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What is this white stuff on mulch and stump?

Posted by amysun 9 Bay Area, CA (My Page) on
Thu, Nov 1, 07 at 15:05

I need help identify what this is. There is white stuff appearing on mulch that surrounds my lemon tree. This area has become hard and compacted. Here's one shot with a second one that is a closer look (the best I can do). About 2 feet away there's a monterey pine tree stump - the tree was cut down a year ago, and now white stuff is appearing on its sides and top. Here are all the pictures. My questions:

1) Do you know what the white stuff is?
2) Are these white stuff related?
3) How to treat it?

We do want to get rid of the stump, but have not had time or resources to do it so we've left it alone for now. - Amy

Follow-Up Postings:

RE: What is this white stuff on mulch and stump?

I have the same thing on the stump of a pine tree we had cut down about 3 weeks ago. The white stuff appeared over night....literally. It wasn't there one day and it was the next. Anyway, I assumed it was fungi that showed up as part of the natural decomposition process and have left it alone to do its thing -- we're getting rid of the stump and the roots in January and I figure I can deal with a little freaky looking fungus til then.

I'm sure somebody here will know specifically what that stuff is, but I really don't think it's doing any harm on your tree stump. The ground around your lemon tree may be a different matter...I don't know what's going on there. Could be from the decomposing roots of the tree stump nearby.


RE: What is this white stuff on mulch and stump?

You are correct that it is fungus and part of the decompostion process. This fungus will not normally cause problems with other plants in the garden. If you turn the mulch over in another part of the garden after it has been there for a while you will find the samething, part of nature returning the nutrients to the soil.

RE: What is this white stuff on mulch and stump?

Looks a bit like one of the many slime 'mold' species, which are are not fungi (nor molds) at all. They 'move' across many different surfaces, feeding on bits of organic matter as they go. Finding a slime mold on mulch would be typical.

RE: What is this white stuff on mulch and stump?

  • Posted by amysun 9 Bay Area, CA (My Page) on
    Sat, Nov 3, 07 at 10:06

Thank you very much for your responses. Looks like it's relatively harmless. I looked up slime mold on the net, and these look more like vomit and yellowish, and my version looks like neither - it's more like powder that became caked. I'll turn over the mulch this morning and hope for the best.

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