Honeybee pests and diseases

Beekeeping
Honeybee pests and diseases
	The parasitic mite Varroa destructor The most serious parasite of honeybees in the 20th century has undoubtedly been the ectoparasitic mite, Varroa destructor (formerly Varroa jacobsoni). Relatively harmless on its natural host, the Eastern honeybee, Apis cerana, the varroa mite has 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 not a benign pest, resulting in most cases in the death of the parasitised 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 and commercial beekeeping is only possible with the liberal use of anti-varroa pesticides.  (Read more...)
	Information on other pests and diseases Keeping beekeepers and crop producers informed about honeybee pests and diseases is important to create better products and services. Other organisms that are of little economic importance are: Small hive beetle, banded bee pirate, yellow bee pirate, various large hive beetles, parasitic flies, other parasitic mites, other wasps, the Deathshead moth, greater and lesser waxmoth, honeybadgers (ratels), nectar flies, rodents, toads, geckos and lizards, starvation, overheating and chilling, termites, ants, bee scorpions (chalifers), braula (bee louse), and birds. South Africa is still free of American Foulbrood and the parasitic mite, Tropilealaps clarea.
	Amoeba Disease This disease of the digestive system of adult honeybees is caused by the protozoan Malpighamoeba mellificae. After ingestion, the cysts of the amoebae germinate and migrate to the Malpighian tubules. After 18 days, the amoebae, after consuming many epithelial cells, form cysts that are soon after liberated from the tubules and then voided.  (Read more...)
	Chalkbrood The occurrence of chalkbrood in South Africa has dramatically increased since the discovery of the parasitic varroa mite. The fungus Ascosphaera apis that causes chalkbrood only attacks larvae. When the spores are ingested, they germinate and mycelia grow through the body penetrating the epidermis and covering the pre-pupa in a short time-span. Spores can also germinate when it lands on the cuticle and penetrate the pre-pupa from the outside.  (Read more...)
	European Foulbrood This is the most widespread and common brood disease in South Africa. It is not considered to be serious, but in combination with other maladies it may play a significant role in the collapse of a colony. It is caused by the bacterium Melissococcus pluton (formally known as Bacillus pluton and Steptococcus pluton) and mostly affects young unsealed larvae. The bacterium is spread through food transfer from adult to young larva. It is suspected that the bacterium is present in most colonies, but in latent form, not appearing unless stress factors favour an outbreak. The remains of dead larvae are a source of further infection. Viable spores may also be present on the wax and other debris on the bottom of the hive, on the comb, or present in feces of nurse bees.  (Read more...)
	Nosema Nosema occurs in adult bees and is caused by a one celled organism, Nosema apis. Spores of nosema are ingested with the food and germinate in the midgut of the bee. Each sends out a long thread, known as the polar filament, which penetrates the cells lining the gut. The living 'germ' of the spore passes through this filament and into a gut cell. Here the organism multiplies and soon fills the infected cells with spores.  (Read more...)
	Tracheal Mites The tracheal mite, Acarapis woodi, causes what is generally referred too as Acarine disease. The adult mites infest the prothoracic tracheae i.e. the first pair found on the thorax, and complete their life cycle there. They feed on the blood (haemolymph) by piercing with their mouthparts through the tracheal walls.  (Read more...)
	Viruses Sacbrood (designated SBV) is probably the best known viral disease because of its well-recognisable symptoms. In the pre-pupa stage, just prior to the cells being capped, when the larvae are in the stretched or upright position infected larvae die. The cell cappings over dead larvae are often perforated and sunken.  (Read more...)