lawn roots dying
 

Live in California. My lawn is well established, 15 years+. Noticed that the
lawn is dying in certain areas. I go to rake and the area comes up.
Something eating the roots. Lawn appears to be just laying on top of soil. I
have used Scott's Summer Blend fertilizer and followed up with Ortho
Diazinon a few weeks later with no help. Newer areas continue to appear. Any
ideas would be appreciated. Thank you, Steve T.