The label should have that information.

Thomis:

Milky spore is available in two forms, that I know of. There is the pure spore, available in small amounts, but best purchased in 44 ounce cans at a price of about $80. Nominally, one of these cans can cover 10,000 sq. ft., but in actual experience will cover much, much more, if you are able to properly distribute it. Applicators sold with the pure spore consist of a long, cardboard tube with the business end equipped with openings much like a can of ground black pepper or other spice. You fill the tube with pure spore, than walk along bumping it on the ground, attempting to drop anywhere from 1/2 to 1 teaspoon on a recommended 4-foot grid. This procedure is necessarily imprecise, but the objective is coverage, not precision. I have found, by actual experience, that I can expand to an 8-foot grid or even larger with little to no loss of effect, and the amount dropped with each bump can be miniscule. I used three 44 ounce cans on my own acre, but took a single leftover can to my son's place where I did two acres. All of my Japanese beetles were gone within about one year, but so were his. That taught me something. This is a biological product, and if conditions are right, it will propagate itself over a very wide area. It spreads by infecting beetle larvae in the ground, which then explode and produce millions of new spores. It slows or stops propagating when it runs out of larvae to infect. I applied milky spore to my place in July, and did my son's property in August, but I don't think it makes much difference what time you do it during the summer months.

A common formulation of milky spore sold today is a granular product, consisting of a very low percentage of active ingredient mixed with a carrier designed to make it possible to apply with a broadcast spreader. This makes it more convenient to apply, especially if you already have a broadcast spreader (the cardboard tube applicator costs a little over $10). Whether you choose the pure or spreadable product is a choice for you to make, but in terms of cost I think you get a lot more active ingredient on the ground with the pure spore, at the cost of a slighly more complicated method of application.

I have found milky spore to be effective against a range of beetles much wider than I originally thought. In addition to eliminating JB's, it has also wiped out the tan/brown night feeding chafer beetles (that love plum leaves) and even the larger, green June beetles. When I applied, I had plenty of product (about $300 worth) and went about 40 feet into my neighbor's properties on three sides. That may have helped me, and it certainly helped the neigbors.

Whether you mow before, after, or during the application of milky spore is irrelevant to the action of this product. The point is to get it on the ground, and it may be helpful to have a little rain shower after you do to wash it in. I suppose that if you mowed right after application, while the pure spore product is still dry, it might actually help to spread it between the grids where you have placed it with your dop stick.

Don Yellman, Great Falls, VA

thanks, Jellyman. That's a huge help. I doubt that information is on the label.
~Thomis

I'd recommend doing it right before it rains or else going over it with a hose when you're done to wash it in. I used a measuring scoop and dropped some every few feet in a little grid and ended up with little white piles all over the yard. I was worried about my dogs eating it so I went over it after with a watering can to wash it in. It dissolves very easily. I used the pure stuff as my spreader broke and I don't want to bother fixing it. It's probably best to do it late summer when the beetle larvae are near the surface, but the milky spore should be able to sit dormant for as long as it takes for it to find something to infect.

Thomis:

After a little thought, it occurs to me that there might be some advantage to mowing just before applying milky spore if you are going to use pure spore and the applicator tube. You should be able to easily see each the spots where you have deposited a small amount of the product, and that might not be so easy with tall grass. No point in covering the same territory twice. Athena's measuring scoop method may work ok for a small area, but would be pretty tedious when doing an acre or more. The bump stick is fast, and requires no careful bending over. I think the applicator is worth the 10 bucks for applying pure spore. Applying on a day when the grass is dry helps to keep the product from clogging up the outlets at the bottom of the tube, but after that rain or a sprinkle with the hose would be helpful.

One other thing to keep in mind is that this is a biologically active product with a short shelf life. I would suggest purchasing just before application, buying no more than you can use at one time, and don't try to store any for next year. All things considered, I think early July would be about the best time to apply it, but I don't have any scientific evidence to back that up.

Don Yellman, Great Falls, VA

Don, your advice here is excellent. I've been agonizing over doing applications here for clients where JBs have been out of control and sevin aps have led to mite outbreaks!

Cornell is now suggesting that from Z6 down the spore may not survive winter but in my Z6 I believe I got amazing results that have lasted about 14 years now. And we have had temps below -20F.

Thanks, this is great. I will plan on applying it in June or July after a thorough mowing and before a reliably forecasted rain event.

Milky spore is not cheap, but it seems that these minor precautions will allow me to make the most of it. Not to mention the long term benefit. The orchard isn't quite an acre but I'll buy enough to apply it to the outlying areas, too. I doubt japanese beetles pay attention to 8' fences!

A brief search with google.com located this info from Penn State

http://live.psu.edu/story/24796

which should be pertinent to your situation.

Here is a link that might be useful: JB grub info from Penn State

A friend suggested 1 part of water to a part of milk as milky spore substitute or as she called "cheap home remedy"for JB grubs. Is this true? She said it was effective in her own garden in eliminating JB and their grubs. Please comment. Thank you.