Fill Tree Holes to Reduce Mosquitoes

What You Need to Know About Filling Tree Holes

Tree holes can be found in the trunk or branches of a tree and can easily fill with water. This makes them a perfect spot for mosquitoes to lay eggs. Filling holes is one way to help reduce mosquitoes in your yard.

Tree hole

How to fill a tree hole

  • Determine if the tree hole holds water.
    • Tree holes that do not hold water may provide nesting sites for birds or other wildlife and do not need to be filled.
  • If the tree hole holds water, fill the hole with expanding foam used for home insulation projects. Look for a product that is made to fill big gaps and is water resistant. Follow directions on the product label.
    • Expandable foam is light weight, seals the hole, keeps it from collecting water, and is flexible enough to move with the tree.
    • You do not need to clean out the tree hole before filling.

When filling a tree hole

  • DO NOT fill tree holes with gravel or sand. These materials do not prevent water from collecting in the tree and can become a safety issue if the tree is cut down.
  • DO NOT fill tree holes with concrete. Concrete is not flexible, adds weight to the tree, and can damage it.
  • DO NOT drill drain holes in the tree. This can damage the tree.

Other yard maintenance tips

In addition to filling tree holes, follow these simple yard maintenance tips to reduce mosquitoes in your yard.

  • Once a week, empty and scrub containers with standing water, including empty flower pots, bird baths, and trash containers. This should remove mosquito eggs from the inner walls of the container.
  • Drain water from pools when not in use.
  • Remove water from tarps used to cover items in the yard.
  • Mow your lawn regularly and cut down weeds near your home.
  • Keep rain barrels tightly covered or screened.
  • Apply larvicide to containers with aquatic plants and to plants that hold water, such as bromeliads.
Related Resources

Mosquito Control: What You Need to Know About Filling Tree Holes