Insect Pests of Cherry Trees
Listed below are some common pests of sour cherry trees in Ohio. They are Black Cherry Aphids, American Plum Borer, and the European Red Mite. Mature cherries are also attacked by the Peachtree Borer and the Shothole Borer. Scroll down for more information about the identification and management of these pests.
Black Cherry Aphid (Myzus cerasi)
Black cherry aphids are the only type of aphids that affect cherry trees. Cherry trees are its winter host. In the summer months the aphids will move to plants in the mustard family.
Black cherry aphids on leaf.
These insects are small, shiny metallic black, and soft-bodied. They are approximately 3mm in length and may or may not have wings depending on the population density. (Aphids at a very high population density will grow wings.) You will typically find these insects clustered on stems or on the underside of the tree’s leaves.
In sweet cherries, the affected leaves become stunted, twisted/curled, yellow and die. In tart varieties, however, this symptom does not seem to occur. The honeydew secreted by the aphids drips on the leaves, fruits, and the surrounding ground. This may attract ants tht can cause further damage to your tree.
Watch your tree(s) closely when buds are appearing in late winter/early spring. Yellow sticky cards placed on various parts of the tree will give you an idea of how severe the infestation is. For particularly stubborn infestations, early spring is the best time to spray black cherry aphids with horticultural oil, a natural substance that will kill the aphids as they hatch. Non-Chemical: Aphids are easier to manage before the leaves are curled, and you may be able to dislodge the pests with a strong stream of water. Biological control can be used to manage an infestation using the aphids’ natural enemies including certain species of lady beetles, lacewings, and several species of parasitic wasps.
American Plum Borer (Euzophera semifuneralis)
American plum borer damage to tree trunk (NYIPM)
The beginning larval stages of this pest are white with a large, brown head. Mature larvae are about 1 inch long, dusky white, pinkish or dull green in color. The forewings of the adult moth are gray with brown and black markings, with a wingspan of about 3/4 of an inch.
The larvae of this pest will bore into your tree, leaving reddish orange frass (insect “poop”), webbing, and gum pockets. The boring is most damaging to the scaffold crotches or graft unions of young trees. A thick, gummy substance (sap) will begin leaking from round holes found on the trunk or in the crotch of your tree.
Traps in the form of tanglefoot-coated logs or posts can lure adults, later to be removed from the site and burned.
Keep your cherry tree as healthy as possible with proper watering and fertilization, as American Plum Borers are notorious for attacking weakened or stressed trees.
European Red Mite (Panonychus ulmi)
European red mite stippling damage to leaf.
The female European red mite is about 0.02 inch long and has a brick-red globular body with long curved hairs that arise from white spots or tubercles on the back. Nymphs or unfed females may appear greenish. European red mite eggs are red, slightly flattened, and have a stipe (a stalk-like protrusion) protruding from the top.
European red mites remove the contents of the leaf cells as they feed, causing leaves to take on a finely mottled appearance. Rarely do European red mites cause leaf drop in cherry trees.
If overwintering eggs are present, applying a delayed dormant oil spray each year is the most important management tactic for the European red mite. Eggs are most vulnerable to control just before hatching. If a delayed dormant spray is missed, later sprays may be required to keep European red mite populations below damaging levels. Non-Chemical: The Western predatory mite (Typhlodromus occidentalis), will feed to some extent on immature stages. While the western predatory mite can sustain itself on European red mites, it cannot break the shell of European red mite eggs, thus it takes longer for this predator to bring a population of these mites under control.
Peachtree Borer (Synanthedon exitiosa)
Peachtree borer males look like small wasps!
The adults are clearwing moths that can look like blue-black wasps. They are rarely seen unless a pheromone trap is used. The larvae are creamy white caterpillars that usually burrow at the bases of cherry, peach and plum trees. This often causes the tree to exude sawdust-filled, brown sap.
Peachtree borer larvae are creamy-white with a brown head capsule.
The larval burrowing at the base of the tree interrupts the nutrient flow in the tree which can first show up as slow growth or premature drop of fruit and leaves. Repeated attacks will eventually girdle the tree, thereby killing it. Unfortunately, the damage is often hidden by mulch placed around the base of the tree.
Peachtree borer adults are attracted to tree wounds for egg laying, especially at the base of the trunk. Take care when mowing or weeding around trees so as to avoid damage to the bark. A time-honored method of control has been to physically dig out the larvae if sap flows are noted at the base of infested trees. Chemical control is difficult in backyard situations as agricultural chemicals may be needed. These are usually applied to protect the bases of trees as soon as adult males are captured in pheromone traps.
Keep the cherry tree as healthy as possible with proper watering and fertilization, and avoid any bark damage on the lower trunks of trees.
Shothole Borer (Scolytus rugulosus)
Shothole borer attacks first produce gummy sap flows from small holes!
This pest is also know as the fruit tree bark beetle. The tiny brown beetles burrow into weak or dying branches where globs of gummy sap exudes.
Symptoms of attach mean that the infested tree is under severe stress and should be looked at closely for other signs of disease, girdling or attack by the peachtree borer (at the base of the tree). Attacked branches will usually die, so they should be pruned out immediately.
There are few “remedies” for this pest once an attack has occurred. If the attack is only in a smaller branch, that branch should be prunded out and destroyed immediately. Unfortunately, when shothole borer attacks the main trunk of the tree, the whole tree is likely to die!
Keep your cherry tree as healthy as possible with proper watering and fertilization. Be especially watchful for the peachtree or American plum borers which can girdle entire trees.
Black Cherry Aphid – Washington State University Extension
How to Manage Cherry Pests – University of California IPM (compete group of factsheets on cherry pests)
American Plum Borer – University of California IPM
European Red Mite – University of California IPM
Peach Tree Borer – University of Kentucky Extension
The Midwestern Home Fruit Guide is a regional bulletin that covers all the fruits that a home gardener may wish to grow. It is a “for sale” bulletin, but well worth the $24!! Click on the title to go to a web page for ordering this guide. This bulletin covers cultural and chemical control of diseases and insects that attack fruits.
(We wish to thank Dr. Celeste Welty for consultations!)