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Avocado Tree Diseases

Avocado Tree Diseases

Like other trees, the avocado tree is also susceptible to diseases. This article gives you an overview of the various kinds of diseases that affect this tree.
Hemangi Harankhedkar
The avocado tree is a tropical evergreen/sub evergreen tree, which is native to Central America and Mexico. The tree, if properly cultivated and cared for, can reach a height of up to 60 feet, but the normal height seen is around 30-40 feet. The fruit of the avocado tree―its most nutritious part,―is full of essential nutrients, dietary fiber, vitamins, potassium, and magnesium. It is a good source of mono-saturated fat, which is considered a healthy fat.

The avocado fruit is a regular in American households, and is a common ingredient in many recipes. An average-sized avocado tree generally produces 120 avocados annually. A subtropical and tropical climate with good sunlight is favorable for the smooth cultivation and growth of this tree.

Common Diseases

It is prone to diseases of various kinds which can hamper its growth. There are a number of causes, some of them being―improper irrigation, injury of some kind, environmental and soil conditions, and infections.

Powdery Mildew
Powdery mildew is basically a fungal disease which affects the leaves. It is characterized by the appearance of purplish and brownish spots on the lower side of the leaves, and greenish or yellowish spots on the upper side. In mild cases, this infection can be removed by rubbing the leaves. In severe cases, a powdery substance appears on the leaves. A fungicide is generally used to treat this disease.

Avocado Root Rot
This is a fungal disease which basically affects the roots of the avocado tree. The roots start getting brittle once they are affected. Eventually the twigs and stems begin to die, and the leaves fall off. This disease is characterized by the appearance of pale yellow leaves and low fruit production. It can be cured using a fungicide.

Pseudocercospora Spot
This is another disease that affects the avocado tree, especially in warm and humid weather. The fruits, stem, and leaves are commonly infected, and brown-black lesions appear on the infected leaves. It is treated by using azoxystrobin spray.

Anthracnose Fruit Rot
This is another fungal disease which affects the fruits, stems, and flowers of the tree. It is caused by a fungus called Colletotrichum gloeosporioides. Regular use of fungicides help in prevention of this disease which is characterized by the appearance of dark sunken spots on the avocado fruit, which rapidly spread to the surrounding tree structures.

Avocado Black Streak
This disease is characterized by the appearance of lesions and cankers, and affects the fruit production of the tree. It also causes yellowing of the leaves. It can be best prevented by using proper irrigation techniques and soil fumigation.

Avocado Sunblotch
This viral disease lowers the yield of the tree and also results in poor quality fruit. It is caused by a virus called ASBV (Avocado sunblotch viroid). This disease is serious and the virus can be passed to other trees as well.

List of Other Diseases

  • Anthracose
  • Armillaria root rot
  • Shoestring root rot
  • Black mildew
  • Butt rot
  • Branch canker
  • Cercospora spot
  • Collar rot
  • Dematophora root rot
  • Die back
  • Fruit rot
  • Leaf spots
  • Phomopsis spot
  • Phytosalospora crown rot
  • Pink rot
  • Root and bark rot
  • Rosellinia root rot
  • Scab
  • Seeding blight
  • Smudgy spot
  • Tar spot
  • Verticillium wilt
  • Wood rots
  • Bacterial canker
  • Blast and bacterial fruit spot
  • Crown gall
  • Sunblotch
  • Trunk pitting
  • Algal spot
  • Blackstreak
  • Dieback
  • Edema
  • Littleleaf rosette
  • Tipburn

Avocado trees are versatile in adaptation to different soil and environmental conditions, and grow best in full/partial sunlight. Select a place big in terms of area to grow them in order to avoid problems in the future. The roots of this tree are quite big and strong, and may pose a threat to the trees surrounding it. Do not water a young avocado plant frequently and fertilize it after the first year. Well-drained soil with pH of 6-7 is best suited for this tree.