Shadegardener said:Aww - that's unfortunate about milky spore not being effective anymore. I think most of mine fly in but I'll still have to pursue the new stuff.
It is indeed. After the talk last year I did look into this some more and found the following as well as the aforementioned article from Minnesota:
"Commercial Milky Spore powder failed to reduce grub densities in multi-year field trials as well as greenhouse assays."
From:
https://esa.confex.com/esa/200...
According to an article from Cornell on biological control with milky spore, the US government applied over 100 tons of spore powder to over 160,000 sites between 1939 and 1953 which resulted in a 10 to 20x reduction in the number of larvae. But then they say "Recent research indicates that in some regions of the US P. popilliae (milky spore) appears to be losing its virulence against Japanese Beetles. Only 0.2% of larvae collected from field sites showed symptoms of milky disease compared to 1946 with 41.5%. Also, a recent field study in Kentucky showed that commercial formulations of P. popilliae were only moderatively infective (39-44%), that infected grubs consumed the same amount of roots as uninfected grubs, and that lower grub populations could not be linked to infection. Researchers concluded that earlier reports of success were limited to very high infestations of grubs where other stresses may have increased their susceptibility to diseases".
This is quoted from:
http://www.biocontrol.entomolo...
