HONEY BEE DISEASE
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Samples of diseased comb were brought to Rothamsted Experimental Station in the UK for examination by Dr Brenda Ball. She verified that the disease is caused by Thai sacbrood virus. strongly suggest that some some university or institute in India undertakes a study of the epidemiology of Thai sacbrood virus. Such a study will be very useful if efforts are being made towards breeding a strain of Apis cerana which is resistant to the disease. However, if am asked for suggestions, shall be happy to provide them if I can.
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Jan Olsson, 15 April 1992
Beekeeper in south India
India The disease is virulent and threatens to wipe out beekeeping in Kerala, Karnataka and Tamil Nadu.
Spreading
This disease was firs reported from Thaila id in
1976 and has been identified only in Api cerana, the asian hive bee. T 1e disease is caused by a different one from t at causing sacbrood dise. ase in the european honey b se Apis mellifera. (Sacbrood in \pis mellifera rarely causes t re death of a colony.} Lit cleis known about Thai sac rood virus or how colonies of Apis cerana would naturally cope with its presence. The Shah Beekeepers in Kashmi recommend removing and destroying all infected brood com: s and repl acing with new fc undation, or creating at reak in br od rearing by aging the queen. 5
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In our area of operation there are 4647 beekeepers with 34 000 bee colonies, and a production of about 17 500 kg of honey. Until now the area was free from any sort of bee disease. But this year the bee colonies of Malnadu area have started dying. The larvae are not growing and ultimately the entire bee colonies die.
We need assistance and guidance in dealing with this disease.
Y Mahabala Bhat, Secretary, The South Kanara Beekeepers’ Co-operative Society Ltd, Dharmasthala, India
Enquiries among many beekeepers indicate that they started losing colonies in November 1991. They assumed it was due to normal incidents of absconding. The last reports (10 March 1992) talk of estimates of 5-10 000 lost colonies in Kerala, “several thousand” in Dakshina Kannada and spreading of the disease into Tamil Nadu. In one location, which visited on 2 February and found disease-free, 1500 colonies were lost later in the month. The mortality of colonies in the affected areas is over 90% |
short-term aspects Considering the speed with which this disease spreads and the very high mortality, we must expect the disease will strike
everywhere within a short time. Thus, no beekeeper may escape. It is a very pathetic tragedy to these poor people, and we suggest that they are given some compensation. Lang term aspects Nature has a way of inflicting disease on living creatures, but never wipes them out completely. A few individuals survive due to freak resistance. Because of lowered competition, they have excellent survival conditions and soon multiply again into a new, resistant stock. There are many cases where this has happened, and the time gap between the wiping out of the old population and the appearance of a new one depends on many factors. We suggest the following plan of action: colonies surviving in disease-affected areas must be found and their queens must be preserved at all costs @ a breeding, testing and selection programme must be carried out @ when testing and selection is over, a large number of breeder queens must be produced and distributed @ large nurseries must be established with these breeder queens, and thousands of nucleus colonies, headed by queens of resistant stock, must be produced and
Research into the management of Apis cerana in north India has either not taken place (honey bee researchers tending to be infatuated with the european bee Apis mellifera) or has been unsuccessful. By contrast Apis mellifera has received much research attention. Whatever the cause, beekeeping with Apis cerana in the north is practically at a standstill. The situation is the reverse in south India. Beekeeping with Apis cerana has taken place in a widespread and regular manner for many years, although a large-scale industry like that created in China during the last four decades is not present. This is due to negligence on the part of researchers in taking interest in the subject, as well as lack of government support. Thus beekeeping has remained a widespread, but small-scale village industry. The lack of large-scale beekeeping with Apis cerana in south India is because of management problems which all led to the same result: Apis cerana absconded, and beekeepers found themselves without bees. Our work since 1980 found a solution to these problems. These include the maintenance of strong colonies, annual removal of old brood comb and supplying sugar syrup to ensure that bees have adequate provisions. By applying these new methods, beekeepers achieved success in their work, and hundreds of rural poor have taken up large-scale, Apis cerana beekeeping. They obtain average yields of 20 kg per colony year after year, producing several tonnes of honey in each apiary. The largest is Honey Valley Apiary in Coorg. The beekeeper produced 6000 kg in 1991 from 300 colonies. Some of those colonies yield over 40 kg. As far as we know he is now the largest, single honey producer in India. Jan Olsson, Frederiksvej 52/2, DK 2000, Frederiksberg, Denmark
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Symptoms ®
The disease works at lightning speed. Within 10-12 days after infection, brood mortality approaches 100%.
The larvae die in the third, fourth and fifth moult. ® There is no discoloration of the dead larvae for many days They remain pearly white, turning to a light yellow as they begin to dry up ® The diseased larvae stretch and twist in their cells, and finally collapse flatly on the lower cell wall @ There is no smell ® The fina! mystery: a distinct, very characteristic black spot, 0.5-1.0 mm appears in the anterior end of the ®
larva.
