Question
Hi Jim we have a weeping willow that hase new growth and ther are brown spots on the new growht (branches and leaves). Is this a diseases Is this something to be concerned with and if so, what is your recommendation for treatment?

Thank-you,
Cliff  

Answer
A leaf and twig spot disease on willow, caused by the fungus Marssonina, can result in unsightly foliage on many kinds of willow. The disease can be especially severe on young willow leaves and stems soon after bud break in the spring. It is favored by moist weather, and can remain a problem during summer when weather is moist. Although the disease can be aesthetically damaging because of the unsightly appearance of the foliage, generally there is no significant damage to the growth of the tree.

Symptoms of the disease on the leaves and twigs appear as rather small, brownish to black, irregularly shaped spots. These spots, or lesions, generally have small white centers and may occur on either side of the leaf, depending on environmental conditions. If the spot is larger, there may be several white specks within it. The white specks contain thousands of spores, and are most often seen during moist weather. Lesions may be darker on the twigs than on the leaves. Twig lesions may result in death of the twigs.

Good sanitation procedures, such as pruning out dead and diseased twigs and raking up fallen leaves, can help control this disease to some extent. However, pruning large trees is generally impractical, if not impossible. Raking up and destroying fallen leaves throughout the growing season, and especially in the fall, is important.

Fungicide controls-Two to three spring applications of Bordeaux (6-6-100) beginning when leaves are first visible. Repeat at 10-14 day intervals.