Börje Svensson, Sala, Sweden
Reproduced with kind permission from
Bees for Development Journal 71 (June 2004)
© Bees for Development www.beesfordevelopment.org
Individual bees are very delicate organisms existing within the strong and
resistant body of their colony, inside its carefully protected cavity.
Honeybees have been surviving this way since long before man first stepped
on
earth (Free et al., 1982). An individual bee will freeze to death within
minutes in the climate of Sweden where I have been keeping bees for 28
years.
Colonies of bees have survived my mismanagement, infestation with wax moth,
queenlessness, wet insulation, or even being tipped over during a cold
winter
storm. Some of my colonies always survived and managed to multiply when the
spring sun shone and brought flowers and nutritious food back into the life
cycle again. Winter losses never ever exceeded 15% - until last year.
Unwelcome experience
Winter 2002-2003 was a totally new experience for me and for thousands of my
colleagues in countries like Austria, Belgium, Denmark, Finland and Germany.
I lost 50 colonies out of 70! Only 20 survived. One neighbour lost 95 out of
120, someone else 24 of 25 and so on.
Some colonies died even in December. I found colonies that had just stopped
living. They had given up life without any sign of struggle. They were dead
without visible reason. They had plenty of good sugar feed. Pollen stores
were available. The queen was sitting dead in the middle of the cluster.
Other colonies tried to survive but gradually dwindled away with less and
less bees and finally gave up before the warm weather could help them to
recover.
I had a terrible job to clean up all the dirty comb and contaminated hives.
The combs had to be brushed off before being melted in water so that the
sugar remains could be separated from the pure wax. It is always a
depressing
job disposing of dead bees knowing their important task for maintaining good
pollination in our neighbourhood.
Immediate survey
Our National Beekeepers’ Federation, SBR, reacted without delay and
organised
an instant survey within a random sample of 2,520 beekeepers (Kristiansen,
2003). From the 1,654 responses we can conclude that the colony losses in my
county were about 36%. The national average was ‘only’ 20%.
A similar survey of 6,072 German beekeepers came up with an average of 29%
winter losses during the same winter (Otten, 2003). The Swedish survey could
not make any conclusions about any particular cause of the winter deaths but
rather speculated that the event was a combination of unfavourable
circumstances during the season 2002.
However there are several observations that can rule out some of the
theories
proposed:
1. Both experienced and less experienced beekeepers had problems.
2. The death toll was high also in areas where the Varroa parasite has not
yet arrived.
3. The death toll was high also in areas where other diseases such as
foulbrood, sacbrood, chalkbrood or nosema are rarely seen.
4. The death toll was high also for colonies in very well insulated hives.
5. The winter death was very low in the forest areas of northern Sweden but
at the same time very high in the farmland area in northern Finland.
6. The death toll was high both in areas affected by the radioactive
Cesium137 downfall from the Chernobyl accident as well as in non-affected
areas.
More bad news
So we are many beekeepers who have hoped until now that the scientists are
correct: that it was an extremely bad year of a kind that appears once in a
while. But is it really like that? The sun is now warming up the hive
bodies
and the snow is rapidly melting away. The first Crocus flowers are beginning
to provide pollen and Salix will soon follow. A first summary of my
remaining
colonies is again a catastrophe!!! Only 17 colonies surviving out of 30!!!
And some of the survivors are very weak and may not make it another 2-3
weeks. My phone is ringing. Beekeeper friends are reporting: 7 of 8 dead,
all but 2 dead, more than 50% dead and so on. It is too early to see if this
is as serious a problem as last year, but this time I am not going to wait
before raising my voice.
Possible explanations
We have to find resources and support to find out what is happening to our
bee environment. What are the possible explanations? How can researchers
join
hands to determine how to overcome these problems? To start the discussion I
would like to present a list of possible explanations that can be thinned
out
or extended with contributions by those who have a better view. Please join
the debate with your own observations or theories.
1. The European Commission has decided to allow use of a number of doubtful
pesticides. Some of these were banned in Sweden for many years such as
Amitrole, 2,4-D, Linuron, Mecoprop, Paraquat, Propineb, Thiram and
Bromoxynil. Many of these are extremely hazardous to humans but the
objections from our government chemistry authority had no effect on the
decision makers in Brussels. These pesticides are mainly herbicides and
fungicides and most likely we will not find one of them that is used all
over
the affected region.
2. The European Commission has authorised a large number of new pesticides
for an even larger number of different uses without adequate hazard testing.
The new generation of pesticides can be generalised as: i) low dosage, ii)
long persistence, iii) systemic action, iv) difficult to detect in
laboratory
tests. The Swedish government authority is also complaining in their annual
report (KI, 2003) that it is difficult to keep track of the different
pesticides due to many changes of ownership within the private sector.
3. The aphid pests (Megilethes spp) on oil-seed rape have developed
resistance to the most popular pyrethroid pesticides. Therefore the
chemistry
authority again approved use of the extremely bee poisonous insecticide
Fenitrothion (Sumithion or Folithion) from year 2001. This pesticide was
banned more than 20 years ago due to its enormous risks for bees, other
insects and aquatic life.
4. The use of insecticides increased in Sweden 2001-2002 by 250%. A possible
reason is that the warm summers (global warming?) caused heavy growth of
aphid colonies in many grain crops.
5. A new range of pesticides has entered the market during the last five
years. These are all based on the active ingredient Imidakloprid, a chemical
that affects the digestive neurosystem of insects. Popularly we can say that
insects that come into contact with these products lose their appetite and
stop being harmful to crops. These insecticides have long persistence and a
systemic effect. It is therefore possible that the harmful effect will occur
over a long period and only gradually in a bee colony that is slowly during
winter consuming its stored reserves of plant material. The treated seed
will
for instance germinate in August 2004, the plant will flower in June 2005
and
bees will collect and store contaminated nectar and pollen that can cause
indistinct symptoms during the winter 2006, one and a half years later!
Here is a list of Imidakloprid products being registered in Sweden:
- Chinook for seed dressing of oil-seed rape seed.
- Gaucho and Montur for seed dressing of sugar beet seed.
- Prestige for dressing of potatoes before planting.
- Confidor for treatment through irrigation water in green houses
(ornamental
plants, tomatoes, cucumber and sweet pepper).
- Merit Forest for treatment of forest plants against insect attacks.
- Some products are also registered for use in homes as dip sticks for
indoor
plants.
Commercial representatives also confirm that these products have been tried
as seed dressing on wheat and oats. They are however not willing to disclose
to what extent farmers are using seed treated with these chemicals. In
France Imidakloprid pesticides have been banned for use on sunflower crops
after heavy protests from beekeeper groups.
6. Pesticides in sugar cultivation or industrial manipulation of white sugar
may be another problem for bee colonies. Use of the above mentioned systemic
seed dressers on sugar beet seed (point 5) or insecticides on sugar cane
fields can be a hidden problem. Also new techniques for extraction or
bleaching of white sugar may cause a possible hazard to bees. An increasing
trade with sugar products has also been noted
7. Extensive use of desiccants (Glyfosat, Rambo, Roundup) for total
extermination of weeds instead of mechanical cultivation. The total usage of
these herbicides has increased four years in a row. This is remarkable since
the increase of Glyfosat products took place at the same time as the acreage
of ecological farming also increased. This must imply that the intensity of
Glyfosat usage has increased on the farmland that is still cultivated with
chemicals. Several Glyfosat products are also registered for use by
gardeners.
8. Increasing downfall from burning of household waste material as an energy
resource. A new government fee on dumping of waste products has created an
enormous interest for using household waste as an important energy resource.
Large municipal heat and power plants have been converted from charcoal and
crude oil to household waste and other biomass sources. The disadvantage
with
this quick change is that the cleaning techniques for many dangerous organic
substances in the smoke are still rudimentary. In some cases we do not even
know what to look for. The amounts of downfall may be very small but still
extremely hazardous to human and other life from the very stable organic
substances that come with the smoke from waste burning. Examples of such
substances are PCB, Toxafen, Dioxin, halogenated flame retardants,
nonylphenol, organic tin compounds, phthalates and secondary residues of all
these products etc.
I do not claim that I have any proof for any of the above theories. What is
of paramount importance is that we try to find out the cause for the winter
deaths of honeybee colonies during the last two years. Will my bees survive
another winter like this?
Or will we meet a silent spring next year?
If bees cannot survive can we?
Börje Svensson, Sala, Sweden (author)
References
Free, J.B. ed. (1982) Honeybee Biology, Central Association of Bee-keepers
Publications, Ashford, UK.
Kemiinspektionen (2003) Sold quantities of pesticides 2002, KI, Stockholm,
Sweden.
Kristiansen, P. (2003) Vinterförlusterna 2002/2003, Bitidningen (7-8),
13-14.
Otten, C. (2003) Daten und Fakten zu den Völkerförlusten, ADIZ 37 (8/2003),
6-8.
STOP PRESS
>From the author – May 2004
We are beginning to see the full size of the problem now. In my county it
seems like more than 50% of colonies died this winter.
The media is beginning to take notice now, but some of the news is old, as
far back as 1999 from France!
http://www.bees-trees.demon.co.uk/news%20and%20views.htm#silent spring
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info ---
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
|
