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Fruit Trees Diseases

By Charmayne Smith ; Updated September 21, 2017

Fruit trees are deciduous, sun-loving trees that come in a wide variety of species. Whether grown as a backyard addition or within an orchard, fruit trees can produce for many years with the proper care. Still, even healthy trees can be susceptible to fruit tree diseases, many of which can be fatally detrimental if left untreated.

Powdery Mildew

Powdery mildew is a fungal disease that is spread by fungal spores. These fungal spores lie dormant through winter and become active in the spring. As the spores infect the foliage of the tree, the leaves begin to show small spots, covered with a powdery white dust. If left untreated, this disease can cause leaf distortion and drop, growth stunt and internal tissue death. Powdery mildew is easily treated, in its early stages, by removing debris around the area and treating with a fungicidal spray. It is a fungal disease that is common amongst most fruit trees.

Fire Blight

Fire blight is a bacterial disease commonly found amongst pome fruit trees, such as apples and pears. The disease causes symptoms as early as spring, infecting flowers and buds first. Initial symptoms include bacterial ooze from branches and twigs, wilted or blackened flowers and scorched shoots. Other symptoms include reddish-orange streaks in the bark, trunk cankers and deadened tissue. Treatment of fire blight includes an aggressive combination of pruning and chemical control.

Verticillium Wilt

Verticillium wilt is a soil-borne fungal disease that attacks trees through the root system. The disease is common among stone fruit trees, such as peach and cherry, and especially in those under distress and poor health conditions. Infected trees show symptoms that are also common with other diseases, including curling and wilting of leaves, discoloration of foliage and dieback. Removing and destroying the infected tree is the only proven control of verticillium wilt. An infected tree should be kept vigorous with a healthy schedule of irrigation and fertilization.

Brown Rot

Brown rot is a fungal disease that infects the blooms, fruit, branches and twigs of the tree. It is a major disease that is common among stone fruit trees. If untreated, the disease will cause a spread amongst the surrounding trees and eventual death. Infected trees show signs that include twig blight, rotting of fruit, lesions and cankers. The tree will also drop its leaves, twigs and branches very early. Controlling brown rot involves removing the infected areas from the tree. Remove surrounding tree debris from around the tree and properly destroy the debris. Also apply fungicidal treatment. The number of annual applications is dependent upon the type of fruit tree and severity of infection.

Alternaria Brown Spot

Alternaria brown spot is a fungal disease that is common in most citrus fruit trees. The disease attacks the twigs, foliage and fruit of the tree, causing lesions with yellowish colored circles. Attacking the veins of the tree, the fungal toxins eventually destroy the internal tissue of the tree. Along with brownish-yellow lesions, symptoms of alternaria brown spot include leaf and branch drop, defoliation and growth stunt. Fungicidal treatments and avid pruning of deadened areas assist in controlling the disease.

 

About the Author

 

Writing professionally since 2004, Charmayne Smith focuses on corporate materials such as training manuals, business plans, grant applications and technical manuals. Smith's articles have appeared in the "Houston Chronicle" and on various websites, drawing on her extensive experience in corporate management and property/casualty insurance.