Willow trees are popular for their ornamental value as well as for shade or privacy screens. Although these are typically low-maintenance trees, willow tree problems are sometimes caused by pests or diseases.
Caterpillars often cause damage to the leaves of willow trees. According to Savatree.com, bagworm caterpillars cause defoliation of willow tree leaves and twigs. Other willow tree pests include gypsy moth caterpillars and willow leaf beetles.
Fungi or Bacteria
Dark brown spots on the leaves of willow trees may be caused by black canker. Willow scab is a type of fungus that can kill a willow tree quickly. Willow blight is a term that refers to a willow tree that has been affected by both willow scab and black canker.
Young willow trees require some attention to avoid problems. They need to be kept moist, especially in the heat of the summer. Removing broken or dead branches and trimming branches that touch the ground are ways to help young willow trees stay healthy.