How to Control Pests and Diseases in Cherries: Causes, Symptoms, Chemical, and Biological Management

Botanically, the cherry fruit is a “Drupe” Cherry fruit belongs to many plants of the genus prunes and is packed with healthy nutrients and excellent antioxidants. There are two types of cherry fruit. Sweet cherries are great for eating raw and do best in bigger gardens. However, they cannot self-pollinate, so you must plant two or three trees to bear a harvest. As sour cherry trees self-pollinate and do not grow as large as sweet cherry trees, they are ideal for smaller spaces. The fruit of these trees is usually used for cooking.

How to Control Pests and Diseases in Cherries
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Cherries are cultivated all over the world nut native to Europe and Asia regions. India occupies as 26th producer on the list. Cherry fruit Cultivation requires cold conditions; northeast India is best suited for Cherry fruit cultivation. In India, due to the suitable climate, cherry commercial cultivation is carried out in the states of Himachal Pradesh, Jammu & Kashmir, and Uttar Pradesh. An annual rainfall of 100 to 125 cm is required for its growth. Several harmful diseases and pests affect these trees.

How to control pests and diseases in cherries

Diseases in cherry farming

Leaf spot/shot hole

When plants are stressed, the Cercospora leaf spot occurs on the leaves. The fungus can develop in seedbeds and after plants have been transplanted into bags. Shot hole disease attacks dormant leaf buds, blossom buds, leaves, fruit, and twigs (fruit infections are less common on cherries). Round holes are left by these infections when they fall out, giving this disease its name.

Disease symptoms
  • Small, round, purplish-black spots are the first visible lesions in young leaves.
  • Brown spots on leaves gradually expand with a reddish-brown margin.
  • Circular lesions can develop on fruit that appears first as reddish spots and then as rough, corky bumps.
  • Leaf drop is most common due to the disease being most severe on leaves.
Chemical control and management
  • Rake up and destroy infected leaves. Leaves may be composted if completely decayed before Spring.
  • Apply urea to leaves after leaf fall in autumn to enhance the decomposition of fallen leaves.
  • Treatments with organic fungicides include formulations containing copper salts such as copper hydroxide or copper sulfate may provide some protection against leaf spot infection.
  • The most common active ingredients to control cherry leaf spots include chlorothalonil, captan, strobilurins, and fungicides such as fenbuconazole, tebuconazole, and Myclobutanil. The alternation of active ingredients provides the best protection against the generation of resistant fungi.

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Cherries
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Bacterial gummosis

Gummosis refers to trees oozing sap profusely. Gumming is produced in response to various conditions, including insects, diseases, and wounding, and is most common on peaches, apricot, and sweet cherry. It can also respond to poor growing conditions, such as compacted soil. In addition, high humidity and warm temperature favor the development of disease.

Disease symptoms
  • Branches with amber-colored gum that exudes from flower buds, leaf buds, or pruning wounds
  • If the pathogen enters dormant buds in winter, they may be killed or open in Spring before collapsing in early summer; infected buds may not be symptomatic.
Chemical control and management
  • Sprays are available with fixed copper and a Bordeaux mixture that can be applied to the trees in the fall and Spring before bud break. However, some varieties are resistant to copper.
  • In the early to mid Spring, cankers can be controlled by cauterizing with a hand-help propane burner. Hold the flame over the canker for fifteen to twenty seconds until the bark and underlying tissue crackle and crinkle.
  • Apply captan, thiophanate-methyl, or lime sulfur (Bordeaux mixture) in 50% latex or kaolin clay to freshly cut pruning wounds. Do not apply copper hydroxide since this is toxic to the trees.
Silver leaf canker

The silver leaf fungus is caused by Chondrostereum purpureum. The disease is mainly spread by wounds that have been caused by pruning. Silvering of the leaves occurs during summer, and fruiting bodies form in late summer. The fungus produces toxins that affect leaves, killing entire trees or branches on some hosts. The diagnosis can be confirmed by cutting through a branch at least 2.5cm in diameter, moistening the cut surface, and checking for brown stains in the wood.

Disease symptoms
  • This fungus is named after the silver luster of some hosts’ leaves when it infects them
  • Die-back of the branches and twigs is the first sign of the disease. The affected leaves may later show brown spots in the middle and along the edges.
Chemical control and management
  • Providing enough water for a tree with a fungus will prevent water from moving through its branches. Provide water for a tree with a fungus, about 10 gallons for every inch of its diameter. This disease cannot be treated with fungicides.
  • Any branches showing leaf symptoms or conks should be pruned. Staining and conks on branches should be pruned at least 4 inches below where they are visible.
White root rot

Root rot in the apple is mainly caused by Dematophora necatrix Hartig, with its perfect stage as Rosellinia necatrix. This pathogen infects many hosts of about 158 species belonging to 45 different families, consisting of fruit and forest plants, herbs, Cereals, ornamentals, and other economically important plants. It is a disease that attacks the roots of trees growing in wet soil. Soggy conditions obstruct roots from absorbing all the oxygen they need. Even if the soggy conditions have been corrected, rot can spread from oxygen-starved roots to healthier roots.

Disease symptoms
  • Dematophora root rot is characterized by yellow foliage, shriveled fruit, and little or no new growth
  • Small feeder roots are covered with cottony, white mycelia, which causes the roots to decay.
  • As mycelia grow into the soil and upward in the tree, they form small, pale patches under or in the bark of major roots, the root crown, and the lower trunk.
  • As mycelium ages, it becomes gray or black. Young trees can also develop purple cankers at the root crown caused by this fungus.
  • Within 1 to 3 years of initial infection, diseased trees always defoliate and die prematurely.

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Cherry Tree
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Chemical control and management
  • Drench the soil under the tree canopy with Carbendazim 50WP (0.1%­) or Carbendazim + Mancozeb 75WP(0.5%) or Trifloxystrobin (25%) + Tebuconazole (50%) (0.08%). Or Metriam (55%) + Pyroclostrobin (5%) (0.2%) and fungicide suspension should be applied in 15-20cm deep holes made with the crowbar at a distance of 30cm throughout the tree basin.
  • Infested pits should be treated with Formaldehyde (3-5%) three weeks before the new plantation.
  • A moderately affected tree can sometimes be saved by pruning the infected roots and painting the ends with a disinfectant paste (Bordeaux). Always disinfect any tools you work with before using them again.
  • In the case of clayey soil, which encourages root rot, it should be amended by adding more well-decomposed organic matter.
Collar rot

Collar rot damages the rootstock just below the soil surface (crown rot) and causes necrosis and death of fine roots (root rot). While generally considered a larger problem in rain-fed growing regions with heavy soils, especially where irrigation water carries the pathogen or where irrigation and overhead cooling practices create wet soil conditions for extended periods.

Disease symptoms
  • Symptom expression depends on how many roots or crown tissues are affected and how quickly they are destroyed.
  • Generally, crown rots advance rapidly, and trees collapse and die soon after the first warm weather of Spring. Leaves of such trees wilt, dry, and remain attached to the tree. 
  • Chronic infections, usually of the roots, cause a reduction in growth, early senescence, and leaf fall.
  • These trees may be unthrifty for several years before succumbing to the disease. Phytophthora infections kill young trees because their root systems and crown areas are smaller than mature trees.
Chemical control and management
  • Applications of mefenoxam are made in early Spring and fall. Do not apply to trees within 45 days of planting.
  • For use as a foliar or soil treatment, use phosphorous acid.
Powdery mildew

Podosphaera clandestina, an obligate biotrophic fungus, causes powdery mildew on sweet and sour cherries. A white fungal growth occurs on the surface of mid and late-season sweet cherry cultivars (Prunus avium), rendering them unmarketable. Therefore, it is essential to control disease throughout the growing season for leaves and fruit in the orchard to minimize overall disease pressure and protect developing fruit from spore accumulation.

Disease symptoms
  • Light-colored circular lesions on leaves inside the tree canopy develop a powdery appearance; lesions may coalesce to cover the leaf.
  • If the infection is severe, leaves may blister, and infected shoots may be distorted and stunted; infected fruits may have slightly depressed areas on the surface containing.
Chemical control and management
  • Myclobutanil – Do not apply more than 3.25 lb product/acre per season. More effective when applied as a concentrate (80-100 gal/acre) than as a dilute spray.
  • Fenarimol – Apply treatment at late bloom to petal fall and repeat at 14–21 day intervals as required for control until harvest. Do not apply more than 1.4 L before harvest.
  • Tebuconazole – More effective when applied as a concentrate (80-100 gal/acre) rather than a dilute spray.
  • Wettable sulfur – Do not enter treated areas for 24 hours unless protective product clothing is worn. After applying oil, do not apply within three weeks. It may cause outbreaks of pest mites and may cause phytotoxicity.
Crown gall

The bacterial plant pathogen Agrobacterium tumefaciens cause crown gall. Crown gall bacteria infect plant roots through wounds. The wound may have been created by planting, grafting, soil insect feeding, excavation, or other physical damage. The condition and individual growth are called “gall,” and both cause cherry tree problems. Cherry tree crown galls are generally soft, not hard, and cause deformity or rot in the trees. Crown galls also appear on some 600 other species of trees.

Disease symptoms
  • On stems and roots, galls are tumor-like growths.
  • It is normal for new galls to be round, rough-textured, light-colored, smooth, and slightly spongy.
  • Older galls become hard and dry. Often they are dark in color, with many rough cracks and fissures.
  • It is common to find galls on the main stem where it enters the soil.
Chemical control and management
  • Trees and shrubs can be protected from crown gall infection by the biological control bacteria Agrobacterium radiobacter K-84.
  • Water roots of bare root plants or drenched potted plants with a solution of water and Agrobacterium radiobacter K-84 for biological control

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Cherry Farming
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Pests in Cherry farming

Pear psylla

Pear psylla Cacopsylla pyricola is one of the more problematic insect pests. Red-brown to black adult larvae are 4 mm long and larger than summer larvae. The wings are roof-like over the abdomen, like a miniature cicada. Hides under bark, litter on the orchard floor, or in sites outside the orchard. They feed by sucking the juice from their hosts. As soon as buds begin to swell, they start laying eggs. Eggs are deposited along the mid-veins and petioles of developing leaves and on stems and sepals of blossoms. Eggs hatch when foliage appears and continues throughout the growing season.

Damage symptoms
  • Water sprouts and new shoots are the primary sources of sap for nymphs and adults.
  • A large amount of honeydew is produced by nymphs, which makes the tree sticky and promotes sooty mold growth.
  • Fruits can be unmarketable if honeydew runs onto them, resulting in dark russet blotches or streaks.
Biological control
  • Predators: Lacewings, ladybird beetles, minute pirated bugs, predatory mites, anthocorid bugs, spiders
  • Washing honeydew off fruit trees with overhead sprinklers or airblast sprayers can significantly reduce fruit marking damage
Chemical control
  • Esfenvalerate – Esfenvalerate at low rates may no longer be effective where psyllas have developed tolerance to this material due to frequent use at higher rates. For dilute spray, apply 150–250 gal/acre. 
  • Abamectin – Most effective timing for this spray is at petal fall; it can be combined with a fire blight spray. Adults that survived the dormant spray have laid most of their eggs by this time. Therefore, this spray targets young nymphs as they hatch or feed.
Green peach aphid

Green peach aphid eggs are shiny, black, and about half the size of a pencil point. The eggs are only found on the bark of fruit trees. Aphid nymphs appear very similar to the un-winged adult, with yellowish-green pear-shaped bodies, black legs, and antennae. However, the body of the winged form is much slimmer with large, oval-shaped clear wings. The winged form may also have black markings on its body. 

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Cherry Trees
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Damage symptoms
  • Most species of plant-feeding thrips have piercing and rasping mouthparts.
  • The leaf’s surface develops a crinkled silvery appearance due to damage to cells below the surface.
  • Lightly-infested plants show silvery-feeding scars on the undersurface of leaves, especially alongside the midrib and veins.
  • Infested plants display silvering and browning of leaves, stunted young leaves, and scarred and deformed fruit.
  • The growing tips of developing leaves become distorted.
Biological control
  • Many common predators, including lacewings, lady beetles, and syrphid flies, attack the green peach aphid, 
  • And parasites, including the parasitic wasps Lysiphlebus testaceipes, Aphidius matricariae, Aphelinus semiflavus, and Diaeretiella rapae
  • You can control the green peach aphid with soap or horticultural oil since it is resistant to many insecticides, including pyrethroids.
Chemical control
  • Imidacloprid 200 SL (17.8% w/w)
  • Spirotetramat 11.01% + Imidacloprid 11.01% w/w SC
Thrips

A major pest of pome and stone fruit are tiny thrips (1-2mm), slender insects visible to the naked eye. A crop can be damaged during flowering (early season) or maturation (late season). The adults lay eggs in the growing parts of the plants, such as young leaves, flowers, or young fruits. A larva is usually found on a lower or older leaf, while an adult is usually found on a young leaf. Several generations can be produced in a year. Spring is the season with the most damage. In the colder region, the life cycle is longer with fewer generations.

Damage symptoms:
  • Most species of plant-feeding thrips have piercing and rasping mouthparts.
  • The leaf’s surface develops a crinkled silvery appearance due to damage to cells below the surface.
  • Lightly-infested plants show silvery feeding scars on the undersurface of leaves, especially alongside the midrib and veins.
  • Heavily-infested plants show silvering and browning of leaves, stunting of young leaves, and terminal growth, with fruit, scarred and deformed.
  • Developing leaves become distorted in the growing tips
Biological control
  • Parasitoids: Thripobius semiluteus
  • Predators: Predatory mites, predatory thrips, hoverflies, mirid bugs, Oligota spp., Orius spp., etc.

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Cherry Plant
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Chemical control
  • Apply Lime sulfur 22% SC at 0.8-2.0 l/acre
  • Use Captan 50% WP at 1 Kg in 300-400 l of water/acre
  • Alternatively, use Captan 75% WP at 0.67 Kg in 6-8 l of water/acre
Stem borer

Unlike other pests that feed on plant juices or foliage, cherry tree borers feed on the wood during their larval stage. During Spring, the larvae feed and construct tunnels deep into the wood. At the end of July, they prepare pupation cells protected by double plugs made from borings. Pupation occurs in these cells, and about two weeks later, adults appear. The adult has an elongated dark grey-brown body, 28–47 mm long, with elytra covered with short silvery hairs. Shiny silvery spots form two irregular bands crossing the elytra. 

Damage symptoms
  • Large emergence holes in trunks, branches, and borings at the basis of infested trees indicate the pest’s presence. 
  • The adult beetles are conspicuous and may be seen sitting on the trunks. 
  • Branch and tree die-back is easily detected by seeing wilting and drying leaves.
Biological control
  • As a preventive measure, pyrethrin-based bark sprays often work well. Leaves do not need to be sprayed, only the trunk and main limbs.
  • Spray neem seed kernel extract at 5%.
  • Damsel bugs, elm leaf beetle, some spiders, the big-eyed bug, parasitoid tachinid flies, or braconid wasps are all-natural enemies of the stem borer.
Chemical control

Treat the holes with the appropriate insecticide and seal holes with clay. Foliar spray with chlorpyrifos (0.05%) also helps reduce stem borer populations.

Conclusion

Early identifying insect pests and diseases can help you deal with them before they cause significant damage to fruit trees. When you know the signs, it is usually easy to identify the main culprits.

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