Hello,

The yellowing and loss of leaves in your White Willow (Salix alba) could be due to several factors, including pests, diseases, or environmental stressors. Based on educational sources, here are some potential causes and treatments:

Pests and Diseases:

Aphids, flea beetles, sawfly larvae, willow scale, borers, lace bugs, and caterpillars can infest willows, causing leaf damage and yellowing. More information is at this link:

White Willow - Salix alba | North Carolina Extension Gardener Plant Toolbox (ncsu.edu)

Diseases such as anthracnose, rust diseases, crown gall, root rot, honey fungus, powdery mildew, leaf spots, cankers, and blights can also lead to the symptoms you’re observing. More information is at this link:

White Willow - Salix alba | North Carolina Extension Gardener Plant Toolbox (ncsu.edu)

Willow Scab can cause twig or branch dieback, predisposing the plants to other pathogens and drought stress. More information is at this link:

willowscab.pdf (cornell.edu)

Environmental Stressors:

White Willow thrives in moisture-rich soil and is intolerant to dry soils. Ensure that your tree is not experiencing drought stress. More information is at this link:

White Willow - Salix alba | North Carolina Extension Gardener Plant Toolbox (ncsu.edu)

The tree prefers full sun to partial shade. Check if there’s been a change in sunlight exposure due to new constructions or tree growth. More information is at this link:

White Willow - Salix alba | North Carolina Extension Gardener Plant Toolbox (ncsu.edu)

Treatment:

Pruning affected branches during late winter or early spring can help prevent the spread of diseases. More information is at this link:

White Willow - Salix alba | North Carolina Extension Gardener Plant Toolbox (ncsu.edu)

For pest control, consider insecticidal soaps or oils. However, it’s best to identify the specific pest before treatment.

Fungicides may be used for diseases, but proper identification is crucial for effective treatment.

Herbicides like glyphosate can control unwanted willow growth, but be cautious not to harm the tree you want to keep. More information at this link:

White willow : Salix alba - Salicaceae (Willow) (msu.edu)

Proper diagnosis of the issue before treatment is essential. Consulting with a local arborist or MSU Plant and Pest Diagnostics can provide a more accurate diagnosis and tailored solutions. They can also advise on specific concerns about Michigan’s climate and soil conditions. Healthy trees can better resist pests and diseases, so optimal growing conditions are critical.

OPTION 1:

For a confirmed and precise identification of the problem, I recommend you send all your images by e-mail to the MSU Plant & Pest Diagnostics Lab. The experts there can also provide you with the best treatment options. Their email is <personal data hidden>. Please include your name. The lab will let you know if they need a sample sent. FYI, the lab may also ask for additional images.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details of submitting a sample to MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

OPTION 2:

You can consult a local certified arborist for a more detailed onsite assessment and personalized advice. To find an arborist in your Zip Code, go to this link:

Find an Arborist (treesaregood.org)

I hope this helps!