The splitting of apple tree bark is one of the most common issues in apple tree care. It is caused primarily by a few different factors, including environmental stress, insect pests and fungal and bacterial infection. A combination of these or any one of them can be the cause and understanding the reasons why allows for effective control and prevention.
Environmental Stress
Excessive exposure to sun, drought and cold temperatures can cause the protective bark of an apple tree to split and peel. This is especially the case with apple varieties that are not acclimated to the local environment. Trees can become more susceptible to bark splitting when conditions are already quite dry.
Insect Pests
Insects can cause “rameal cracking” or “bark split,” which involves crusty, discolored areas on the bark caused by injury. The types of insects that may cause this condition are larvae of scale, splitting mites, caterpillars and wood-boring beetles. Insects normally infest weaker or damaged apple trees.
Fungal Diseases
The fungus Nectria galligena affects apple tree bark, causing it to split. This fungal disease begins as raised bumps on the bark, which later ripen and become covered with pink spots. The bark then begins to crack and the fungus slowly spreads. The condition is often seen during the fall season.
Bacterial Infection
Apple tree bark can also be affected by bacterial infection. Bacteria like Pseudomonas syringae create wounds in the bark, leaving behind a darkened area as a sign of infection. These lesions become enlarged and eventually crack. The bacteria can spread to the entire tree when not controlled in the early stages.
Control: Protection Against Environmental Stress
To protect apple trees from environmental stress, adequate irrigation and mulching should be provided throughout the growing season. The soil should also be tested to improve fertility and maintain the tree’s vigor. Shelterbelts can also be useful for providing an optimal microclimate for apple trees.
Control: Management Of Insect Pests
Good sanitation practices should be followed to reduce the occurrence of insects. All dead or decaying wood should be removed and disposed of properly. Tree pruning should also be done following standard pruning practices. Insecticides and miticides may sometimes be used, depending on the pest.
Control: Management Of Fungal Diseases
Fungal diseases can be managed through preventive measures such as planting resistant varieties and proper pruning. Regular applications of fungicides may also help control the spread of the disease. Trees should be inspected regularly and any signs of infection should be treated immediately to prevent further damage.
Control: Prevention Of Bacterial Infection
Bacterial infections can be prevented by providing good care to apple trees. Avoiding over-fertilization, waterlogging and over-irrigation will help keep the tree healthy and reduce its susceptibility to infection. If infection is already present, applying copper-based fungicides and bactericides can help stop its spread.
