Apple Diseases

Apple trees are grown throughout the U.S. Over many years of cultivation and control, apples have adapted to many climates, producing a variety of fruits, each one unique. Unfortunately, no matter how controlled the cultivating process, apple trees are susceptible to a variety of different diseases from fungus to bacteria. Proper identification and control measures can save a sick apple tree and prevent further outbreaks.

Fruit and Foliar Diseases

Fruit and foliar diseases are common. Apples that suffer fruit and foliar can lose their entire yield of apples in a season if left untreated. The most common characteristic of fruit and foliar disease is the appearance of lesions on the apple and leaves. Pesticides and proper upkeep of the orchard, such as the trimming of affected branches and the cleaning of fallen apples from from the base of the tree, can go a long way in preventing an outbreak. Blackrot and frogeye leaf spot are the most common of the fruit and foliar diseases.


Scab is a disease that occurs in the eastern part of the Eastern United States. Scab develops in cool, wet weather, and is identified by its olive-colored lesions, that appear on the underside of the leaves of the apple tree. Scab, since it is produced by a fungus, can be control through the use of fungicides. Fungicide should be applied once green tips appear on the tree until the petals of the tree begin to fall.

Black Rot

Black rot is common in trees that are poorly kept. The disease is caused by fungus spores that grow on apples which have dropped from the tree, or have been left on the branch and have become mummified over the winter months. Rain then moves the spores onto the buds of the newly forming fruit. The fungus remain dormant until the fruit appears, attacking the fruit for sustenance. Petal fall causes further infection throughout the tree. Black rot can be controlled through fungicide and the proper care and maintenance of the tree.

Keywords: apple diseases, unhealthy apple tree, black spots apple tree

About this Author

Cleveland Van Cecil is a freelancer writer specializing in technology. He has been a freelance writer for three years and has published extensively on, writing articles on subjects as diverse as boat motors and hydroponic gardening. Van Cecil has a Bachelor of Arts in liberal arts from Baldwin-Wallace College.