- M Allsopp
- Plant Protection Research Institute, Agricultural Research Council, Private Bag x5017, Stellenbosch 7599
- 1999
The recent discovery of the parasitic mite of honeybees, Varroa jacobsoni, in South Africa, poses a considerable threat to beekeeping and agriculture dependent on bees for commercial pollination. It is almost certain that the mite will spread into all honeybee colonies in South Africa. If it effects the scale of honeybee mortality witnessed in other parts of the world, comprehensive counter-measures will be needed to ensure the survival of the beekeeping industry, as well as crops such as litchis which require honeybees for pollination.
Summary:
The parasitic mite Varroa jacobsoni was first discovered in South Africa in August 1997 and presents a significant threat to beekeeping and agriculture dependent on honeybee pollination.
The mite is expected to spread to all honeybee colonies in South Africa, likely within three years, affecting both commercial and wild colonies.
Varroa mite has caused massive honeybee colony mortality worldwide, especially in Europe and the USA, where beekeeping relies heavily on anti-varroa treatments.
African honeybees were initially thought to tolerate varroa due to defensive behaviors and brood biology, but recent data show mite populations as high as elsewhere, disproving this assumption.
Varroa mites feed on bee larva and adult bees, reducing brood development, adult bee longevity, and foraging efficiency, weakening colonies and often resulting in death.
The mite spreads through drifting bees, robbing, swarming, and commercial migration of bees, leading to rapid dissemination.
No completely effective treatment exists; chemical treatments like pyrethroids, amitraz, and others are used with mixed success, and resistance and residues can be issues.
Alternative treatments include thymol, formic acid, lactic acid, oxalic acid, sulfur, and essential oils.
Large-scale honeybee mortality due to varroa in South Africa would severely impact agricultural pollination economically valued at over R2 billion annually.
Wild honeybee population losses will affect biodiversity and indigenous flora reliant on bee pollination.
Beekeepers will need to manage existing stocks more intensively, no longer able to rely on catching wild swarms.
Cooperative efforts between beekeepers, crop producers, and research institutions are essential to address the threat and sustain the industry.
Research is ongoing to monitor varroa effects on honeybees and pollination efficiency in South Africa.
Long-term solutions may include selective breeding of varroa-tolerant honeybees.