Pest & Disease Control for Cherry Trees

Cherry Tree Pests

Aphids

Tiny, pinhead-sized insects, varying in color depending on the type. Will cluster on stems and under leaves, sucking plant juices.

Symptoms: Leaves curl, thicken, yellow, and die. Aphids produce large amounts of a sticky residue called “honeydew” that attracts insects like ants. Honeydew also becomes a growth medium for sooty mold.

Control: Spray

• GardenTech® Sevin® Concentrate Bug Killer
• Monterey Fruit Tree Spray Plus

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Monterey Complete Disease Control
• Natural Guard® Neem
• Ferti-lome® Triple Action

Cherry Fruit Fly

Adults are similar in appearance to a housefly, but smaller. Larvae are yellowish-white grubs. Traps are an option for luring adults.

Symptoms: Small, pinpoint-sting marks visible on fruit surface. Eggs are laid under fruit skin. Hatched larvae tunnel, making railroad-like mining pattern.

Control: Spray

• Monterey Fruit Tree Spray Plus

Control: Natural Spray

• Hi-Yield® Vegetable & Ornamental Insect Control
• Monterey Fruit Tree Spray Plus
• Ferti-lome® Triple Action

Moths

Includes: Orange Tortrix, Oriental Fruit Moth, Codling Moth, Winter Moth, Western Tussock Moth, Cherry Scallop Shell Moth, etc.

Adults are moths that vary in size and appearance. Larvae are pinkish-white with a red-brown head, about ½-inch long. Pheromone traps are an option for luring moths.

Symptoms: Damage first appears on vegetative growth, and left untreated will eventually infest fruit. Larvae tunnel in through the stem and often exit near the pit.

Control: Spray

• Monterey Fruit Tree Spray Plus
• GardenTech® Sevin® Bug Killer

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Hi-Yield® Vegetable & Ornamental Insect Control
• Monterey Fruit Tree Spray Plus
• Ferti-lome® Triple Action
• Natural Guard® Caterpillar Killer Spray w/BT

Borers

Includes: American plum borer, Pacific flatheaded borer, Peach twig borer, Peachtree borer, Shot hole borer

Adults are small brown beetles that may target the graft location (in young cherry trees) for laying eggs as well as damaged or sunken areas. Grubs have horseshoe-shaped heads and cream-colored bodies. Difficult to control once infested. Preventative spraying (including the ground around the roots) is a strong defense. Traps – in the form of tanglefoot-coated logs or posts that are later removed from the site and burned – are an option for luring adults.

Symptoms: A thick, gummy substance (sap) leaking from round holes on the trunk or in a crotch of the tree. Grubs tunnel through trunks, weakening and eventually killing the tree. Eggs hatch and larvae tunnel into tree’s vascular tissue.

Control: Manual

• If infested, use a fine wire to try to pierce, mash, or dig grubs out.
• Traps (tanglefoot-coated logs or posts) can lure adults. Remove from site and burn after trapping.
• Preventive spraying (including the ground around the roots)

Control: Spray

• GardenTech® Sevin® Concentrate Bug Killer

Additional Resources

• Contact local county Cooperative Extension for further advice

Japanese Beetle

Adult is a metallic-green beetle, which skeletonizes leaves. Larvae are cream-colored grubs that feed on turf roots prior to maturity. Turf pest-control may help reduce grub populations; check turf product labels for timing and control of grubs. Traps are an option for luring adult beetles.

Symptoms: Adults are often seen in groups – large infestations can cause stunted growth and stress by skeletonizing a majority of the leaves.

Control: Manual

• If infestation is minimal, knock Japanese beetles into a jar of soapy water solution (they will become immobile when frightened as a defense mechanism)

Control: Spray

• Monterey Fruit Tree Spray Plus
• GardenTech® Sevin® Bug Killer

Control: Natural Spray

• Hi-Yield® Vegetable & Ornamental Insect Control

Leafhopper

Small, active, slender-winged insect appearing in various colors. Usually found on undersides of leaves.

Symptoms: Slows new growth; leaves become whitened, stippled, or mottled. Leaf tips may wither and die. Prone to carrying diseases to and from plants and trees; damaged caused by leafhoppers may be greater than the feeding done directly by the insect.

Control: Manual
Hand-removal of webbed foliage and keeping area free of weeds and debris may be enough to manage the pest.

Control: Spray

• Monterey Fruit Tree Spray Plus
• GardenTech® Sevin® Concentrate Bug Killer

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Monterey Complete Disease Control
• Natural Guard® Neem
• Ferti-lome® Triple Action

Mites

Pinpoint-sized arthropods, appearing in many different colors depending on the type. Often found on undersides of leaves.

Symptoms: Sap feeding causes a bronze appearance in leaves. Severe infestations exhibit some silken webbing. Droughts or dry spells are advantageous for mite infestations.

Control: Spray

• Monterey Fruit Tree Spray Plus
• GardenTech® Sevin® Bug Killer

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Monterey Complete Disease Control
• Natural Guard® Neem
• Ferti-lome® Triple Action
• Hi-Yield® Vegetable & Ornamental Insect Control

Scale

Usually on bark of young twigs and branches, encrusted with small (1/16-inch) hard, circular, scaly raised bumps with yellow centers. May also be on fruit.

Symptoms: Sap feeding weakens the tree.

Control: Spray

• Monterey Fruit Tree Spray Plus
• GardenTech® Sevin® Bug Killer

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Monterey Complete Disease Control
• Natural Guard® Neem
• Ferti-lome® Triple Action
• Hi-Yield® Vegetable & Ornamental Insect Control

Tarnished Plant Bug

Yellowish-brown, winged insect that may have black spots or red stripes.

Symptoms: Damage is caused by injecting toxins into buds and shoots, causing stunted vegetative growth and sunken areas (or “cat facing”) on fruit.

Control: Spray

• GardenTech® Sevin® Concentrate Bug Killer
• Monterey Fruit Tree Spray Plus

Control: Natural Spray

• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Hi-Yield® Vegetable & Ornamental Insect Control
• Natural Guard® Neem

Tent Caterpillar

Adults are moths. Caterpillars are a hairy, grayish brown with cream-colored spots or stripes down the back.

Symptoms: Encases large areas in webbing and feeds on enclosed leaves.

Control: Manual

• Remove webs with a rake (caterpillars are removed with webs) and burn.

Control: Spray

• Monterey Fruit Tree Spray Plus

Control: Natural Spray

• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Natural Guard® Caterpillar Killer Spray w/BT
• Monterey Fruit Tree Spray Plus

Thrips

Tiny, slender, fringed-wing insects ranging from 1/25-inch to 1/8-inch long. Nymphs are pale yellow and highly active. Adults are usually black or yellow-brown, but may have red, black, or white markings.

Symptoms: Feeding occurs on vegetation by puncturing and sucking up the contents, causing appearance to be deformed or discolored (similar to damage by mites and lace bugs).

Control: Spray

• GardenTech® Sevin® Bug Killer

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil
• Safer® Brand Insect Killing Soap
• Monterey Complete Disease Control
• Ferti-lome® Triple Action
• Hi-Yield® Vegetable & Ornamental Insect Control

Cherry Tree Diseases

Armillaria Root Rot

Also “oak root fungus”, “shoestring rot”, and "mushroom rot"

All stone-fruit rootstocks are susceptible to Armillaria root rot, which smells distinctly like mushrooms and occurs on the upper roots and/or crown of the tree. This destructive fungus lives within dead and living roots is transferred from root system to root system. It can live for up to 30 years.

Symptoms: Roots infected with Armillaria mellea have whitish-yellow fan-shaped mats between the bark and the wood. The tree trunk is girdled. Dull, yellowed, or wilted foliage is usually the first sign of trouble; infected trees usually die slowly.

Control: Manual
Exposing an infected crown and upper root area of a cherry tree may help to slow its growth into the crown. In spring, remove soil from around the base of the tree to a depth of 9 to 12 inches. Leave the trunk exposed for the remainder of the growing season. During the spring, summer, and fall, keep the upper roots and crown area as dry as possible. Recheck the hole every few years to make sure it has not filled in with leaves, soil, and other matter; the hole must be kept open and the crown and upper roots exposed.

Botrytis Rot

Damage commonly occurs to stone fruit and their blossoms during a wet, cool season. It appears on ripening fruit as brown spots and becomes covered with light brown spores.

Symptoms: Appears similar to brown rot (below). Fungus will overwinter in the soil and in plant debris.

Control: Spray

• Hi-Yield® Captan 50W Fungicide
• Monterey Fruit Tree Spray Plus
• Ferti-lome® Broad Spectrum Landscape & Garden Fungicide

Control: Natural Spray

• Natural Guard® Neem
• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil

Brown Rot

Includes: mummy rot and twig and blossom blight

Brown rot is a fungal disease that commonly affects stone-fruit trees, including cherry trees, especially after a long, warm, wet spring. It is one of the most common cherry-tree diseases. It affects the fruit tree’s flowers and fruit crop, but is not fatal. Fortunately, brown rot is easy to spot, prevent, and treat.

Symptoms: Blossoms turn brown and wither, but stay on the tree. Small sunken spots may appear at the base of infected blossoms, in the twig itself. Gummy brown “sap” may seep from these sunken areas. Leaves at the twig ends appear shriveled. Furry gray or beige mold forms on affected blossoms or twigs. The fungus rapidly spreads to the fruit.

Control: Manual
Plant a resistant variety, like Stark® Gold™ Sweet Cherry in a well-drained location. Prune regularly to keep trees open to light and air circulation, and remove any pruning debris, damaged or diseased fruit and limbs, as well as fallen fruit to avoid sites for fungi to thrive (do not compost). Thin fruit to avoid good fruit touching infected fruit. Disinfect your pruners between cuts to avoid spreading the fungi.

Control: Spray

• Hi-Yield® Captan 50W Fungicide
• Monterey Fruit Tree Spray Plus
• Ferti-lome® Broad Spectrum Landscape & Garden Fungicide

Control: Natural Spray

• Monterey Fruit Tree Spray Plus
• Ferti-lome® Triple Action
• Monterey Liquid Copper Fungicide

Spray preventatively if brown rot is problematic in your area, even before symptoms appear.

Buckskin (X-disease)

Buckskin disease is spread by some leafhopper species and is managed by planting disease-free stock, controlling weeds that host leafhoppers and removing leafhopper vectors and all diseased trees.

Symptoms: Diseased trees produce leathery, bumpy fruit that is pale in color, even at harvest-time. On Mahaleb rootstocks, trees rarely have fruit issues, but will suddenly droop above the graft union. Buckskin disease (also called “X-disease”) is caused by a phytoplasma organism in the cells of infected trees. Trees are usually infected in summer and fall, but will not show symptoms until the following year.

Control: Manual
Prune off infected twigs and limbs where cankers have affected the branch.

Cut out cankers that are less than half the branch circumference. Use a small, sharp knife and score the wood all the way around the canker, about an inch away from it. Dig the tip of the knife into the wood and bark as you work, and maintain a 1-inch margin around the circumference of the canker.

Slip the knife under the bark and remove the diseased inner bark, which is usually a rusty brown color. Round the edges of each incision to promote rapid healing, but do not remove the wood from the uninfected area below the canker.

Clean up any wood chips or debris and either burn it or dispose of it in the trash. Do not compost infected debris. Bleach the knife used to excise the canker, rinse and pat dry.

Apply fungicide spray to small wounds during wet periods and during dormant periods.

Canker (bacterial and cytospora)

Cytospora canker is caused by the fungus Cytospora spp. and attacks trees via weak or injured bark. Bacterial canker is caused by Pseudomonas syringae. Both tend to occur during cool, wet weather. They act and are treated similarly.

Symptoms: Infection appears as yellow-orange and black regions that later ooze a gummy substance which may have a foul odor. Cankers eventually develop in the branches, encompassing the circumference of the wood until it dies.

Control: Manual

Prune off infected twigs and limbs where cankers have affected the branch.

Cut out cankers that are less than half the branch circumference. Use a small, sharp knife and score the wood all the way around the canker, about an inch away from it. Dig the tip of the knife into the wood and bark as you work, and maintain a 1-inch margin around the circumference of the canker.

Slip the knife under the bark and remove the diseased inner bark, which is usually a rusty brown color. Round the edges of each incision to promote rapid healing, but do not remove the wood from the uninfected area below the canker.

Clean up any wood chips or debris and either burn it or dispose of it in the trash. Do not compost infected debris. Bleach the knife used to excise the canker, rinse and pat dry.

Apply fungicide spray to small wounds during wet periods and during dormant periods.

Control: Spray

• Ferti-lome® Broad Spectrum Landscape & Garden Fungicide

Control: Natural Spray

• Monterey Liquid Copper Fungicide
• Natural Guard® Caterpillar Killer Spray w/BT
• Monterey Horticultural Oil

Crown Gall

Caused by Agrobacterium tumefaciens — a bacterium that inhabits the soil and causes rapid, abnormal growth (developing into galls). Can spread through injury to roots in the soil as well as through gardening tools carrying the bacterium.

Symptoms: Trees appear stunted and slow growing; leaves may be reduced in size. In mature, fruit-bearing aged trees, may see little or no fruit. Woody, tumor-like growths called galls appear, especially at the crown (ground level) and below. Growths can restrict water and nutrient flow, but often the damage isn’t extensive enough to cause immediate or total death. If tree has died, inspect roots for hard, woody ‘tumors’ to identify Crown Gall as the cause. Note: Crown Gall is not the only thing that can cause stunted trees.

Control: Prevention

• Purchase gall-free nursery stock. Crown gall symptoms are generally well developed on finished nursery stock, making inspection a useful prevention strategy.

Additional Resources

• Contact local county Cooperative Extension agent for further advice

Phytophthora Root Rot and Crown Rot

Soil pathogens in the genus Phytophthora can cause crown and root rot diseases of almost all fruit and nut trees, as well as most ornamental trees and shrubs. This disease appears if the soil around the base of the tree remains wet for prolonged periods, or when the tree is planted too deeply.

Symptoms: Infected trees often wilt and die quick as soon as the weather warms up. Leaves may turn dull green, yellow, or even red or purplish. Symptoms may develop first on one branch then spread to the rest of the tree. Dark areas appear in the bark around the crown and upper roots. Gummy sap may ooze from the diseased trunk. Reddish-brown areas may show between the bark and wood.

Control: Manual
Good water management/drainage is the key to prevention. Never cover the graft union with soil and try to avoid direct watering of the crown. If you suspect crown rot, carefully cut away affected bark at the soil line. Trees can sometimes be saved by removing soil from the base of the tree down to the upper roots and allowing the crown tissue to dry out.

Control: Spray

• Ferti-lome® Broad Spectrum Landscape & Garden Fungicide

Powdery Mildew

Caused by Podosphaera leucotricha — a fungus that overwinters in buds and emerges during humid, warm weather progressively throughout the growing season.

Symptoms: Whitish-gray powdery mold or felt-like patches on buds, young leaves, and twigs. Leaves may crinkle and curl upward. New shoots are stunted.

Control: Spray

• Ferti-lome® Broad Spectrum Landscape & Garden Fungicide

Control: Natural Spray

• Ferti-lome® Triple Action
• Natural Guard® Neem
• Monterey Liquid Copper Fungicide
• Monterey Fruit Tree Spray Plus
• Monterey Horticultural Oil

Other Cherry Tree Issues

No Blossoms or Fruit

Sweet cherry trees take about 4 to 7 years after planting (on average) before they bloom or bear fruit. Pie/Sour/Tart cherry trees bear a little sooner, within 3 to 5 years after planting. If enough time has been allowed to pass, and the cherry tree is otherwise healthy, there are a few things to do to help it become fruitful.

• Make sure a pollinator variety is present. Most cherry trees require another different variety of cherry tree to be fruitful. Note: Sweet cherry trees and Pie/Sour/Tart cherry trees are not reliable pollinator for one another.
• Make sure your cherry tree variety is recommended for your zone. Low winter temperatures can injure sensitive fruit buds and blossoms, hindering fruit production.
• Space trees far enough apart to help avoid nutrient or light competition. Adequate space encourages a healthy and productive tree. Spacing can be estimated by the mature spread of the tree.
• Prune to help keep the fruiting wood and vegetative wood in balance so that there isn’t too much leaf development in lieu of blossom development in mature trees — or too much fruit-bud development and not enough leaves to “feed” the fruit.
• Know your soil. Soil conditions, and the presence of necessary nutrients, help keep a cherry tree’s roots supplying nutrients through its vascular system. If the soil is poor, or poorly drained, this affects the health and viability of the tree as a whole. If the tree is being over-fertilized, especially with a fertilizer high in nitrogen, it may develop lush, vegetative growth (leaves and branches) instead of developing fruit buds or blooming.

Additional Resources:

• Solving Fruit Tree Blooming & Bearing Problems

Sunscald and Sunburn (Scorching)

Sunscald/sunburn occurs during hot, dry growing seasons — with or without humidity in the air, but most commonly when humidity is low. Sunscald is also called winter injury or “southwest injury” as it commonly affects the southwest side of tree trunks during winter. Brown, crispy edges appear on leaves. Warm, clear days cause bark to expand and nights that are several degrees cooler will cause the bark to contract, damaging cells and causing splits and cracks in the trunk.

• Protect trunks prior to winter with tree guards or a diluted solution of water and white latex paint (50/50).
• Water new trees every 7 to 10 days during the growing season (if there is no rain within the week), or as needed (as the soil becomes dry to the touch).
• During the growing season, consider constructing a temporary shade cloth to protect trees from the sun on hot, dry days. Water as needed (see above).

Additional Resources:

• Winter Protection for Fruit Trees
• Drought Issues & How to Protect Your Trees

Water Stress

Can be caused by both overwatering and underwatering. Overwatering commonly presents as pale green to yellow leaves and leaf drop, which can weaken a tree, lead to root rot, and ultimately kill the tree. Underwatering often presents as discolored (usually yellowed), dry leaves. Tree may appear to wilt overall. Prolonged lack of water can kill the tree.

• Water new trees every 7 to 10 days during the growing season (if there is no rain within the week) or as needed (as the soil becomes dry to the touch).
• If planted in a location where the soil does not adequately drain water after heavy rains (leading to standing water), relocate the tree as soon as possible.
• If drought-like conditions persist, consider slow-trickle drip irrigation to allow water to reach the roots rather than wash over soil surface.

Additional Resources:

• Plan Ahead for Rainy Weather

Wind Injury

Symptoms: Can involve injury such as leaning/uprooted trees, breaks, tears, or wind-burned foliage. Depending on the severity of the injury, a cherry tree can either bounce back from minor damage or succumb to the wind-caused harm. This is determined on an individual basis and the health of the tree before the damage occurred.

Control: Manual

• Adequately tamp soil around the tree’s roots (and thoroughly water) at planting time to remove air pockets and ensure good contact with the soil. Air pockets and loose soil around the roots can cause the tree to rock easily, leaving it vulnerable to leaning or uprooting.
• Use tree stakes for new trees, dwarf trees, and trees planted in high-wind areas to help support upright growth and avoid leaning, uprooting, and breaking.
• Selectively thin fruit that may be weighing down limbs to reduce stress from the weight, and avoid tears or breaks during gusty weather. Be aware: pests and disease may also take advantage of resulting broken or torn areas if damage occurs.

If tender new foliage is blown or whipped around by the wind, it may appear discolored (dark — like a burn or bruise). Damaged leaves can be removed to encourage healthy, new growth.