Question
Hi:
I'm writing from Lynn, MA.

Last year we had sections of our lawn regraded to make it as level as possible.  The contractor used about 80 yards of screened loam and Blue Tag Triplex Seed Mix, starter fertilizer and granular limestone.

The new lawn was graded to the level of an existing lawn.  We were quite happy with the results.

At this time, the new grass is doing fine but continues to sprout mushrooms.  The old lawn has no mushrooms.

Scott's lawnservice is maintaining the lawn and when I presented the problem to them, I was told that when they aerate and re-seed at the end of the season, that should take care of it.  

However, be that true or false, I don't like to awake to a field of mushrooms each day.  Is there a product which will
destroy the mushrooms and their source?  

Answer
Your rich, fertile, forest-dug 'screened loam' is to blame, sir.  Mycorrhizal mushrooms and their spores were active in the topsoil when it was harvested.  Now it's on your Lawn.

Believe it or not, this is actually a good sign.  See this article, The truth about mushrooms in your lawn, from the St Louis Dispatch:

http://www.ledger-dispatch.com/life/lifeview.asp?c=172728

They note: 'If your property has mushrooms, it may indicate that your soil is healthy and a good place for trees and other plants to grow... After a while, the mushrooms will stop forming and the mycelia will live unobtrusively in the soil for another year.'

I agree.

Raking every few days will knock the Mushrooms over without destroying the beneficial microbes that spawned them.  Fortunately, these are different from the Mushrooms called 'Fairy Rings' that appear over areas where a Tree was removed earlier.  Fairy Rings can last for decades, as the wood-dissolving Fungi underground break down old Lignin, a process that takes YEARS.

I don't believe Scott's is right - there is no reason I know of that aerating or re-seeding or both would make any difference to the Mushrooms.  More important:  Is this Mushroom crop a sign that your soil pH is too low?  Get a soil sample over to your local cooperative extension and have it tested asap:

http://www.umassturf.org/services/soil_testing.html

There is a modest fee for the test.  Spring for the full test; you'll not only learn what your pH is and how much more Lime your Grass needs, but also what kinds of fertilizers you should add.

The old wives' anti-mushroom brigade recommends you sprinkle Baking Soda out of the kitchen cupboard to fight Mushrooms.  This might work, but it is not good to destroy the billions of other Fungi down there that are -- I guarantee -- keeping an eye on any Bad Opportunistic Fungi present in your soil.  I'm telling you, those Mushrooms are a good sign, and I think you ought to keep them.

I hope you will think this one over before taking any action.  Thank you for writing.  Let me know if you have any questions.