Now is probably a good time to start scouting for white grubs. Certainly the weather we’ve received this season has made it difficult to guess the appropriate time to begin scouting. However, if you’re likely to see grub damage this season they are going to have to start feeding soon.
Certainly in most organic lawns, grubs are not the problem that the synthetic lawn care industry has made them out to be. To be on the safe side, check the sunnier, drier areas of the property. Use a square mouth shovel to make two slices in the turf at right angles to one another. Peel the turf back and check in the root zone for grubs. Make sure you really look. I would not be surprised to find them to be very small even though it is approaching the middle of September.
If you find more than 6 grubs per square foot it makes sense to treat them. The best natural treatment I have found is the use of parasitic nematodes, Heterorhabditis bacteriophora.
Check out greenmethods.com for more info on biological controls. Make sure you follow the directions for applying Hb nematodes and I’m certain that you will find them very effective in treating your grub problem.