapid healing, but don’t remove the wood from uninfected areas.
Clean up chips and debris and burn or dispose of it in the trash. Bleach your knife. Apply fungicide spray to small wounds during wet or dormant periods.
Canker attacks trees via weak or injured bark and tends to occur during cool, wet weather. Treat cankers the same as you would for buckskin disease cankers (above). You can also use a multi-purpose fungicide, or a natural spray such as copper fungicide or horticultural oil.
Crown gall is caused by a bacterium that lives in the soil and causes rapid, abnormal growth (galls). It can spread through injury to roots in the soil as well as through infected gardening tools.
Infected trees will appear stunted and slow-growing, and leaves may be small. In fruit-bearing trees, there may be no more fruit. Look for woody, tumor-like growths, especially at the crown and below.
To prevent this disease, buy gall-free nursery stock and handle trees carefully to avoid injury. Crown gall symptoms can appear on the roots, trunk, and branches, so inspection of nursery stock is important.
Phytophthora Root Rot and Crown Rot
This appears if the soil around the base of the tree remains wet for a long time, or when the tree is planted too deeply. Infected trees usually wilt and die quickly once the weather warms up. Leaves may turn dull green, yellow, or red or purplish.
Dark areas appear in the bark around the crown and upper roots. Gummy sap may ooze from the diseased trunk, and reddish-brown areas may show between the bark and wood.
Prevent this disease with good water drainage. Never cover the graft union of dwarf trees with soil and try to avoid direct watering of the crown. Carefully cut away affected bark at the soil line. Trees may be saved by removing soil from the base of the tree down to the upper roots and allowing the crown tissue to dry out.
You may use a multi-purpose fungicide on these rots.
The fungus that causes this overwinters in buds and emerges during warm, humid weather. Look for whitish-gray powdery mold or felt-like patches on buds, young leaves, and twigs. Leaves may crinkle and curl upward, and new shoots are stunted.
Control powdery mildew with a multi-purpose fungicide or natural sprays such as horticultural spray, copper fungicide, or neem oil.
Tip: Make your own natural disease and pest control spray with benign materials. Mix one tablespoon of baking soda, 1/2 teaspoon of a mild dish detergent, and 2 1/2 tablespoons of olive oil in a gallon of water to make a solution that will repel all kinds of bugs and serve as a fungicide. Shake it well in your bottle before spraying and repeat every week for it to be continuously effective.
We’re believers in not using toxic materials in the garden—they can hurt the plants, hurt the soil, damage the environment, and harm you.
Have you had problems with diseases attacking your cherry trees? What types of problems do you regularly face with your trees? Please tell us how you treat and prevent diseases from destroying your cherry crop.