Hello,

Based on what I see in your images, it looks like your crabapple tree is indeed showing symptoms of apple scab, a common fungal disease caused by Venturia inaequalis. The yellowing and wilting of leaves with brown edges are typical signs. Pruning and mulching are good cultural practices, but if done improperly, they can sometimes contribute to stress on the tree, which may exacerbate the issue.

Here is information on apple scab and other crabapple diseases at these links:

Apple scab - Integrated Pest Management (msu.edu)

Crabapple Diseases (psu.edu)

Here are some management tips based on information from educational sites:

Fungicide Application: Fungicides can be effective in managing apple scab. It’s crucial to apply them at the right time, typically from green tip through midsummer1. For small trees, homeowners can apply fungicides if they follow the label instructions carefully.

Cultural Practices: Planting disease-resistant varieties is the best long-term solution to prevent apple scab. Pruning and training trees to allow good air circulation can also help reduce the disease’s impact. More information is at this link:

Apple Scab | Yard and Garden (iastate.edu)

Leaf Litter Management: The fungus overwinters in fallen leaves, so cleaning up leaf litter in the fall can reduce the inoculum for the next season.

Remember, it may take several years to get apple scab under control, and repeated infections can weaken the tree.

I recommend you get a precise and confirmed identification of the problem with your crabapple tree. Below are some options:

OPTION 1:

For a confirm 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 too.

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 on submitting a sample to MSU Plant & Pest Diagnostics Lab:

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

OPTION 2:

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

Find an Arborist (treesaregood.org)

I hope this helps!