Agriculture Reference
In-Depth Information
Research is showing that the
pathogenic fungus
,
Matarhizium anisopliae
, may also be
effective in the biological control of varroa - at least, as effective as fluvalinate.
Parasitic mite syndrome (PMS)
I have included this syndrome because of its association with varroa. 'Parasitic mite
syndrome' (PMS) is the name given to a range of abnormal brood symptoms associated
with the presence of varroa in both brood and adult bees. The symptoms, which were
first noticed by beekeepers and the US Department of Agriculture Bee Research
Laboratory in the mid-1990s, were found in association with infections of both varroa
and acarine (the tracheal mite) (see above).
It is suggested that PMS could be caused by the varroa mite vectoring the acute bee
paralysis virus (ABPV), and possibly other viruses, into the honey-bee larvae. However,
in one piece of research, US scientists analysed samples of adult bees from colonies with
PMS and found that in the majority of cases, neither ABV, Kashmir bee virus (KBV)
nor any of nine other bee viruses were in evidence. Therefore, while these viruses may
be one of the causes of the syndrome, other factors cannot be ruled out.
PMS affects both brood and adult bees and is usually associated with colony collapse,
especially in the autumn. The symptoms can appear at any time of the year, although
they are more prevalent in mid-summer and autumn. These symptoms are, however,
often difficult to interpret and can be very easily confused with the symptoms of AFB,
EFB, sacbrood and various viral diseases (see Photograph 14 in the colour photograph
section of this topic). Because commercially available, easy-to-use tests for AFB and
EFB can now be purchased, the first thing to do is to test for AFB/EFB and other
problems. One way of differentiating the symptoms of PMS from AFB is the lack of a
foul smell. Similarly, if the larvae have dried to scales, these can be removed easily, and
they will not rope if a stick is pushed into the cell and slowly extracted.
Identifying PMS
Once other problems have been eliminated, look for all or some of the following
symptoms (the notes in brackets indicate symptoms similar to other diseases and
problems):
