Maltese Beekeeping Site
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Maltese Bee Diseases |
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Varroa
jacobsonii
Introduction
& Distribution of Varroa in Malta
Acarapis woodi
American
Foul Brood
Chalkbrood Disease
European Foul Brood
Other Disease
Varroa
jacobsonii
Several Sectors within the Agriculture
industry namely, citrus production, suffered a major setback as a
consequence of the outbreak of varroa which wrought havoc among the
local bee population and for which no cure was available.
In just over four months, from Spring 1992 to Autumn , the disease varroasis had destroyed 80% of the bee population, 5000 colonies of anything up to 150,000 bees in each, depending on the season . The immediate effect on the agriculture sector was a poor yield of fruit and vegetables. Honey production is only of minor benefit bees give, compared to their essential contribution in the process of pollination. 25 to 30 tons of honey are produced locally each year from mid-February to end April; and the wild thyme season, from mid-May to the end of June.
The spread of the disease proved impossible to halt its advance and the disease has caused massive damage abroad. Malta's climatic conditions did nothing to help keep the disease at bay, with the high temperatures encouraging the reproduction of the mite.
In Malta, just a few weeks after the disease was diagnosed, the government ordered the necessary medicaments for controlling the disease. Here, the government took all the considerations to be sure that these medicaments, ie. Bayvarol strips, will not leave any residues either in beewax or in honey.
In the year 1992, law enforcement took a new turn and further measurements were considered to control infected imports. Other plans include the registration of colonies, and restrictions on migratory beekeeping.
Introduction & Distribution of varroa in Malta
Since Malta is an island, it should be difficult for the bees to cross over seas. This distance prevented the disease from entering for many years, even when many countries including those in the Mediterranean were infected.
Conclusions of information collected from local
beekeepers showed that the mite was first diagnosed in Gozo and Comino
(two sister islands of Malta). The mite was then easily spread to the
north of Malta, where in few weeks' time, Malta was totally infested
with the parasite. Varroa gradually invaded Maltese apiaries. Mellieha
was one of the first north counrties invaded, and from statistics one
can find that Melleha followed by Mgarr apiaries had the highest
mortality rate caused by the Varroa mite. Then it invaded the center of
the Island including Attard, Zebbug, Qormi and the surrounding areas.
The mite was also diagnosed in the southern part, including Zabbar and
B'Bugia.
Migratory beekeeping was not the cause of contamination in Malta. Varroa was introduced through different sources, like with a swarm of bees on a merchant ship, or else with imported queens or other insects of the class hymenoptera. Adding to these, is the suspicion that the mite may have been introduced with the Bumble Bee which is widely used in Malta for pollination of greenhouses. Since this insect is very hairy, it is a good carrier of the mite, because theparasite can easily grip and get hold to the body of the insect.
Although the disease was not easily introduced in Malta, the spread of the infection was quite rapid. Tge short distances between colonies helped the mite to infest the island quickly and effectively. Within about four months 80% of the colonies had been totally destroyed. Apart from the short distance between the apiaries, our climate is ideal for the mite to live in and reproduce at a fast rate.
Beekeeping practices and systems have encouraged the rapid infestation of the colonies in Malta. Beekeepers have traditionally kept their bees in earthenware jars, where they are not given any specific attention. The only intervention from the part of the beekeeper consisted in the operation of harvesting the honey.
Unfortunately the varroa parasite in Malta will not be totally eradicated, but by taking the preventive measures, the infection can be kept to a minimum and controllable.
Acarapis woodi has not been seen yet
in the Maltese colonies. Several students collected samples and
diagnosed them in laboratories, but no one found any sign of this
disease.
Before Varroa jacobsonii was detected in Malta, American foulbrood was the most serious bee disease. In our country there are no specific statistics dealing with infected colonies by AFB.
There are no strains of bees immune to AFB. However, different degrees of resistance to the disease have been shown. In Malta, the hives infected by AFB are preferably burnt as a precaution against. Presently the Government is offering a 'dip' service to all beekeepers who had the colonies infested. This 'dip' system allows the beekeeper to retain the hive bodies, bottom boards, and inner and outer cover, and burn only the frames. The box hive will be fully immersed in a dip tank filled with paraffin wax and the high temperatures reached by the wax will sterilise the box.
In Malta there are no statistics stating whether there are any signs of the diseases. Although some beekeepers admit that they detected EFB in their apiaries.
Chalkbrood disease is not a serious problem in our Island, but beekeepers report lack of activity in the colony caused by this disease. Practically no medication is applied to control this disease, since it diminishes as the spring and summer temperatures increase.
Malta as an Island has its advantages and disadvantages. It has an advantage because, since migratory beekeeping is practised within our shores, no introduction of diseases can be introduction from abroad. On the other hand since Malta is small if an infestation is introduced, in a couple of days this is widespread throughout the Island. This took place in 1992 with the introduction of Varroa jacobsonii. Diseased bees foraging out, come in contact with clean bees. Through contacts, parasites or infections overpass from one insect to another. On returning to its own hive the newly infected bee will infect all the colony.
There are many other diseases other than those mentioned that attack the honey bee; Stonebrood, Amoeba disease, Sacbrood and Bee Paralysis disease, but none of which were diagnosed or documented in Malta.
