Milky Spore to combat Japanese beetles

[8piecebox]

I spoke with some folks from the Chicago Botanical Garden here about using milky spore to combat Japanese beetles and was told it won't work this far north because our freezing temperatures kill off the spores every winter. Apparently, it takes several seasons of application for there to be enough spores to seek and destroy enough grubs to prevent a significant Japanese beetle population each season. With the spores getting frozen every winter, it makes me wonder if local garden centers up here that stock the stuff are taking advantage of people's ignorance (mine included up until now).

Comments?

Thanks folks!