Apple Tree Diseases & How to Cure Them

A healthy apple tree is both more attractive and productive than a diseased one.

Apple trees fall ill to a variety of diseases that compromise the aesthetic quality of your landscape and the potential for fruit production. Attacked by a diverse group of pathogens including bacteria and fungi, apple trees need optimal care. Determining a cure is often a multifaceted project. Some diseases are avoidable only through preventive measures. Paying attention to the material you are planting as well as the appropriateness of your gardening space to that plant is essential in maintaining a healthy garden.

Things You'll Need

• Gardening gloves
• Protective eyewear
• Pruning shears
• Fungicide
• Bactericide

Instructions

1. Purchase disease-free rootstock and plant in healthy soil to prevent growing contaminated trees. Select plants from reliable, trusted sources.

2. Examine your trees for signs of disease like any abnormal changes in color or texture.

3. Look for spots on leaves and fruits that change colors or form depressions. Identify apple scab fungal disease by its symptoms of olive green spots as well as black growth on fruit. Recognize powdery mildew fungal disease by its white to gray powderlike growth on plant surfaces as well as leaves that appear warped or dwarfed.

4. Search for signs of a bacterial infection like fire blight on your apple trees. Examine flowers first, as this is where the disease typically begins, then examine the fruit, twigs and leaf shoots. Look for flowers that appear as though they are saturated with water that then wilt and brown. Search for blackened, dried fruit and similar problems on other plant parts like twigs, according to the North Carolina State University Integrated Pest Management.

5. Prune and destroy affected plant parts when fungal and bacterial diseases attack your apple trees to prevent further spread of infection as pathogens typically move from one plant to another on wind and water.

6. Determine the appropriate fungicide for fungal disease or bactericide for bacterial disease. Use fungicides with the active ingredient bordeaux or sulfur for apple scab, for example. Apply a fungicide with the active ingredient thiophanate-methyl or triadimefon for powdery mildew and choose chemicals with the active ingredient streptomycin or copper hydroxide for control of fire blight, according to the Clemson University Extension.

Tips & Warnings

• Contact your local extension agent or a licensed professional for assistance in verifying the disease in question. Avoid improperly attempting to cure your tree of the wrong disorder by consulting an expert. Discuss a potential control program tailored to your particular problem and gardening space.

• Maintain consistent care of your apple trees as vigorous plants are more likely to avoid and recover from diseases. Grow apple trees in full sunlight and well-drained soil.

• Wear gardening gloves and protective eyewear to prevent injury when handling sharp tools or chemicals.

References

• Clemson University Extension: Apple & Crabapple Diseases
• NC State University IPM North Carolina: Diseases of Apples
• North Carolina Cooperative Extension Service: Growing Apple Trees in the Home Garden