Absolutely. This time of year in FL is great for beneficial nematodes. You will get the best results when the lawn is fairly well saturated with rainwater. Beneficial nematodes move around on the moisture in the soil so if you spray on dry soil, you just wasted your money. If you must irrigate to get the soil moist enough, you might do about 1/4 of you watering first, then spray the nematodes, then finish the watering.

By the way, as you know these are not the pesky root knot nematodes that afflicts Florida soils. If you just talk about nematodes down there, keep in mind that you are talking about one kind and EVERYONE else is talking about the other.

The beneficial nematodes work by carrying a disease to the grubs. Nematodes enter the grub by whatever orifice they can find. As they enter the grub, the disease they carry is wiped off onto the grub. The grub is almost immediately paralyzed and dies in less than 48 hours. The nematode lays about 250,000 eggs which hatch in a few days. Then they feed on the diseased grub and, if the soil is moist enough, crawl away looking for more hosts.

Thanks dchall, yeah everyone here in FL, is thinking of Root Knot Nematodes which is different. Any idea if the Beneficials attack the Root Knot types? That is something I haven't seen mentioned in all the pests BNs control.

I am going to order a BN combo, steinernema feltiae and the Heterorhabditis bacteriophora which is the type that is better for the grubs. The other type works on leafminers, fleas, cutworms etc.

I am going to try sort of like a worm bin so I can cultivate many generations of Beneficial Nematodes so I can always have them on hand, considering they are so expensive when you order a single batch of a millon or 5 million of them. I finally found a site that mentioned someone doing this, using a Rubbermaid type container (20 gallons) filling it with 1/3 of moist compost, and then buying mealworms, silkworms, and crickets and then unleashing the beneficial nematodes. The worms died quickly like 2-3 days and same with the crickets. In 10 days or so the dead insects were crawling with new baby nematodes. Then some can be used in the yard, while the rest can stay and start the process all over again with fresh mealworms and crickets. I'm guessing the mealworms and crckets are a lot less expensive than having to order the BNs 2-3 times a year, especially when you factor in 2 day air delivery, which isn;t cheap.

From reading the forums and listening to organic folks on the radio, root knot nematodes seem to go away when you have a mostly organic program going on. Some have said it is as easy as spraying molasses (3 ounces per 1,000 square feet) every month.

Good to know. I never tried molasses before. I do use coffee grinds occassionally though.

I found this info
Successful use of milky spore disease requires attention to environmental conditions, including temperature, moisture, soil structure, pH, and soil type. Efficacy of the disease may vary depending on cold temperatures; the spores are very cold-sensitive. Ideal soil temperatures for spore development during grub attack are between 60ð and 70 ðF (19ð and 21ðC). In cooler climates, like the Northeast, milky spore may take longer to spread than in warmer climates. It is important to know the soil temperatures within the profile during the fall and early spring when grubs are active.
I have been using Milky spore for over 15 years with excellent success.

Ok I was looking online and I still have no answer as to why the Grubs would come out of the ground at night? I thought they live underground and feed on the roots. Why would they come out at night and feed on the surface? I've never seen grubs at night and I've been out at 2am just to see if they are swarming or something. Every morning there are new holes and not from digging raccoons either. They are the exact size of the grubs and not holes from moles or voles. Can anyone explain this?

The answer to your solution is to get Dylux water it in. Follow all directions and your problems will be resolved.

I just want to know why they come out at night as everything I read doesn't suggest that they do come out at night, since they feed on roots. They only come out of the ground when they are adult beetles as far as I know. Not sure what Dylux is and I'm not about to start using chemicals now.

Not sure why they surface and where they go in the morning?
The ground is moist and they will surface.

My question is will beneficial nematodes attack grubs in this stage or are these too developed?
Yes the nematodes will attack grubs in all stages. And the dead ones will make more nematodes.

Just wondering if this is still the very larval stage that nematodes attack?
A grub is the larva stage.

I'm thinking of ordering the Guardian/Lawn Patrol combo.
Miky Spore can take 3 years to really get going. Also it ONLY kills the Japanese Beetle Grub.

The lawn is obviously swarmed with grubs from the yellow spots from them eating the roots and killing patches of grass, and also the amount of holes and also the Raccoon and mole activity during the evening.
You need to actually scoop some grass up and really see what you have.

I did apply Milky Spore last spring and also just again last week to see if this would help. No immediate results, so I'd like to unleash the beneficial nematodes to clean up the rest of the grubs still present and to build up a super colony of the beneficial nematodes hopefully to survive until spring and then really go to town and build up an army.
As stated before it can take up to 3 years to really get going.
To speed up the process you would need to be patient.
I mentioned dylux because it works immediately and lasts for 1 day only.
I sell Milky Spore and if you were buying it from me I would want you to be satisfied.

Like you said Milky Spore only kills Japanese Beetle grubs. Can you identify the grub in the first post? Those are the only type of grubs I see under the grass and yes I checked under the grass and there are lots.

Not sure waiting 3 years is a smart strategy especially if even by your own words Milky Spore only kills Japanese Beetle larvae. If the grubs I have were say Chafer Beetle larvae (and maybe they are?) I'd be throwing money away, as well as waiting 3 years to finally have a decent yard.

Weird thing is the front lawn is a mix of grasses /weeds and there are no regular watering going on and I see no grub activity or moles/racccoons/voles etc. Almost seems like the more care you give your lawn the more problems happen initially until the grubs are under control.

Go here
http://www.hgic.umd.edu/content/documents/white_grub_ID.pdf

Hello,please bear with me; new. The information here has been a great help. I think I have bigger problems though. Japanese beetles has been invading for the last two years; but also the surrounding neighbourhood and there is bushland a block away from our homes. Can anyone suggest what we can do?

So here is an update. I did buy beneficial nematodes. First batch was the Steinerneima Feltiae from Amazon (Scanmask is the company). Weeks later I see no difference. I even set up a rubbermaid 18 gallon bin filled with 4-5 inches of compost that was moist and used the remainder of the beneficial nematodes mixed in the compost well and then I introduced several grubs and mealworms expecting them to be dead in 48 hours or so. Weeks later the worms are still alive and so are the grubs, so I am guessing the beneficial nematodes weren't even alive.

Before I saw the lack of results from the first batch, I bought 2 other varieties from buglogical.com (Heterohabditis and the Steinernema Carpocapsae). With the 3 different strains of Beneficial Nematodes I was expecting joy but several weeks later I still see no difference. With these 3 varieties I should not still see ant mounds or slugs or the grubs. By the way I ordered 50 million of the last 2 varieties in which they claim 50 million would cover a half acre. The area I treated was less than 1/10 of an acre, heck probably 200 square feet. Using 2 of the 50 million batches is would effectively cover a whole acre and I still don't see results in a small 200 sq foot area which tells me these things weren't alive. I also started 2 other containers with compost and added 2 different strains in each container and added mealworms and grubs and they werent dead within 2 or 3 days and are still alive today over 2 weeks later, again telling me the beneficial nematodes were not alive. So to make a long story short $200 spent and no results. Very disappointed.

That is bad news, pickapeck. I can buy them locally but they come from this place in Colorado.

Did you water the ground real well after you applied them?

Yes, I watered the ground in very well before I applied them which I tried a hose end sprayer but it kept clogging so I applied directly over the 200 sq foot area with a watering can with fine shower stream. Then I watered them in after wards with a bit more water to help them in the soil. I was initially worried the ground was dry and to make sure to keep the area watered over the next week. Being in Florida with sand, the water is sort of hydrophobic and we had up till then been having a drought. I asked the buglogical company about this concern and they just said make sure it is well watered.