Hello All

I am presently working on some beekeeping lectures, and am attempting to
draw together information on the analysis of infestation by varroa by
counting the mites which fall to the sticky board through natural causes,
and using tables to determine if the treatment threshold is reached.

Steve Martin, who issued a Varroa Calculator in the UK, has issued the
following table to convert fallen varroa into an estimate of the number of
mites in the hive, by multiplying the fallen varroa by the multiplier.

Month        Multiplier

JAN             400
FEB             400
MAR             100*
APR             100*
MAY              30
JUN              30
JUL              30
AUG              30
SEP             100*
OCT             100*
NOV             400
DEC             400

The figures asterisked are somewhat imprecise due to the colony and mite
number expanding and contracting rapidly.

Thus if a daily mite fall of 100 mites were counted in June the estimate of
the total mites would be in the region of 3000.

The problem with which I need help is as follows:

Investigations carried out in the UK showed, that if there are more than
2500 mites in the colony that immediate treatment is required. But I have
data from the Swiss Bee Research to say that if more than 30 mites fall per
day that the colony is heading for trouble. This would mean that if the
above table be used that 900 mites would be the threshold in June.

Perhaps this difference is explained by differences in climate between the
UK and Switzerland or perhaps there is some other explanation, eg both
figures are incorrect.

It would appear essential that if non acaricide treatments are used that
some reliable data must be available to determine if the colony is headed
for the threshold to find out if the treatments are working. It would also
seem important to know this data, to establish if an acaricide treatment is
now dealing with resistant mites.

As always any help will be most appreciated.

Sincerely
Tom Barrett
Dublin
Ireland