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VARROA MITE
The Varroa mite, Varroa destructor, is the most serious threat to the western honeybee, Apis mellifera. Varroa is a parasite that feeds on the bee and spreads viruses. Untreated, colonies die in a few years.
Monitoring mite fall with varroa floorsgives early warning of dangerous varroainfestation. In Europe, calculate the mitepopulation from natural mite fall:multiply daily mite drop by 250–500when no brood or 20–40 when broodis present. (Martin, 1998).
Female varroa lay their eggs in brood cells,especially drone brood cells. They feed o�developing bees and impair normal growth.
Varroa spread viruses and amplify their e�ects.Deformed Wing Virus (DWV) is a typical signof Varroa infestation. Other viruses, oncethought insignificant, are also killing bees.
Varroa Impact
Since the early 1900s varroa has spread throughout the world. By 2016, Australia, one of very few countries that appeared to be varroa-free, seemed under threat..
Varroa populations keep growing at the end of the season even as thehoneybee population declines. So treatment at the end of the honey flow and before winter preparations is essential.
Varroa mites attach themselves toflying bees and spread with robberbees, drifting bees, swarms andmigratory beekeeping. Varroa infiltrate colonies by mimicking thescents of bees. They even know when colony collapse is imminent and leave with the absconding beesto infest another colony.
Treatment, IPM and resistance
Varroa cannot be eliminated, but numbers can be controlledusing e�ective and approved treatments that are safe for bees, honey, humans and the environment. Overuse of single treatments accelerates resistance, so alternating treatments with Integrated Pest Management (IPM) is essential.
J F M A M J J A S O N D
40,000
30,000
20,000
10,000
0
10,000
5,000
0
6 Mitesper
100 Bees
35 Mitesper
100 Bees
BEES MITES
Apiary spread
1904
le
aves
Java
as
Varro
a
ja
cobs
oni
1960
s d
iscov
ered
in U
SSR
1970
s d
iscov
ered
in E
urop
e
1980
s fi
rst g
ener
atio
n
tr
eatm
ents
eg
Apist
an
1987
d
iscov
ered
in U
SA
1992
d
iscov
ered
in B
ritai
n
1996
ro
le o
f viru
ses
in V
arro
a
im
pact
real
ised
1990
s s
econ
d ge
nera
tion
trea
tmen
ts e
g Ap
igua
rd
1990
s P
aras
itic
Mite
Syn
drom
e
term
coi
ned
2000
Va
rroa
dest
ruct
or
re
cogn
ised
as d
i�er
ent
spe
cies
to V
arro
a
ja
cobs
oni
2000
disc
over
ed in
New
Zea
land
2000s 1980s 1970s 1960s 1950s First detection
Spread of the Varroa mite, in selected counties over a series of decades
1972 Brazil
1977 Germany
1959 China
1961 India
1904 Indonesia
No reports No information
1987 USA and Canada
2007 Hawaii
2000 New Zealand
Data source: Atter Webster TC, Delaplane KS 2001, Mites of the Honey Bee
Global Spread
Tim
elin
e
