El may. 23, 2017 10:31, "Jose Villa" escribió:

>In the early days of varroa mites, at least in the southern U.S.,
immigration of mites into treated colonies did not appear to be a problem.

>Where did those mites go?  What has changed to make mite bombs so
devastating, or have they always been like that and we were not aware of
them?

After seing the varroa data I have gathered at Perú in an isolated farm
5x10 km big, growing from 800 to 4000 colonies in one year I conclude that
varroa acumulates over time. Much is diluted in the nucs , so when
monitoring on a monthly base you notice a small but steady build up that if
left un attended will explode after a year .

Most probably that is the answer to those questions. Varroa builded up till
conquering each colony till the present time when those un attended make
for mite bombs.
 Only a concerted effort for treatment on a continental base will drive us
back in time.
No longer can we imagine beekeeping on an apiary or yard base. No apiary is
an island.

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