Fuzzy white fungus (?) on my Manzanita trees

[jennyjune]

I live in a mountain community in California. This spring and summer, I noticed a fuzzy white substance on some of the leaves of some of my manzanita trees. It is not apparant on every manzanita in my neighborhood. Does anyone know what it is? If so, how do I get rid of it?

Baffled,
JennyJune

[opabinia51]

Try spraying the leaves with a soapy mixture for now. In the future, use an aerated compost tea (sometimes you can buy this but, most likely you'll have to make it. FREE!) Anyway, spray the tree with the tea. That should do the trick.

[Newt]

Hi JennyJune,

I couldn't find any information about white fuzzy substance on the leaves of Manzanita - Arbutus menziesii - Pacific Madrone. You might want to hold on to this site about these trees. For insect and disease info scroll down to 'Damaging Agents' near the bottom of the page.
http://www.na.fs.fed.us/spfo/pubs/silvi ... ziesii.htm

What you describe does sound like either powdery mildew, gray mold or possibly downy mildew which are all fungal infections. Opabinia's compost tea spray recommendations should be helpful. You could also make one of these solutions.
http://www.ghorganics.com/page15.html

Newt

[opabinia51]

You know, an hour after making the post (when I was kilometers away from a computer) I remembered that milk does a handy job on invasive fungi. And now that Newt has possibly identified the fungus.... Milk is intended for powdery mildew.

So, dilute the milk 2:1 with water and spray the infected foliage with it.


Still use the compost tea though, as it will prevent a re-infection.

[Newt]

I thought about the milk for the powdery mildew too, but I'm not sure that's what it is and thought that the others might be more comprehensive. Anyway, it's a good idea to hold on to that recipe as it does help with powdery mildew.

Newt

[opabinia51]

Actually, the milk would be the most comprehensive if the trees are infected with powdery mildew. The soap would just be a precautionary tactic and wouldn't do anything to combat the fungus itself.

Milk however would definately fix the problem and the use of compost tea would provide a healthy population of micro and macro organisms to combat exploitative fungal infections.

My recommendation is to definately use the milk option and follow up with annual aerated compost tea applications