Willow Scab: Identifying And Addressing A Deadly Tree Disease

Willow trees can be tall, flowing and majestic. Unfortunately, they are also susceptible to a disease called willow scab, which can leave them looking a fright in a matter of months. If you own a willow tree, it is essential to be on the lookout for signs of this disease so you can act accordingly if it does appear.

What are the signs of willow scab?

Willow scab is a fungal infection that often begins in the spring or summer. The first signs are often observed in the leaves. They may darken and curl up on the tree, almost as if they were preparing to drop in the fall -- yet it is only spring or early summer. If you look closely at the newer, greener branches, you'll notice that dark green pockets begin to form. These are spore pockets; they house the fungal spores and will eventually break open, releasing the spores.

Often, trees that become infected with willow scab also develop other infections and blights since their defenses become weakened. Thus, soon after willow scab symptoms appear, you may notice signs of black canker disease (dark spots on the twigs and branches) or of a caterpillar infestation. 

What should you do if you notice signs of willow scab?

If the disease is caught early before other diseases like black canker begin setting in, it can sometimes be treated. A tree care expert can spray the tree with fungicides as well as insecticides to keep away the moths and caterpillars that love feeding on weakened willow trees. This may give the tree enough protection to allow it to fight off the willow scab fungus and recover.

In many cases, however, tree owners do not notice willow scab until it is too late. If there are cankers appearing on the tree or it is missing a large amount of its foliage, it is probably too late to save it -- and your best option is likely to have the tree removed.

When removing a tree that is infected with willow scab, it is wise to hire an expert rather than tackling the job yourself. A tree care service (such as Arborcare Tree Service) will ensure the wood is disposed of properly in a way that will prevent the fungus that cases willow scab from being spread to nearby trees. If you do dispose of some or all of the wood yourself, burning it is the easiest way to do so safely.