My home is located on the ridge-line between the Ross Valley and the San Rafael Valley. I have a Blue Grass lawn, about 2,500 s.f. The lawn is partially shaded at various time of the day with a protion in the center in direct sunlight mid-day.
The lawn was started from seed in 1987. I think the top soil was not great at the time. About 5-7 years ago I started getting patchy dead spots in the lawn durring the summer months, mostly in the sunney areas and I thought it was a water issue. But more water did not solve the problem. I have come to believe it is the result of grubs. The lawn is also active with some kind of moles. The lawn is often peeled back in the fall (I am told this is done by the racoons looking for the grubs.
I have tried nematodes from Sloat Nursery - quite expensive to get enough - but this seemed to do no good at all. I have treated with diazanon, which is no longer available - but even this was only marginally effective. I am now using Triazicide, contains Lambda-Cyhalothrin with limited success.
I have plug and top dressed the lawn several times over the years. I originally top dressed it with compost generated from my property. I think this might have been when my troubles started. Beetles or grubs in the compost??
The local soil has a high clay content and compaction is a problem. I have plugged once last year, no top dressing and once this year, topped with sand.
What can I do to get rid of my grubbs?