Answer: Milky spore disease has been found to be less effective in cool, wet, heavy soils, as can be found in parts of New England. There is recent evidence also that the disease is simply not as effective today as it was when first tested; speculation as to why ranges from the possibility that the beetles have developed some resistance to it or that the infection rate is only sufficiently high when used in very high density grub populations. It is also true that in order to be effective the milky spore must be applied over a large enough area to preclude adults flying in from elsewhere as could happen for instance if only one yard in a subdivision used the milky spore. It also takes several years for the infection to peak and show effectiveness.
In sum, one of the most effective and simplest control measures is to experience a dry summer.
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