Thornless cockspur hawthorn browning leaves - Ask Extension
Dear CO extension office. My 2 year old thornless cockspur hawthorn appears sick again this year. The leaves are browning at the tips again this year ...
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Thornless cockspur hawthorn browning leaves #873346
Asked June 16, 2024, 5:13 PM EDT
Dear CO extension office. My 2 year old thornless cockspur hawthorn appears sick again this year. The leaves are browning at the tips again this year over the past week. Earlier this spring I gave it 2-3 3 gallon buckets of water but now it’s getting watered with the sprinklers 4 x weekly for 20 min. There are no bugs, I have not fertilized or applied pesticide.
What do I need to do to help it?
Thank you!
Larimer County Colorado
Expert Response
Hi Jessica,
A couple possibilities...this could be hawthorn leafmining sawfly, which is an insect that feeds between the layers of the leaf. Generally you might see the leafminer inside the leaf. The good news is that the damage is cosmetic and won't affect the overall health of your tree. It looks bad and the leaves may drop earlier than normal, but it's not something that warrants control. You can read more here (and see more photos): https://bygl.osu.edu/node/2138
The other option might be frost damage - as the leaves were unfurling this spring, the tips might have been nipped by a cold night or two, since they are fairly tender and sensitive. In this case, there is also no controls needed. The newer leaves are unaffected because they emerged later when temperatures were more moderate.
A couple possibilities...this could be hawthorn leafmining sawfly, which is an insect that feeds between the layers of the leaf. Generally you might see the leafminer inside the leaf. The good news is that the damage is cosmetic and won't affect the overall health of your tree. It looks bad and the leaves may drop earlier than normal, but it's not something that warrants control. You can read more here (and see more photos): https://bygl.osu.edu/node/2138
The other option might be frost damage - as the leaves were unfurling this spring, the tips might have been nipped by a cold night or two, since they are fairly tender and sensitive. In this case, there is also no controls needed. The newer leaves are unaffected because they emerged later when temperatures were more moderate.
