Hundreds of tiny mounds in lawn - help identify problem?
If anyone can point me in the right direction as to the problem, I would greatly appreciate it.
Background: I live in NE Ohio. In August 2008 we had a landscaper take down about 20 trees from our backyard. He then added topsoil and planted grass. Everything was fine, the grass looked great that fall and into spring/summer 2009.
Then, in late August 2009, I began to notice small mounds popping up....a few at first and then they seem spread out everywhere by October. Most are about 2-3 inches in diameter and maybe 1-2 inches high. The grass is eroded from every mound, so it has become a bit of a problem.
Here are a few thoughts/questions:
1) Is it related to all of the trees we removed? The ground has always been uneven and soft in spots due to the remaining roots, but we didn't have mounds popping up at first. Could the ground have settled resulting in this? Are all those roots conducive to some kind of insect or disease?
2) I foolishly did not use a grub control fertilizer over the summer. I have since read where grubs seem to peak around the time I started noticing the problems, could that be it?
3) Looking at dozens of pictures on the internet, worm casting pictures seem to match mine pretty well. We do seem to have a large number of earthworms, but could they really do all of this?
4) Moles, squirrels digging up nuts, etc.... There doesn't seem to be a tunnel structure that I can tell, just lots of tiny mounds.