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Shot hole treatment

Posted by outsideplaying 7/No. Ala (My Page) on
Fri, May 12, 06 at 8:54

Can anyone recommend a specific product for shot hole fungus treatment for laurel-family shrubs? I've done a little research on the internet & find mancozeb recommended, but can't find exactly which product contains this ingredient. Also, what and when is the best application strategy. Thanks.


Follow-Up Postings:

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RE: Shot hole treatment

Try daconil 2787. Ortho makes a product called Ortho Multi-Purpose Fungicide that is daconil. I would spray the plants then at 2 week intervals. I would also remove any dead leaves that fall to the ground.


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RE: Shot hole treatment

Thanks a bunch auhort. It's sometimes hard sorting thru all the different stuff out there and making sure you read the fine print. I don't like to use sprays that harms amphibians, butterflies, birds, etc. so will check that out also.


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RE: Shot hole treatment

Click on each of the topic areas for information regarding the active ingredient in Daconil (chlorothalonil).

Are you certain you have shot hole fungus and not one of the shield bearing leaf miners? (Just asking.) I've only seen them a zillion times but I CANNOT find a good image!!!! Perfect little holes, very easy to mistake for shot hole.

Here is a link that might be useful: Read it and weep....


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RE: Shot hole treatment

Prunus (laurel shrub) shothole problems are the result of a bacterial leaf spot, Xanthomonas, not a fungal pathogen as is more common with shothole on deciduous members of that family. Treating with a fungicide is useless. An antibacterial spray like streptomyacin can help if timing is correct, but it's expensive and to my knowledge, difficult for homeowners to obtain.

These shrubs can usually tolerate quite a lot shothole without further problems - it tends to be more cosmetic than physically damaging and is typically caused by overhead watering. Unless this is a very obvious and visible hedge (like along a sidewalk), I generally recommend to my clients to employ the "ten foot rule". Step back 10 feet from the shrub - if you can't see it, don't treat it :-)


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RE: Shot hole treatment

That's a good one Gardengal! I think I like the 10-foot rule better than any other solution, especially since my Otto Luyken has had these holes for about 3 years and is now a 4x4 foot shrub.
Rhizo, I'm fairly sure it's shot hole, but I'll check in a couple of my reference books at home and see if I can find an example of the leaf miners to make sure. Other than the leaf holes, Otto looks healthy.
The main reason I'm asking is that I've put a couple of schip laurels in a foundation bed I'm redoing and want to avoid any holes in those if possible. Thanks to everyone!


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RE: Shot hole treatment

Pam, great rule!
Without knowing about its existence I implemented it for myself.
My schipkaensis grow as a backdrop and a screen, so as close as viewer (not me) could get to it is about 20', so I left it alone.
In a spring I collect fallen brown leaves and that's it.


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RE: Shot hole treatment

I like the 10-foot rule!! Sometimes we can love our plants literally to death...

I think Otto Luyken is more susceptible to shothole than other English Laurels in our region. I had a 'Schipkaensis' at my previous home and never saw any shothole. It was a beautiful plant - but kinda boring. Just a green blob, but good as far as green blobs go! :D


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RE: Shot hole treatment

Hello

I am sorry - first post and a *real* beginner. We just moved into a new property in London and found that the front hedge (which we believe to be a Laurel) has some sort of infection.

I have tried researching on the net and on some books but cannot find much informaton. Can anyone detect hether it is shothole or something else?

I am attaching a link with pics.


















Many thanks for any help you could provide!

Cheers

Alex


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RE: Shot hole treatment

The distorted leaves suggest mildew. Look for furry white fungal growth underneath badly affected leaves.

Shothole disease tends to cause holes without major distortion oor curling of the leaves. It can have a bacterial or fungal cause but the symptoms are pretty much the same.

Check the branches for any oozing cankers. Laurels are prone to bacterial cankers which can cause yellowing and distorted leaves, eventually leading to leaf drop. Generally combined with shothole symptoms since the same pathogen causes both problems.


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RE: Shot hole treatment

thanks s&b.

I have seen a white powder under the leaves at times. Not all leaves just some - a lot fewer than the affected leaves.

I have checked the brances - did not find any oozing cankers.
I did a search online and saw recommendations involving Neem Oil, Baking Soda and a fungicide (Baylaton).
http://hortchat.com/info/powdery-mildew

Any other suggestion perhaps - the plants are sadly pretty badly affected but we really would not want to lose the front shrub.


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RE: Shot hole treatment

If I were to severely prune back my laurel, or stripped off all the leaves. Then sprayed it with the fungicide. Would the new growth come back as healthy, hole-free leaves? My laurel is closer than 10 feet -- and its UUUUh-GLEEE!


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