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Plant NameTypeDescription 
Armillaria root rotCherryDiseaseArmillaria root rot is a fungal disease often found in newly cleared soils or soils which have been flooded. Aboveground symptoms typically include production of smaller-than-normal leaves, leaf yellowing, premature leaf drop, and branch dieback, often on only a portion of the tree. White thread-like masses of the fungus may be found beneath the bark near the crown of infected trees, and/or as shoestring-like rhizomorphs, which are dark strands of the fungus growing on or just beneath the soil surface. Honey-colored mushrooms often grow near the base of infected trees in the fall. Infected trees may also exhibit a dark black line in the infected area encircling the base of the plant. Trees damaged by human activity such as construction or improper irrigation are more susceptible.
Bacterial cankerCherryDiseaseBacterial canker is favored by cool, wet weather and is common in western Washington. The bacteria overwinter in cankers, buds and other host tissues. Dark cankered areas on trunks and branches may develop and expand in early spring. The infected tissues may produce gum, although gumming can also be caused by other factors. The cankers often girdle twigs and branches, causing dieback above the lesion. Leaves on girdled twigs often yellow and fall by late summer. Infected buds may be killed or leaf infections may occur as the new growth emerges resulting in collapse of leaves. Infection can be spread by wind, rain, insects, pruning tools, or by planting or grafting with infected stock. The disease may spread throughout the entire tree (systemic infection) with or without visible symptoms.
Black knotCherryDiseaseBlack knot is a fungal disease that infects cherry and plum. Early infections of twigs are elongated olive-green, corky knots. They turn black and hard as they mature. Every year they expand lengthwise. It is possible for the fungus to stunt and kill limbs as it grows around the twig or branch.
Brown rot blossom blight and fruit rotCherryDiseaseBrown rot is a blossom-infecting fungal disease. Infected flowers wilt and die. The brown blossoms remain attached to the twigs, becoming covered with a grayish-brown fungal growth during wet weather. Blossom or fruit infections may spread to twigs. Infected twigs develop sunken, elongate cankers with gumming at the margins. Leaves on girdled shoots turn brown and remain attached. Infected fruit initially show a small brown spot which rapidly enlarges. The fruit remains fairly firm and often becomes covered with gray-brown fungus. Fruit may dry and harden into mummies, which serve as a source of infection in the spring.
Crown gallCherryDiseaseCrown gall is caused by a soilborne bacterium. The bacteria infect through wounds on the crown and roots. Young galls are fleshy, white, enlarged masses on the roots or stems. Older galls are hardened and turn dark brown and woody or corky in appearance. They range in size from less than an inch to several inches across. The bacteria may be transmitted on infected nursery stock. Water movement can spread the bacteria from infected to clean soil. Damage varies with location and size of galls. Small galls are essentially harmless. Large galls on the crown may weaken or girdle trees. The growths can also be an aesthetic concern.
Cytospora cankerCherryDiseaseThe fungi which cause Cytospora canker attack through wounds on twigs and branches. Initial cankers are small, but enlarge quickly and may streak up and down the stems without girdling. The cankers may also girdle twigs, resulting in dieback above the infection site and causing "flags" of dead material to appear in the canopy. The leaves on the dead twigs turn color and droop, but often remain attached. The canker itself appears as a dark, sunken area of dead bark and wood. Callus tissue forms around the margin of the canker. Amber gumming is often present. The pinhead-sized black fruiting structures of the fungi are rarely found on cherry. Spores are easily spread by wind, rain, and insects. The cankers are often perennial, enlarging through several seasons.
Dead budCherryDiseaseDead bud is a common symptom caused by the same bacterium which causes bacterial cankers. Initial symptoms are death of buds on lower branches of the affected trees. This begins in February prior to leafing out. Both leaf and flower buds are affected, and spurs may be killed back. Slight gumming may occur at the base of killed buds. Repeated loss of buds can cause trees to become misshapen and have a reduced fruit yield.
Gumming (Gummosis)CherryDiseaseGumming of cherry can be caused by several factors. It can be a physiological reaction to unfavorable growing conditions. Trees growing in damp conditions often produce gum, as do trees which have received excess water or nitrogen fertilizer (causing a sudden growth spurt). The gum often runs down branches or trunks, or may collect in branch crotches. Injuries often induce gumming, as well. Sunscald and mechanical injuries can be at fault. Gumming is also associated with cankers caused by diseases such as brown rot, bacterial canker, or Cytospora canker.
Leaf spotCherryDiseaseLeaf spot of cherry causes purple to reddish-brown spots on the leaves. The spots are up to 1/10" in diameter. In wet weather, the underside of the spots may produce cream-colored to pinkish masses of spores. Leaves may also turn yellow and drop soon after infection, or drop prematurely in the fall. This disease can result in minor to severe defoliation, which may affect fruit development. Spots sometimes occur on fruit stems, causing fruit to drop. Occasional infections occur on fruit. Mild, wet weather during the summer increases incidence of disease. The fungus overwinters in fallen diseased leaves. Sour cherries and sweet cherries grown west of the Cascades are more commonly infected.
Little cherryCherryDiseaseLittle cherry is caused by a virus transmitted by the apple mealybug and by grafting. Affected trees show symptoms primarily on the fruit, which may be smaller than normal, slow to ripen, and somewhat pointed or triangular. Dark-fruited varieties may not ripen past the bright red stage. Lighter varieties may have pinkish fruit. Affected fruit has a bland or rather bitter flavor. Foliage on affected trees may be lighter in color than normal trees, and growth may be somewhat reduced. Sweet, sour, and ornamental cherries may carry the little cherry virus. Fruit symptoms are mild on 'Deacon' and 'Royal Ann' sweet cherries, but severe on 'Lambert' and 'Black Republican'.
Mottle leafCherryDiseaseMottle leaf is a virus disease of cherries. Symptoms are seen mainly on the leaves, which are puckered and mottled with light green to yellow blotches between the veins. The mottling is less noticeable later in the growing season. Leaves may be smaller than normal and some shothole symptoms may occur. Shoots are rather stunted. Fruit produced on infected trees is generally small, slow in ripening, and of poor flavor. The cherry mottle leaf virus can be transmitted by budding or grafting, and by an eriophyid mite which is uncommon on sweet cherry. Bitter cherry (Prunus emarginata) is a common host of both virus and mites in the wild.
Necrotic rusty mottleCherryDiseaseNecrotic rusty mottle is believed to be caused by a virus. Affected trees are slower to leaf out and bloom in the spring. Terminal buds may be killed and the leaf and flower buds open irregularly. About a month after bloom, leaves begin to show angular purplish to brown spots. The spots may dry and drop out, giving leaves a tattered appearance. They can also coalesce and affect most of the leaf. Severely affected leaves develop a yellowish mottling along the veins and often drop. Defoliation can be severe. In the fall, remaining leaves turn mottled yellow and green, dropping prematurely. Decayed areas with gumming may be present on the bark. Twigs, larger branches, and whole trees may die. The necrotic rusty mottle virus is probably spread primarily by grafting with infected wood. 'Lambert' is severely affected, while 'Royal Ann' shows no symptoms.
Powdery mildewCherryDiseasePowdery mildew attacks leaves, young shoots, and fruit. This fungal disease initially produces a light green, circular spot on either leaf surface. Later, a characteristic white, powdery coating of the fungus appears, typically on the underside of affected leaves. The affected leaves may become blistered and distorted. Leaves on young shoots are affected first. The shoots may also become covered with the fungus. Diseased tissues are often deformed and stunted. Infected fruits develop round, depressed areas which may not show any fungal growth. Older infections may cover the entire fruit. The fungus can overwinter on the plant or in debris on the ground. Powdery mildew is favored by high humidity, warm days, and cool nights.
Prunus necrotic ringspotCherryDiseasePrunus necrotic ringspot is a viral disease affecting most cultivated Prunus species. Leaves may show various symptoms including brown, sunken, necrotic spots; chlorotic (yellowish to white) blotches or other patterns; or dark rings etched on the leaf. The necrotic spots may drop from the leaf, giving it a "shotholed" appearance. The disease is spread to healthy trees via infected pollen and by grafting.
Shothole (Coryneum blight)CherryDiseaseShothole is a fungal disease typically attacking leaves and fruit on cherry. Lesions on leaves are initially small, purplish, round to oval areas which expand into brown spots with light centers. The lesions are typically up to 1/4" in diameter. The infected spots on leaves often die and drop out in warm weather, giving leaves the characteristic "shothole" appearance of the disease. Fruit may develop one or more large brown spots which can involve large portions of the fruit. The fungus probably overwinters on the bark and in infected buds. Spores are easily spread by water and wind.
Verticillium wiltCherryDiseaseVerticillium wilt is caused by a soilborne fungus. It infects via the roots and then spreads throughout the plant. Aboveground symptoms include suddenly wilted yellow or brown foliage which hangs on the branches and dieback of twigs and branches. Symptoms of infection are often on only one side of the tree or scattered throughout the canopy, but may not be noticed until warm weather or other periods of stress. Disease symptoms usually first appear near the ground and progress upward. Affected branches typically show dark streaking in the xylem. Affected trees may die or gradually recover. Young trees are more seriously affected.
Witches'-broom (Cherry leaf curl)CherryDiseaseWitches'-broom disease of cherry is a fungal disease similar to peach leaf curl. Infected branches develop large, dense, broomlike tufts of foliage. These branches typically do not produce flowers or fruit, making them particularly conspicuous during bloom. The leaves are discolored (red to brown), thickened, and curled or puckered. Whitish fungal growth may be present on the underside of curled leaves. Diseased leaves occur both in witches'-brooms and on normal branches. Diseased branches do not recover.
Apple-and-thorn skeletonizerCherryInsectThe adult of the apple-and-thorn skeletonizer is a small dark-brown or reddish-brown moth. The skeletonizer overwinters as a pupa or an adult, with the females laying eggs in the spring. The caterpillars are yellow-green in color, have black spots and brown heads, and feed on the leaves of several plants including apple, crabapple, pear, and hawthorn. Caterpillars are about 1/2" long at maturity. Characteristic damage includes skeletonized leaves, or leaves that are rolled into a cone and tied with webbing. Damaged leaves are brown and papery and drop prematurely.
Black cherry aphidCherryInsectThe black cherry aphid is a shiny, black, pear-shaped insect. Sweet cherry is the preferred host. The soft-bodied aphids feed in colonies on the tips of new growth, causing curling and distortion of the shoots and leaves. Injured leaves may turn brown and die back. The aphids overwinter on cherry as eggs, then young aphids feed on buds and leaves in the spring. Winged adults migrate to plants in the mustard family, which are the summer hosts of the aphids. Feeding aphids produce large amounts of honeydew, a sweet, sticky substance which may attract ants or become covered with a dark growth of sooty mold. The sooty mold can reduce fruit quality.
Brown marmorated stink bugCherryInsectThe brown marmorated stink bug (BMSB) is an introduced pest species from Asia that is spreading quickly across the United States. Nymphs and adults feed on a wide variety of plant hosts. BMSB prefers to feed on fruit, seeds, and seed pods, but will also feed on stems and leaves of some hosts. Both adults and nymphs have piercing-sucking mouthparts and inject digestive enzymes into plant tissues to aid in feeding. Sunken areas and deformities (catfacing) on the surface of the fruit are typical symptoms. Damaged areas are discolored beneath the fruit’s skin and become hard and pithy or corky in texture. Stone fruits such as cherry, peach, plum, and apricot may show gumming at the injury site and from the corky areas beneath the surface. Other known tree fruit/nut hosts of BMSB include apple, pear, filbert, and stone fruits including apricot, peach, and plum. One or two generations of BMSB per year are expected in the Pacific Northwest. Adults overwinter in sheltered locations (including houses, where they can become a significant nuisance pest). In the spring, light green to white eggs are laid in groups of about 20 to 30 on the underside of leaves. Young stink bugs, or nymphs, are black with a red-and-black striped abdomen. Nymphs often feed in groups when young. Older nymphs are dark with white bands on body, legs, and antennae. They may feed in groups or singly. Adults are a little over 1/2 inch long, with a shield-shaped body. Body color on adults is mottled gray and brown, while the legs and antennae have alternating dark and light bands. The abdomen also has dark and light bands which are visible at the edge of the wings. NOTE: BMSB adults closely resemble other stink bugs found in WA and OR. For more information on BMSB identification, see FS079E, Pest Watch: Brown Marmorated Stink Bug, available at https://pubs.wsu.edu/.
Cherry bark tortrixCherryInsectThe cherry bark tortrix (CBT) is a pest of most woody ornamental trees and shrubs in the family Rosaceae. CBT attacks Prunus (cherry, plum and peach), Malus (apple, crabapple), Pyrus (pear), Crataegus (hawthorn), Sorbus (mountain ash), Cydonia (quince), Pyracantha (firethorn) and Photinia. CBT has one generation per year and a prolonged flight period from April until September. All life stages occur within the host tree except for the eggs and adults. Eggs are laid singly on the bark surface. Hatching larvae penetrate the bark through openings (natural and mechanical wounds) and feed on the living tissue of the tree's bark. Graft unions of ornamental trees are preferred sites for attack. Larvae do not penetrate the hard wood of the tree. During feeding, CBT larvae construct a frass tube consisting of fecal pellets and webbing. The frass tube is the location for pupation once CBT has completed the larval stage. Frass tubes are an excellent indication of CBT infestations and susceptible trees should be regularly monitored for frass tubes.
Cherry fruit flyCherryInsectCherry fruit fly adults are brown to black flies with white bands across the abdomen. The wings are clear with distinctive dark bands. The fly is about 1/5" long. Eggs are laid beneath the skin of cherry fruit. Larvae are tapered, cream-colored to white maggots up to 1/4" long. The larvae burrow and feed inside the cherries, destroying the fruit. The maggots leave the fruit via an exit hole to pupate in the soil, sometimes remaining dormant for up to two or three years. Adults emerge beginning around May.
Cutworms and armywormsCherryInsectCutworms are the larvae of noctuid moths. These common moths are medium-sized with fairly dull coloration. The gray to tan caterpillars are hairless, nocturnal, and generally spotted, striped, or otherwise marked. They may be 1/4" to 1" in length and tend to curl up when disturbed. Cutworms feed by chewing leaves and buds, typically on lower portions of the tree. Symptoms of damage include ragged, irregularly chewed leaf margins and buds damaged prior to bloom. Fruit may also be damaged, with small to large holes chewed into the surface. Cutworms typically spend the day just beneath the soil surface or under debris near the host. While armyworms are typically day feeders, cutworms usually feed at night. It is advisable to search for them with a flashlight in the dark. Weeds are the primary food source for cutworms.
EarwigsCherryInsectEarwigs are reddish-brown insects about 3/4" or less in length. Both males and females have pincers at the rear end. Earwigs are largely beneficial, feeding on many pests such as aphids, mites, and nematodes, as well as on algae, fungi, and decaying plant material. However, earwigs can also damage plants. They sometimes feed on flowers, shoot tips, leaves, or fruit. Damaged shoot tips may fail to develop properly, sometimes stunting growth. Damaged leaves exhibit small to large holes. Fruit damage typically consists of shallow, irregular areas chewed into the surface.
LeafrollersCherryInsectSeveral species of leafrollers may be found on cherries. The larvae feed on leaves, buds, or fruit. They vary in color from pale to dark green, usually have a shiny brown or black head, and are about 3/4" long at maturity. Typical symptoms of leafroller feeding include leaves that are rolled and tied in place with webbing. Damaged leaves are often near shoot tips and may be skeletonized or chewed. Shallow surface damage may be seen on the fruit, but damaged fruit often drop before harvest. Leafroller caterpillars are often active when disturbed, wiggling vigorously or dropping to the ground on a thread. The adult moths are 1/2" to 3/4" long and are brown or mottled tan and rusty brown. Some species have darker bands across the wings.
Peachtree borerCherryInsectThe peachtree borer adult is a dark, bluish, clear-winged moth which somewhat resembles a wasp or hornet. The female, which has dark forewings and a red-orange band on the abdomen, lays eggs on the tree. Emerging larvae move to ground level or just below ground, where they burrow beneath the bark on the trunk and feed in the crown region. Signs of larval feeding include the presence near ground level of jelly-like gum mixed with dirt and pellets of excrement. Heavy infestations can weaken older trees, and foliage may be yellowed as if nitrogen-deficient. Young trees may be girdled and killed.
Pear slug (Cherry slug)CherryInsectThe pear sawfly is also known as the pear slug or cherry slug because of its resemblance to a small, dark slug. These insects are the larval stage of a glossy black sawfly about 1/5" long. The larvae are covered with a dark green to black slime which gives them the slug-like appearance. The caterpillar-like larvae are yellow immediately after molting and until the slime is produced. Larvae are also yellow-orange immediately before pupating. Pear slugs feed on upper leaf surfaces, skeletonizing leaves. Severe infestations can cause defoliation, weaken trees, and affect fruit development. The pear slug prefers cherry and pear, but will also feed on plum.
San Jose scaleCherryInsectSan Jose scale is an armored (hard) scale found on many deciduous trees and shrubs including apple, cherry, elm, maple, poplar, and willow. The scale insects are about 1/16" in diameter. The female is gray with a yellow spot in the center. The yellow crawlers are easily spread by wind, birds, or people. San Jose scale may be found on twigs, branches, leaves, and fruit. Heavily infested branches or entire trees may wilt and appear water-stressed. Severe infestations can cause twigs and branches to die back. Repeated infestations can kill trees. Infested fruit develop sunken spots surrounded by reddish areas. The scale overwinters as black immature scales on bark.
Shothole borerCherryInsectShothole borers are small (1/10" or less), brown to black, stubby-nosed beetles. Adults feed at the base of leaves or twigs. Later, they bore into the bark and lay eggs along a narrow gallery paralleling the grain of the wood. The white, legless grubs (bark beetles) feed by boring between the bark and sapwood, making narrow tunnels filled with sawdust-like frass (excrement). Feeding larvae can weaken or girdle trees. Larval galleries are typically at right angles to the first gallery, with the grubs pupating at the end of the galleries. The emerging adults leave tiny round "shotholes" in the bark, giving the beetle its name. Shothole borers are especially attracted to injured, stressed, or dying trees, but can also attack healthy trees. Fruit, ornamental, and forest trees and shrubs are attacked.
Spider mitesCherryInsectSeveral species of spider mites can be found on cherry. They range in color from pale yellowish or green to red or brown. Spider mites feed on the leaves (typically on the underside), causing a whitish, yellow, or brown stippling. More severe damage results in leaves taking on a bronzed appearance. Heavy infestations may cause leaf drop. Spider mite feeding is usually accompanied by webbing on leaves and between leaves and twigs, although the European red mite produces smaller amounts of webbing than other species. Spider mite infestations are worse in hot, dry, dusty conditions.
Spotted wing Drosophila (SWD)CherryInsectSpotted wing Drosophila (SWD) resembles other Drosophila species (fruit flies or vinegar flies) in appearance, but unlike other members of the family which attack only overripe, damaged or decaying fruit, SWD attacks healthy fruit as it ripens on the plant. Adult SWD flies are about 1/8 inch long, with red eyes and a yellow-brown body. Darker bands may be visible on the abdomen. Male flies have a distinctive dark spot on the leading edge of the wing near the tip. SWD is the only fruit fly species in our area with this spotted wing, making identification of males relatively simple. Females lack the spotted wing, but have a large, sawlike egg-laying organ called an ovipositor at the tip of their abdomen. It is used to deposit eggs in fruit (oviposition). The eggs are laid beneath the surface of ripening fruit as it begins to soften and show color (from light straw color in sweet cherry), continuing through to harvest. Scars left by oviposition may appear as indented, soft spots on the fruit surface. Small white- or cream-colored larvae hatch within a few days and feed in the fruit, causing the fruit to soften and collapse around the feeding site. Further damage may be caused by secondary pathogens (fungi and bacteria) which attack the damaged fruit. At maturity, the larvae may be up to 1/8 inch long. They may pupate inside or outside the fruit. The length of the life cycle depends on temperature, with adults most active at cool temperatures (around 68 degrees F). Most soft-skinned fruits are vulnerable to attack by SWD, including peach, plum, cherry, grapes (table and wine), strawberry, blueberry, and cane fruits. It has also been found in Asian pear, fig, and hardy kiwi. See SWD under Common Insects for an additional image of the larval stage.