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The Ecological Threat of the Varroa Mite Varroa jacobsoni In South Africa
By Mike Allsopp
Honeybees Programme Manager, Plant Protection Research Institute, Agricultural Research Council, South Africa.
 The most serious pest or disease of honeybees in the 20th century has undoubtedly been the ectoparasitic mite,
Varroa jacobsoni. Relatively harmless on its natural host, the Eastern honeybee
Apis cerana, the varroa mite has recently crossed onto the Western honeybee
Apis mellifera and spread from its Asian origins throughout most of the world. On the commercially important
Apis mellifera the varroa mite is no longer a relatively benign pest, resulting in almost all cases in the death of the honeybee colony. In regions of the world where the
varroa mite is well established, such as Europe and the USA, wild honeybee populations have all but disappeared as a result of
varroa mortality. As an example, it has been reported that in California the
varroa mite eliminated 99% of all wild honeybee colonies within two years of its arrival. In these countries, practically the only honeybee colonies remaining are colonies maintained by commercial beekeepers, and kept alive by means of anti-varroa treatments, normally pesticides.
It will never be known how the varroa mite got to South Africa, but can be safely concluded that it could have entered only through the illegal importation of honeybee colonies or queens, or accidentally from a honeybee swarm on a ship or container. The second explanation seems more likely as, during the first survey for the mite in the country immediately after its detection, the greatest concentration of mite was very close to Cape Town docks.
MtDNA from samples of varroa collected in South Africa have been analysed by both the USDA (Baton Rouge) and CSIRO (Australia) and have determined that the immediate origin of the
varroa in South Africa as Europe. The varroa in South Africa fall into the Korea mitotype of
Varroa jacobsoni, which has recently been re-named Varroa destructor. As the name implies, this is the population of mite that has been responsible for the extreme effects seen in Europe and the USA.
The varroa mite was first found in South Africa in August 1997 and has subsequently spread over most of the country; at present it is not found elsewhere in sub-saharan Africa. It can be reliably predicted that the mite will be present in all honeybee colonies in South Africa within 2-3 years, and thereafter will spread through the honeybee colonies of our neighbouring countries. Mite infestation levels are continuing to rise in infected colonies although as yet only a few honeybee colonies can be reliably reported to have succumbed to the mite. This does not mean, however, that the bees of Africa are definitely going to be tolerant to the
varroa mite, although there are a number of good reasons to believe that this might be the case. In a number of regions of the world, it has taken as much as 7 years after the arrival of the mite for honeybee population to crash.
At present, therefore, it remains to be determined what effect the mite will have on honeybee populations of Africa. The effect could be negligible or it could be catastrophic, only time will tell. The possible threat has, however, been considered to be sufficient to establish a
Varroa Working Group of interested stakeholders including the National Department of Agriculture, the National Department of Environmental Affairs and Tourism, the National Parks Board, the Deciduous Fruit Producers Trust, the Sub-Tropical Fruit Producers, SANSOR and the Federation of South African Beekeepers, and to institute a
Varroa Research Programme to be conducted by ARC-PPRI. At stake is the livelihood of the commercial beekeepers of South Africa as well as the value-added to commercial crop production by honeybees, which has recently been estimated to be in the order of R3.2 Billion per annum. It is also worth noting that this agricultural output sustains some 250 000 jobs.
As overwhelming as the above figures are, in terms of the possible effect on the economy of South Africa of honeybee colony collapse due to
varroa mites, the true threat of the varroa mite is not to beekeepers nor to commercial crop production. Commercial honeybee colonies will be able to be maintained even if
varroa proves to be lethal in South Africa, by the judicious use of varroacide chemicals. Hence, commercial crop production will also be sustained albeit with greater expense and difficulty. What will not be able to be sustained should
varroa prove to be lethal is the pollination provided by honeybees to the indigenous flora of South Africa. Wild honeybee colonies are beyond the reach of chemical treatment, and should
varroa prove to be lethal in South Africa, the wild honeybee population will disappear, as has been the case in both Europe and the USA.
The possible ecological consequences of such an event are alarming. The loss of honeybee colonies in the USA was of no great environmental concern as honeybees are exotic to the Americas. Similarly, in Europe there are far more honeybee colonies by virtue of commercial beekeeping than would naturally be the case, and hence the loss of the wild honeybees has had limited significance. In Africa, and particularly in the more remote parts of Africa, the overwhelming majority of honeybees are wild bee colonies, which could potential die as a result of
varroa infestation. There is no accurate determination, nor even an accurate estimation, of the importance of honeybees in the pollination of the indigenous flora. Estimates vary considerably but a conservative estimate is that honeybees are the dominant pollinators of as many as 60% of indigenous flowering plant species in Africa.
Should the honeybee population be lost due to varroa, the spectre of massive ecological damage including the possible loss of plant species due to the lack of adequate pollination is not inconceivable, with possible consequent loss of animal species. The real threat of the
varroa mite in Africa is to floral conservation and biodiversity, and to all that means from aesthetic, environmental and tourism. Should the
varroa mite prove to be lethal and to begin to eliminate wild honeybee populations, there is relatively little that conservation authorities will be able to do. Conservation authorities may perhaps be forced to become beekeepers, keeping bees in a managed manner allowing for the treatment with varroacides, to sustain the pollination of their plant species. This, of course, could only be an emergency measure, and the long-term solution to the possible
varroa problem will come from a better understanding of the mite in African honeybees, and the development of honeybee populations that are naturally tolerant to the
varroa mite. In this vein, continued and substantial support for the Varroa Research Programme is surely essential, even if at present it is not known if the
varroa mite will present a massive environmental risk to Africa. The risk is simply too great to ignore.
One element of the Varroa Research Programme that requires an immediate and substantial contribution from the environmental and conservation authorities of South Africa is to determine the effect that the mite is having on wild honeybee populations. Only by monitoring the arrival of the mite into honeybee colonies in the conservation areas of South Africa, and by determining the effect of the mite on these colonies, will it be possible to determine the true threat of
varroa to the floral conservation and biodiversity in these conservation areas. This monitoring obviously has to begin before the arrival of the mite in these regions, hence the urgency of this research element. It is recommended that a systematic honeybee and
varroa mite monitoring programme be established as soon as possible in as many conservation regions of South Africa as is possible, and that a workshop be held to train conservation officials on how to proceed with this monitoring programme. Only such a programme will be able to determine the true ecological threat of the
varroa mite in South Africa.
Editorial Comment by Garth Cambray, Makana iQhilika Meadery/Rhodes University
Dept. Biotechnology
As a beekeeper and biotechnologist operating a company which has a beekeeping
aspect, I am able to appreciate what Mike has written first hand. In our region
of the Eastern Cape, where game farming is now the dominant agricultural
activity, the wild honeybee population is important, adding protein to animal
diets through the pollination of berry producing plants. Without these berries,
the diets of animals such as baboons, kudu, vervet monkeys, bushpigs and many
others will be seriously altered. In addition, honey gathering by Xhosa
inhabitants of these farms, an important part of producing the ancient beverage
iqhilika, is failing. We have been contacted by honey gatherers and beekeepers
alike in the last two weeks, all reporting the failure of beehives. Through the
application of appropriate technology, we have been able to prevent the collapse
of our beehives both in commercial beehives and a select few wild swarms.
The following are some links which are of use to those concerned about varroa
(list prepared by Science in Africa):
A simple biological control involving the removal of drone frames where varroa
prefers to reside. Note that in many parts of South Africa an actual market
exists for drone comb, especially among Xhosa and Tswana speaking peoples.
www.xs4all.nl/~jtemp/dronemethod.html
A number of chemical control methods exist for varroa. The following is a list
of a few that we have either tested, or seen being used at Makana Meadery:
For many years the workhorse varroa medication, Apistan is a highly
effective varroa treatment. Resistance has developed to this product in the US,
parts of Europe and Canada as a result of misuse. If beekeepers resort to this
treatment in South Africa, we hope that misuse will not be prevalent.
www.apistan.com
Formic acid has been used by many around the world as a varroa treatment. At
Makana Meadery we have been using it to control varroa populations with
reasonable success. It is a difficult treatment to work with, but once mastered,
is reasonably effective. For more information on a low cost method for preparing
it, contact garth@iqhilika.co.za. The
following pages listed below give details of various methods used in Europe and
Canada.
http://www.swienty.com/engelsk/varroa.html
www.internode.net/honeybee/Formic/Default.htm
We have also included this link to the Bayer homepage. Bayvarol, an effective,
but slightly expensive medication for treatment of varroa is in the process of
being withdrawn from the South African market (Personal communication with Bayer
Animal Products). This is due to low demand and the fact that beekeepers are
making use of many other organic treatments. We would however urge anyone who feels it
would be useful to still have this medication to contact Bayer of South Africa
through the contacts listed below.
http://www.bayer.co.za/contacts.html
For more information contact Garth Cambray garth@iqhilika.co.za
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