21 Common Fruit Tree Diseases & How to Fix Them

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Fruit trees are a valuable addition to any garden or orchard, but they are highly susceptible to fruit tree diseases that can damage their leaves, fruits, and overall health. From apple scab to peach leaf curl, these infections not only reduce yields but also weaken the tree over time.

If left untreated, common fruit tree infections can spread rapidly, affecting nearby trees and leading to long-term damage. Understanding how to identify and treat common fruit tree diseases is crucial for maintaining a thriving orchard.

I once planted a peach tree in my backyard, eagerly waiting for juicy summer harvests. But as spring arrived, I noticed its leaves curling and turning red. A quick search led me to peach leaf curl, a fungal disease that could ruin my entire crop. With the right fungicide and proper pruning, I managed to save my tree. This experience taught me that fruit tree disease prevention starts with early detection and quick action.

Table of Contents

1. Apple Scab on Leaves and Fruits

Apple scab is a fungal disease that affects apple trees, causing dark, scaly lesions on the fruit and olive-green spots on the leaves. Infected apples often become misshapen and crack as they grow. The disease thrives in wet, humid conditions, spreading rapidly in orchards during the growing season. If left untreated, it can significantly reduce fruit quality and make apples unmarketable.

Remove and destroy infected leaves in the fall to prevent fungal spores from overwintering.
Apply fungicides containing sulfur or copper before bud break in early spring.
Choose resistant apple tree varieties like Liberty, Enterprise, or GoldRush.

2. Fire Blight on Pear Blossoms and Twigs

Fire blight is a bacterial disease that gives pear and apple trees a scorched, blackened appearance. It typically affects young shoots, blossoms, and twigs, causing them to wilt as if burned. The bacteria spread through rain, insects, and pruning tools, making it a fast-moving infection. Affected trees can die back rapidly if the infection reaches the main trunk.

Prune infected branches at least 12 inches below the affected area and sterilize tools between cuts.
Avoid excessive nitrogen fertilization, which encourages weak, fast-growing shoots that are more susceptible.
Spray trees with a copper-based bactericide during bloom to reduce infection risk.

3. Citrus Greening on Oranges and Leaves

Also known as Huanglongbing (HLB), citrus greening is a devastating bacterial disease that affects orange, lemon, and lime trees. Infected fruits are small, bitter, and lopsided, while leaves develop a characteristic yellow mottling pattern. The disease is spread by the Asian citrus psyllid, a tiny insect that carries the bacteria from tree to tree. There is no cure, making early detection crucial.

Remove and destroy infected trees to prevent the spread to healthy citrus plants.
Control psyllid populations with insecticidal sprays or beneficial predators like ladybugs.
Plant citrus varieties that show tolerance to the disease, such as Sugar Belle mandarins.

4. Peach Leaf Curl with Distorted Red Leaves

Peach leaf curl is one of the most recognizable stone fruit tree diseases, causing thickened, curled, and reddish-purple leaves in early spring. The fungal spores survive on tree bark and reinfect leaves every year if untreated. Severe infections can reduce fruit production and weaken the tree over time.

Apply a copper-based fungicide in late fall and again before bud break in early spring.
Remove infected leaves and dispose of them away from the orchard.
Choose resistant peach varieties like Frost, Redhaven, or Indian Free.

5. Powdery Mildew on Grape Vines

Powdery mildew is a common fungal infection that coats grape leaves, vines, and fruit in a white, powdery layer. It thrives in warm, dry conditions and can cause grapes to shrivel, reducing their sweetness and quality. If left unchecked, the disease can spread to other fruit trees, affecting apples, peaches, and cherries.

Improve air circulation by pruning excess foliage and spacing vines properly.
Spray with organic fungicides like neem oil, sulfur, or potassium bicarbonate.
Plant mildew-resistant grape varieties such as Chambourcin or Regent.

6. Brown Rot on Peaches and Nectarines

Brown rot is a fast-spreading fungal disease that affects stone fruits like peaches, cherries, and plums. Infected fruits develop soft, brown spots covered in fuzzy mold. The fungus can also cause twig blight and blossom infections, reducing overall fruit yield. Warm, humid weather increases the risk of outbreaks.

Remove and destroy infected fruit immediately to prevent spores from spreading.
Apply fungicides before flowering and during fruit development.
Ensure good air circulation by pruning branches and thinning fruit clusters.

7. Cherry Blossom Blight in Early Spring

Cherry trees are particularly vulnerable to blossom blight, a fungal disease that causes flowers to turn brown and wither before setting fruit. The infected blossoms remain attached to the tree, creating an unsightly appearance. Moist, rainy weather during the blooming season increases the risk of infection.

Apply fungicides before bloom and again when flowers begin to open.
Remove dead flowers and twigs to reduce fungal spores in the orchard.
Avoid overhead watering, which can spread the infection.

8. Black Knot on Cherry and Plum Branches

Black knot is a fungal disease that forms hard, black swellings along the branches of cherry and plum trees. The galls start as small, olive-green growths but darken and expand over time. If left untreated, they can girdle branches, cutting off water supply and causing dieback.

Prune infected branches at least 6 inches below the knot and burn them.
Apply fungicides containing lime sulfur in early spring.
Remove nearby wild cherry trees, which can harbor the fungus.

9. Bacterial Spot on Peach and Apricot Leaves

This bacterial disease causes peach and apricot trees to develop small, dark lesions on their leaves. As the infection progresses, the spots fall out, leaving a “shot hole” appearance. Infected fruits may have rough, scabby patches, making them unattractive for sale or consumption.

Plant resistant cultivars like Harrow Beauty or Contender peaches.
Avoid wetting leaves when watering to reduce bacterial spread.
Use copper-based sprays in early spring and after fruit set.

10. Cedar-Apple Rust on Apple Leaves

Cedar-apple rust is a fungal disease that affects apple trees, creating bright orange spots on leaves and fruit. It requires both apple and cedar trees to complete its life cycle, spreading spores between the two hosts. The fungal growths on cedar trees resemble orange, gelatinous blobs in the spring.

Remove nearby cedar trees if possible to break the disease cycle.
Spray fungicides like myclobutanil or sulfur before infection occurs.
Choose resistant apple varieties such as Liberty, Redfree, or Williams’ Pride.

11. Anthracnose on Avocado and Mango Trees

Anthracnose is a fungal disease that affects avocado, mango, and other tropical fruit trees, causing large, sunken lesions on fruit and dark patches on leaves. The disease thrives in humid conditions and spreads rapidly during heavy rains. If left untreated, anthracnose can cause premature fruit drop and lower fruit quality.

Prune affected branches and remove fallen leaves to reduce fungal spores.
Apply copper-based fungicides after flowering and during fruit development.
Improve air circulation by spacing trees properly and thinning out dense foliage.

12. Mosaic Virus on Citrus and Papaya Leaves

Mosaic virus causes citrus and papaya trees to develop irregular yellow-green patterns on their leaves. Infected leaves may become slightly curled or deformed, leading to poor fruit production. The virus is spread by aphids and infected plant material, making prevention crucial.

Control aphid populations using insecticidal soaps or neem oil.
Remove and destroy infected plants to prevent further spread.
Use virus-resistant varieties when planting new trees.

13. Shot Hole Disease on Cherry and Plum Leaves

Shot hole disease creates small, circular holes in cherry and plum tree leaves, giving them a characteristic “shotgun blast” appearance. The disease is caused by fungal or bacterial infections and can weaken the tree if severe. Infected fruit may develop rough, scabby patches.

Rake and dispose of fallen leaves to reduce disease spread.
Apply copper-based sprays before bud break and after petal fall.
Avoid overhead irrigation to prevent moisture buildup on leaves.

14. Crown Gall on Apple and Pear Trees

Crown gall is a bacterial disease that causes large, tumor-like growths at the base of apple and pear trees. These galls interfere with water and nutrient uptake, leading to stunted growth and reduced fruit production. The bacteria enter through wounds in the bark, making young trees especially vulnerable.

Avoid injuring the tree during planting or pruning to prevent infection.
Remove and destroy severely infected trees to stop the bacteria from spreading.
Use crown gall-resistant rootstocks when planting new trees.

15. Citrus Canker on Lemon Leaves and Fruits

Citrus canker is a bacterial disease that affects lemon, lime, and orange trees, causing raised, brown lesions with water-soaked edges on leaves and fruit. The disease spreads through rain, wind, and contaminated tools, making it difficult to control in citrus orchards.

Prune and destroy infected branches to reduce bacterial spread.
Disinfect pruning tools with a bleach solution after each use.
Apply copper-based sprays during the growing season to protect healthy foliage.

16. Verticillium Wilt on Almond and Fig Trees

Verticillium wilt is a soil-borne fungal disease that causes sudden wilting and yellowing on one side of almond and fig trees. The disease clogs the tree’s water-conducting tissues, leading to branch dieback and reduced fruit yield. It persists in the soil for years, making crop rotation ineffective.

Remove and destroy infected branches to slow disease progression.
Improve soil drainage and avoid overwatering to reduce fungal growth.
Plant resistant rootstocks to minimize susceptibility.

17. Peach Scab on Ripening Fruit

Peach scab is a fungal infection that causes small, dark, rough scabs to form on ripening peaches, often near the stem. While the disease does not penetrate deep into the fruit, it affects appearance and market value. It spreads through rain and wind, worsening in humid conditions.

Prune trees to improve air circulation and reduce moisture buildup.
Apply sulfur-based fungicides after petal fall and during fruit development.
Avoid wetting fruit when watering to prevent fungal growth.

18. Rust Disease on Coffee and Pear Trees

Rust disease affects coffee, pear, and other fruit trees, causing reddish-orange pustules on the undersides of leaves. Severe infections lead to premature leaf drop, reducing photosynthesis and weakening the tree. The disease spreads through airborne fungal spores, making prevention essential.

Remove infected leaves and dispose of them away from the orchard.
Apply fungicides like myclobutanil or sulfur at the first sign of infection.
Space trees properly to improve air circulation and reduce humidity.

19. Fusarium Wilt on Banana Trees

Fusarium wilt is a deadly fungal disease that affects banana trees, causing yellowing leaves and internal browning of the stem. The fungus blocks water uptake, leading to rapid wilting and plant death. It spreads through contaminated soil, making eradication difficult once established.

Plant disease-resistant banana varieties such as Cavendish clones.
Avoid planting bananas in infected soil, as the fungus can persist for decades.
Improve soil drainage to prevent fungal buildup in wet conditions.

20. Sooty Mold on Mango and Citrus Trees

Sooty mold is a fungal growth that covers mango and citrus tree leaves in a black, powdery layer. While not directly harmful to the tree, it blocks sunlight, reducing photosynthesis and fruit production. The mold grows on honeydew excreted by aphids, scale insects, and whiteflies.

Control sap-sucking insects with insecticidal sprays or natural predators.
Wash affected leaves with a mild soap solution to remove mold buildup.
Prune heavily infested branches to improve air circulation.

21. Apple Maggot Damage on Apples

The apple maggot is a small fly whose larvae tunnel into apples, leaving dark entry holes and winding trails under the skin. Infested apples become misshapen, with sunken, bruised areas where maggots have fed. The pests spread rapidly in unsprayed orchards, reducing fruit quality and marketability.

Use sticky red sphere traps to catch adult apple maggot flies before they lay eggs.
Remove and destroy infested apples to break the pest’s life cycle.
Apply kaolin clay sprays to create a protective barrier on fruit surfaces.