Answer: There is one common disease (Marssonia Leaf and Twig Spot) and one insect (Giant Willow Aphid) that can cause the problem you describe. Since it's important to identify the problem prior to treating, you should take a leaf sample to your local cooperative extension office for positive diagnosis. Contact Tonie Fitzgerald at WSU Cooperative Extension, 222 N. Havana, Spokane 99202. Phone 509 533-2048. Good luck with your willow!
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