I mentioned that i had lost 2 nucs & 2 single deep hives awhile back. I sent the corpses to the usda lab. the 2 nucs & a single deep all with solid bottom boards had 25, 18, & 15 mites per 100. the single deep with a scb had 2 mites per 100. not exactly a clinical study but interesting nonetheless. I treated most hives last august but not the nuc. I guess i'm going to have to get more aggressive with my mite treatments.