Pussy Willow Problems
Symptoms	Probable Cause
Break In Storms	Weak Wood
Bark Attacked; Leaves Curled and Distorted	Aphids
Holes in Leaves and Girdled Twigs	Bagworm
Branches Swollen And Distorted; Holes; Sawdust And Sap Stains At Base Of Trunk	Borer
Holes in Leaves	Caterpillars
Leaves Consumed; Conspicuous Tawny Egg Masses Present	Gypsy Moth
Foliage Turns Pale or Mottled	Lace Bug
Leaves Wilt and Turn Brown	Midges
Leaves Become Distorted and Cupped	Psyllids
Leaves Are Skeletonized	Sawfly
Leaves and Branches Encrusted With Small Bumps	Scale Insect
Leaves Discolored	Thrips
Leaves Mined and Discolored	Weevil
Leaves Covered With White Powder	Powdery Mildew
Yellowish Spots and Dark Pustules On Leaf Undersides	Rust
Leaves Spotted; Turn Brown; Fall Prematurely	Leaf Spot

Breaks In Storms means Weak Wood
Willows have weak, brittle wood. They often split or break in storms, especially under the weight of ice or wet snow. There is no effective protection from this problem, except to site the trees in areas that are somewhat sheltered from wind.

Leaves Covered With White Powder indicates Powdery Mildew.
Powdery mildew is caused by a fungus that develops mostly on the upper surfaces of the willow leaves. It looks like whitish blotches. If the mildew is serious, spray the willow leaves thoroughly with wettable sulfur once or twice at weekly intervals starting as soon as the whitish coating of the fungus is visible. Collect and discard all aboveground refuse in the fall.
For more information see file on Dealing with Fungal Disease.

Yellowish Spots And Dark Pustules On Leaf Undersides due to Rust.
Some rust diseases that are caused by fungi attack willow leaves. They are signaled by lemon yellow spots on leaf undersides, that later develop into spore-bearing pustules. A severe infection will cause the willow leaves to drop. Although rust infections are not considered serious, they can defoliate young trees. Collect and destroy fallen leaves and prune out affected branches. Spray willow foliage with a copper fungicide.
For more information see file on Dealing with Fungal Disease.

Leaves Spotted, Turn Brown, Fall Prematurely means Leaf Spot.
A variety of fungi cause leaf spot disease on willows. These infections are distinguished by yellow, brown or black dead blotches on the leaves. Often spots come together to form larger patches of dead tissue. Some may cause premature defoliation of the tree. Because leaf spot fungi over winter on diseased fallen leaves, a thorough fall clean up is the best treatment. Gather and destroy the fallen leaves and other nearby garden debris. During the growing season spray affected trees with copper fungicide when the disease causes considerable defoliation.
For more information see file on Dealing with Fungal Disease.