Clusters of brown leaves on crab tree

Question: Hi - Our mature crab tree has developed clusters of brown leaves scattered throughout the green foliage in the last month (see photo). Can you tell me what might be causing this? If it indicates a long-term problem with the tree, is there anything we can do to help it? Thanks!

responder: The Question Asker Replied June 28, 2024, 9:49 AM EDT
response: Hello,  I submitted this question several days ago. When might I expect a response?  Thank you,  Roxanne Weymouth    On Sat, 22 Jun 2024 at 09:38, Ask Extension <<personal data hidden>> wrote:    Dear rocketjs612, Thank you for using Ask Extension. A request for support has been created and a representative will follow-up with you as soon as possible. Questions are usually answered within two business days. You can view this question's progress online. YOUR QUESTION #0144081: Clusters of brown leaves on crab tree Hi - Our mature crab tree has developed clusters of brown leaves scattered throughout the green foliage in the last month (see photo). Can you tell me what might be causing this? If it indicates a long-term problem with the tree, is there anything we can do to help it? Thanks! Ask Extension offers one-to-one expert answers from Cooperative Extension/University staff and volunteers within participating Land-Grant institutions across the United States. If you wish to provide additional comments or information regarding the issue, please login to your account for a complete archive of your prior questions and answers.  This message for informational purposes only. It is not intended to be a substitute for personalized professional advice. For specific local information, contact your local county Cooperative Extension office or other qualified professionals. eXtension Foundation does not recommend or endorse any specific tests, professional services, products, procedures, opinions, or other information that may be mentioned. Reliance on any information provided by eXtension Foundation, employees, suppliers, member universities, or other third parties through eXtension is solely at the user's own risk. All eXtension content and communication is subject to the Terms of Use which may be revised at any time.

responder: eGardener  Replied June 28, 2024, 10:25 AM EDT
response: Hello,  We get an astounding number of questions during the growing season. Thank you for your patience. I can't get a really clear close-up view of the affected areas of your tree. I'm particularly interested in the new growth where a characteristic wilting at the ends of twigs that looks like a hook signals a fungal disease called fireblight. The brown leaves hanging down, coupled with the right weather conditions for the disease makes me think that's what the issue is. It can be precipitated by damage to the tree, like hail, that opens wounds allowing the fungi to enter.  Because I can't definitively say what it is, I recommend sending a sample to the U of MN Extension plant disease clinic for a diagnosis and recommended treatment. Here is a link to their website where you'll learn about their services, prices, and how to submit a sample. Good-luck!

responder: The Question Asker Replied June 28, 2024, 2:20 PM EDT
response: Thanks for your response. Here's a close-up of the end of a branch, so new growth that has turned brown. Does this give you any more information about the potential problem?  Thank you!     On Fri, 28 Jun 2024 at 09:25, Ask Extension <<personal data hidden>> wrote:

responder: eGardener  Replied June 30, 2024, 12:48 PM EDT
response: It's very likely that it's fireblight but the only way to be absolutely sure is with a diagnosis.  Many people feel reassured by looking over the information and photos about a disease that typically affects the tree that it's supposed to affect. They, then, take the recommendations for managing the disease provided by the university researched article. Please refer to the fireblight link provided in the earlier answer for comparison and management.. Good-luck!