Warwick, United Kingdom
July 28, 2008
One of the biggest world wide
threats to honey bees, the varroa mite, could soon be about to
meet its nemesis. Researchers at the
University of Warwick
are examining naturally occurring fungi that kill the varroa
mite. They are also exploring a range of ways to deliver the
killer fungus throughout the hives from bee fungal foot baths to
powder sprays.
It well known that bees world wide are suffering serious
declines and one of the causes of that decline is the varroa
mite, Varroa destructor. Varroa mites feed on the circulatory
fluid of honey bee pupae and adult bees, and in so doing they
activate and transmit diseases which reduce the life expectancy
of the bees and cause the colony to decline. Varroa has had a
major impact in all countries where it has become established,
for example it has caused losses of 30–50% of honey bee colonies
when it first arrived in the UK and is now endemic. The loss of
honey bees on this scale is affecting the pollination of
commercial crops and wild plants. It originates in Asia, but has
extended its range world-wide
At present, the management of varroa is based on the use of
chemical pesticides, but the mites are developing resistance.
Biological control technologies (the use of one organism to
control another) could offer a way of moving pest management
strategies away from a reliance on these synthetic pesticides
but no natural insect or other enemies of varroa species have
been identified on the varroa or on their bee hosts.
Now Defra-funded studies by researchers at the University of Warwick’s
plant research group Warwick HRI, and Rothamsted Research has
found some new natural enemies of varroa from other hosts.
University of Warwick researcher Dr Dave Chandler said:
"We examined 50 different types of fungi that afflict other
insects (known as entomopathogenic fungi) to see if they would
kill varroa. We needed to find fungi that were effective killers
of varroa, had a low impact on the bees, and worked in the warm
and dry conditions typically found in bee hives. Of the original
50 fungi we are now focusing on four that best match those three
requirements."
The team now hope to secure additional funding to further
examine the effectiveness of these four fungi and to begin to
consider the best ways of applying this weapon across the hive.
A number of approaches are being considered including having
fungal footbaths at the main entrances to hives. However the
complex environment within bee hives means that more devious
means of application may be needed.
Dr Chandler will be hosting the Society for Invertebrate
Pathology international conference at the University of Warwick,
starting 4th August, where a special session is being held on
honey bee health. The session will bring together some the
world’s leading experts in bee colony collapse disorder to
discuss the full range of its possible underlying causes. |
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