Question
We live in White Plains, NY (10605) and have a problem with our lawn that I've never seen before. I replanted after a hot summer that killed our lush green lawn. Put down about 1/4 inch of rich top soil and then seeded and watered. White nodules are popping up through the lawn surface in the general area where we had a large Norway maple tree removed a few years ago. The stump was ground below grade and filled with top soil. The object are not mushrooms. They begin about the size of a dime and "grow" to the size of a baseball. They are very hard and require a tool to pry them out, leaving a 3 inch hole. I don't know if this is a fungus, or spores, or rotting roots from the old tree. But they are making a mess. When I remove them, they return about a week later. Ideas/remedy appreciated. Scotts said they had no idea what we have.

Answer
I KNOW this is a Fungus.  Possibly attached to decomposing roots.

While I wait to find this out (I have several emails going out to a bunch of people much smarter than me who specialize in Trees and Fungi), I have some things to tell you about Tree Stumps that you may not be aware of.

Ever hear of White-Rot Fungi?

Here's a cheat sheet you will find of interest:

http://www.hawaii.edu/abrp/Technologies/fungus.html

You have Tree Stumps.  You have Tree Roots.  Trees are wood.  Wood is Lignin.

It takes YEARS for Lignin to decompose.  Underground, it takes MORE YEARS.

The Joint Genome Institute points out that White-Rot Fungi -- so named because they turn tough Brown Lignin into soft White Cellulose -- 'are the only microbes capable of efficient depolymerization and mineralization of Lignin':

http://genome.jgi-psf.org/whiterot1/whiterot1.home.html

Get to know and LOVE your White-Rot Fungi.  They and they alone are in charge of making your Tree stumps vanish.

Some quick notes on Fungi: They are ALL aerobic.  They ALL need moisture to work.  Wood decays fastest at higher temperatures; below 50 degrees F, decay slows considerably as the Fungi metabolism drops, and at lower temps, all Fungi go dormant and their work comes to a halt.  Since Norway Maple is a dense hardwood, you can expect this Tree stump to be around for a very, very long time.  Yes, you removed the Maple, ground it below grade, filled with soil.  But PLENTY of Stump was left in the ground.  For one thing, the Stump pieces were probably mixed in with the Soil.  For another, you still have lots of roots and plenty more sold Stump below the ground.  If you had a Green Lawn growing over that site, the Grass in the area would be gone.  You'd replace it, and it would die again.  This is going to happen until there is NO MORE STUMP left there.

Removing the Tree was a good idea.  You probably opened up a lot of the ground to some full Sun when you did that.  Unfortunately there is more to it.  The only way to solve this problem is to remove every last piece of ground and un-ground stump from the Soil OR grow something else there.  The White Nodules are the least of your worries -- it's not the symptom that's the problem, it's the Stumps that's the problem.

Cornell University scientists at the School of Engineering have studied ways to speed up the way Fungi break down the Lignin in wood.  The school published their findings, 'The Effect of Lignin on Biodegradability', and posted them online:

http://compost.css.cornell.edu/calc/lignin.html

They state: 'Adding small quantities of Nitrogen to woody materials can increase Lignin degradation rates.'

Other authorities point out the Sugar is the perfect White-Rot Fungus food; 'feeding' those areas will help to accelerate the breakdown of the Norway Maple Wood.

Still, this is daunting.  There has got to be a better way to get rid of those stumps.  Len, don't even THINK about putting a foot or two of topsoil over those areas.  Submerging them in soil will slow down decomposition (your great grandchildren may still be dealing with this problem) by severely limiting the Oxygen available to those aerobic Fungi.

Any Grass you plant will struggle and eventually fail the way all Grass fails when planted over old Trees that are no longer there.  Look through my previous q's and a's -- there are lots of people with this problem, and it can last for DECADES.

You need some heavy equipment that will physically, totally remove those dead stumps and their roots, or Plan B.  Good luck.