How to Save My Horse Chestnut Tree

Prevent contamination by keeping other horse chestnuts away from your tree.

Horse chestnut trees can be seriously affected by disease and infection. They are susceptible to leaf miners, small caterpillars that live inside the leaves and weaken the tree. No treatment exists for this condition. Bleeding cranker and mildew are also common infections. It's difficult to save affected horse chestnut trees, but measures can be taken if the problem is spotted early.

Things You'll Need

• Secateurs
• Knife
• Saw
• Fungicide

Instructions

Bleeding Canker

1. Cut off the infected branches with sterilized secateurs (small pruning shears). Branches which are suffering from canker will have dark legions on them. These appear either shrunken, swollen or cracked. Infected branches also have fewer leaves and look unhealthy. Cut the branches back to their healthiest point.

2. Remove infected areas from the trunk with a sharp, sterilized knife. Use a saw to cut through the largest infected branches.

3. Sterilize the secateurs, knife, and saw. Burn the branches and bark to prevent cross-contamination.

Powdery Mildew

1. Remove all the leaves that have white spots or a gray fungus growing on them. This is a mildew which can damage the tree's resilience.

2. Spray the horse chestnut tree with a fungicide containing myclobutanil and mancozeb, to stop the infection from spreading.

3. Remove some of the surrounding trees if the mildew becomes a recurring problem. This will increase the airflow around the tree and help to prevent mildew from forming again.

References

• Daily Mail: Britain's Conker Trees Under Threat
• Independent: Census Call to Help Conquer Horse Chestnut Threat
• Gardeners'World.com: Problem Solving
• TreeHelp.com: Powdery Mildew

Resources

• Trees are Good: Insects & Disease Problems