It's been years ago, but I used nematodes on my lawn as a flea control. It worked to suppress the fire ants too! You do have to use a lot of nematodes. I think I used 50 million to go around my house. I remember having to use a sprayer that had never had a pesticide or herbicide in it. I also remember having to water my lawn before as well as right after I sprayed on the nematodes. They need a moist soil to move about, so if your summer was dry that could have inhibited activity. They do take a while to affect target insects. And, you do have to reapply them each year. Some recommend applications in both spring and fall. Here is a LINK to more complete info.

The natural pesticide Bacillus thuringiensis (Bt) only affects insects. It is harmless to birds, fish and mammals. It is supposed to be most effective against Japanese beetle grubs. The grubs found in southern states are more likely the masked chafer beetle (June bug), but I believe it's supposed to work on them too. Here is a LINK with more info on Bt.

You did not mention keeping the soil moist after applying the nematodes. They must have moisture to move around. Dry soil is the most common mistake people make.

I watered before and after. We had rain after too-- but was it too much rain? Did it wash my friends away. From what I have read I was going to try one more application. It seems like the temps at night are going to drop which I know may not help the nematodes work. Has anyone heard of cedar oil killing them? Supposed to be dog safe too

What exactly is your grub problem? Is the problem that they are killing the grass or is the problem that your dog is digging for them and making holes in the yard?

Lifecycle of the grubs in the NE from Cornell. I would think the nematodes would be most effective when the grubs are active and near the surface. You didn’t say when you used them. They’ll be going deeper soon. Did you continue to water every few days after applying the nematodes if it was dry? Adult traps tend to attract more beetles to your yard and aren’t effective IMO.

I didn’t notice any JBs at all this year.

Mindshift....which Bt strain are you recommending for this grub situation, please? Am curious because to my knowledge, there are no Bt strains that are effective against soil grubs.

Rhizo, that was my initial thought as well! Was about to make a comment to that effect the other day when this thread first appeared but did a little research first (always like to check my facts when I am about to make a pronouncement :-)) and discovered a recently developed/discovered variant of Bt was in fact marketed specifically for lawn grub control purposes - Bacillus thuringiensis var. galleriae (Btg). Sold under various tradenames.....BeetleGONE, BeetleJus, GrubGONE, etc.