Rust on Hawthorn

Just looking for more information regarding treatments for Rust. I have a Washington Hawthorn (Crataegus phaenopyrum) and for the first time EVER I have trees afflicted by this fungus. My Hawthorne is afflicted the most and its spread to a CE and an Ume. I’ve treated with fung-onil followed by copper fungicide. There is/was so much rust on the hawthorn I removed whole branches of secondary and tertiary structure. This plant flowers, however, I obviously wont get any this year.

I think I’ve contained the infection on the Ume and CE as I’ve seen no further progression of the disease on those trees. The hawthorn, howeve,r was literally red in color because of the rust infection. It is quite strange this happened as I used dormant sprays and lime sulfur through the winter to be more proactive. I seldomly apply preventative treatments… Has anyone successfully combated a severe rust infection? If so, what was your treatment protocol?

Not sure what else to do at this point, I’ve isolated the hawthorn from the rest of the garden. Thoughts and suggestions appreciated.

If you have any junipers or cedars you should check them and give them a fungicide as well. Do you have any photos of thee disease? One thing is to make sure you sterilise all your tools and whatever else it may have come into contact with.

I took all my tools and soaked them in alcohol for about 24 hours. Then applied choji oil.

I have only 2 junipers in my collection, procumbens and they don’t have any evidence of disease. Nevertheless I sprayed then with Fung-onil and copper fungicide.

Actually I sprayed everything with both of those. Sadly, I’m in central texas and there are native juniper everywhere. Not sure what else I can ship at those point…

Disregard me reply, I just realised the image you posted is a stock photo and not an image of your actual tree.

Please post pictures of your trees, its intriguing because CE is not susceptible, so you may have multiple issues or a misdiagnosis

For sure, it could be possible. I’ll post photos in AM just arrived home and it’s dark.

Other than what you’ve done I don’t think there’s much more you can do. I think it’s a case of being very attentive over the next couple of weeks. How soon can you dose again?

I plan to do weekly applications again this week for 3 weeks. 2nd dose will be applied in the next 2-3 days.

1 Like

Well in San Antonio, we just had week of wet weather with humid overcast days in between rain showers.

Enter Return of the Rust Infection to this Hawthorne.

As can be see in the photos above, just sprayed with diluted lime sulfur to the foliage. I expect some of the new foliage will burn or suffer some damage. I definitely will not cut back hard again, as the infection is nowhere near a severe as the previous episode.

Despite the hard cut back performed earlier this spring the tree appears to be quite vigorous.

I had a small outbreak last Spring. I treated with mancozeb and it resolved the issue. I bought the concentrate off amazon and mixed as directed and applied with a 1gal garden spayer.
Good Luck.