There seems to be an epidemic of "disappearing bees" here in southeast
Pennsylvania.  Within the last couple of weeks at least seven beekeeping
friends have contacted me and told me the same sad story: strong
colonies--some had produced surpluses of 100lb or more--had suddenly
disappeared after the harvest.  Some reported strong colonies had vanished
within two days!
     Some of these beekeepers also reported  observing large numbers of
yellow jackets "robbing"  the deserted hives.
     Some additional observations which may be relevant are:
     (1) Varroa mites were found on surviving larva in colonies that were
checked.
     (2)Yellow jacket colonies were noticeably late becoming established
following a harsh winter.  But at least one exterminator noticed that these
late-established colonies were unusually large.
     (3) In one case "hundreds" of yellow jackets were reported to be
killing bees and robbing.  The others reported that the missing bees were
not piled dead in front of the hive entrance as would be expected if the
colony demise was due to pesticide poisoning or robbing.  They are just
gone!
     It was suggested via BEE-L last week that the bees pressured by the
presence of varroa mites abscond to another hive.  But no one here has found
colonies in their beeyards with suddenly increased population.
     Others have suggested that the mites are a vector for a bacterial
disease of the adult bees as well as of one for the brood.  But how does
this account for the sudden disappearance of the adult bees (within two
days!)?
     So for me it remains a mystery--a fascinating one, but a tragic one;
some of my friends have had their colonies wiped out overnight.
     My wife and I found varroa in our thirteen colonies this year.  They
produced well--over 1200lb.  We treated using Apsitan strips after
harvesting the crop in late August.  It was mild yesterday afternoon after a
killing frost last week.  Our colonies all had lots of healthy entrance
activity, even some pollen carriers--unusual here for late October.  No
yellow jackets in sight.  No deserted hives--yet.
 
Robert Hawkes
West Chester, Pennsylvania
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