Yes, it does work. But as you mentioned, they just fly in from other areas.........

Application timing is extremely important. The grubs are nearest the soil surface in the last and first weeks of March/April and July/August. Application of what ever you use should be timed to these dates.

As petzold6596 has already indicated timing of you app;ication is very important. Milky Spore Disease, "Bacillus popilliae", is a bacterium that adversly affects the grubs but only during an early stage of development and only if they ingest it and the proper time for application is just before the eggs hatch so this bacterium is down in soil where the newly hatched larva will be ingesting it. Spreading the bacterium in the spring is not necessarily a waste of time and energy but none of the larva will be harmed by this bacterium then, they are simply too big.
What I have seen in my yard is that the Japanese Beetles tend to be more attracted to plants that are under stress then they are to plants that are growing in a good, healthy soil that are strong and healthy and growing happily.

You may not be able to tell if milky spore is doing it's job until 2-3 years after application. As mentioned JBs will not feed on healthy plants. The only plants they fed on this year in my yard was the elm trees that received extensive ice damage and were cut to tall but branch less stumps. These trees were obviously stressed when new growth started and they have managed to out grow the beetle damage. I have many different plants and the only other plant that was touched was a canna lily. I caught it while there was only one beetle on it and plucked and killed that beetle. One beetle will attract more so at first sign pluck them from your plants.

JB lay their eggs in June/July. Larva feed near the surface in July/August and dig deeper to hibernate the winter. The larva crawl up in March and are near the surface in March/April. They pupate into adults May/June and the cycle begins all over again.

petzold6596, Japanese Beetle adults do not appear, at least around here, until July so they could not be laying eggs in June. They do lay the eggs that become the grubs in August, kind of pretty much hibernate during the coldest months and come back bear the surface when the soil warms in the spring to pupate and then emerge in, around here, July. So while what you wrote may well be true for New Mexico it is not correct for northern Ohio.

Do not waste your money on Milky Spores. Very expensive and they did NOT work for me. 7 years after the labor intensive work to apply the spores, large sections of the turf of my lawn was being destroyed by the grubs and you could literally see the Japanese beetles emerging from my yard. The companies recommendation was to mail them some of the grubs so they can analyze them.

Do not waste your money on Milky Spores. Very expensive and they did NOT work for me. 7 years after the labor intensive work to apply the spores, large sections of the turf of my lawn was being destroyed by the grubs and you could literally see the Japanese beetles emerging from my yard. The companies recommendation was to mail them some of the grubs so they can analyze them.

Also, I posted this before, why was it deleted?

7 years after the labor intensive work to apply the spores, large sections of the turf of my lawn was being destroyed by the grubs and you could literally see the Japanese beetles emerging from my yard

So...You applied it 7 years ago and expect it to still be working?? You need to reapply every year, twice a year (early spring and late summer) would work even better. You should really follow directions instead of saying it doesn't work.

Many people do not understand that Milky Spore Disease, Bacillus popilliea, is a disease and that it takes time to work and does not instantly kill the target and as a result they tell you it does not work. If Japanese Beetle larva are in fact killing large portions of anyones lawn that is due more to poor management, improperly caring for the soil, so insect pests can live and grow there.
Pouring synthetic fertilizers and poisons on your soil in an attempt to make grass grow is not good practice and is very un environmentally friendly. Those synthetic things also do serious harm to the friendly, beneficial, insects that would naturally control what we term as pests if we left well enough alone.

taz, milky spore bacterium does not have to be reapplied on an annual basis. If there are host insects in the area, it can live on perpetually.

However, it is worth mentioning that milky spore inoculate simply doesn't 'work' in all locations. It depends upon the soil type, climate, rainfall, and other factors.

I am very curious as to the location of sas1414. Japanese beetles have become a severe problem in some parts of the country...improper management has nothing to do with it.

My Bad! My mind is gone. I was thinking about some encapsulation tests being done with a totally different product. Don't know how I connected the two??

Yes, I did my research and I am very eco-friendly with my lawn. Milky Spores are very time consuming to apply, as you know, however 25 years of safe grub prevention was appealing to me with 4 kids, a dog, garden and well water. My neighbor thought I was crazy as he watched me apply the powder.......which took a good part of my weekend. And years later he was the one to point out seeing the constant stream of Japanese Beetles emerge from various parts of my lawn like swarms of bees. At the time I didn't think much of it until the skunk holes and dead turf showed up. I gave it time thinking the directions said the bacteria grows and spreads within the larvae.

The grubs were found throughout the entire lawn but 1 area of approx. 1/4 acre was infested.

We are located in central PA. But I would think this would not matter as the bacteria is supposed to spread with grub presence, correct?

I am NOT a supporter of chemical containing grub killers however I felt I had no choice at the moment. Within a short period of time, problem solved.

(And my original post that was deleted was posted back in 2009)

Milky Spore doesn't really work. The Japanese Beetles will just hatch in your neighbors' yards and then fly to your yard and eat your flowers. It's also VERY expensive. You can get some Spectracide to apply to your grass and kill the grubs much cheaper. The beetles from the neighbors' yards will still fly to your yard so you need some sort of chemical systemic to apply to your plants.

So what you are saying is that it doesn't work where it isn't applied! Doh! Spectracide kills everything including all the beneficial insects that eat the pests and it pollutes our environment.

Apllying a broad spectrum poison such as that Spectricide is not going to keep the adult Japanese Beetles from elsewhere from coming into your yard, but as Taz stated that poison will kill of any beneficials it contacts as well as any pests. Far too many people think Milky Spore Disease is a contact poison and if after the allpy it they see adult Japanese Beetles they conclude it does not work, even if those beeltes came in from a far distant place. Since MSD must be ingested, eaten, by the target grubs people sometimes assume that it does not work when it is applied at the wrong time or if the grubs are not in a treated area and do not ingest any.
Milky Spore Disease does work, but it will not provide the immediate gratification some people seem to need. Spectricide, Grub-X and all of those similar poisons are very detrimental to the environment, and there is some evidence that the active ingrediant in them can, over time, cause endocrin damage if young children are exposed to them.

And the other problem is.........there are more than 1 kind of grubs. Milky Spores are "supposed" to be effective for Japanese beetle grubs.

I've used milky spore granules on my lawn and gardens with major success! The JB's were killing everything, especially green beans, melons, grapevine and blackberry. I also bought nematodes that are mixed with water and sprayed onto the ground, then watered in. After 3 years of heavy infestation, they are gone! I found a few on my grapevine and moved a bird feeder next to it, no more beetlrs for 2 weeks now. I also planted a 20' x 20' patch of four o'clocks at the west end (about 100 yards) from my veggie garden. They are attracted to the plant, and there's a toxin in the leaves that kills them. I believe these 3 things combined have rid me of these pests.i hope this helps.

Michele Bush: where are you? I am trying to find conclusive evidence that Milky Spore can be effective in Zone 5 (in my case, southern NH), with our harsh winter temperatures. I've heard the bacteria/spores can be ineffective in climates that are too cool. Also, I've read the soil must be at least 65 degrees FOR AT LEAST 3 MONTHS for the bacteria/spores to be effective. Any truth to this?