Fungus in soil
I have what seems to be a fungus in my grass that is right next to a huge white ash tree. We have dug up the grass and are now trying to dig up the dirt, but I don't want to kill the tree. I heard we must remove 18 inches down in order to get the entire fungus. Is this true or is there any other type of formula we can put on it. Right now we have removed the sod and part of the soil in a square of about 10 by 10 feet. please help :-)
Utah County Utah
First, I would recommend that you get a positive diagnosis of the problem before you do any digging around the tree. You can get instructions and information on taking and sending in a sample here. Once evaluated, they will get back to you with a diagnosis and treatment options. One solution I might recommend is simply removing the turf under the tree and mulching the area. That would be better for the tree anyway.
I am not a tree expert, but removing soil down to 18" around a large tree seems excessive and may not take care of the fungus anyway. I am going to forward your question on to another specialist to address that part.
I agree with Dr. Kopp that the first thing you need to do is get a solid diagnosis. You can get help with that through your county extension office. I also agree that the best thing you can do for a tree is remove the turf around it and put mulch under it. I would not try and remove 18 inches of soil. Most of the roots are actually in the top 18 inches and you would harm the tree. Plus, the chances are really good that you would never get rid of the fungus anyway.
I would suggest either mulching around the tree and leaving it at that, or replacing the turf with some other kind of ground cover that is not susceptible to whatever problem the turf has. The following publications have some good ideas for potential ground covers you could use:
Xeriscaping: Ground Cover Plants - 7.230 (Colorado State University Extension)
Ground Covers SP-99-12 (University of Nevada Extension)
Hope this helps!