Diseases of the honeybee
Encyclopedia
Varroa mites
Varroa destructor and Varroa jacobsoni are parasitic mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
s that feed off the bodily fluids of adult, pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
l and larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l bees.
Varroa
Varroa
Varroa is a genus of parasitic mites associated with honey bees, placed in its own family, Varroidae. The genus was named for Marcus Terentius Varro, a Roman scholar who was also a beekeeper.-History and behavior:...
mites can be seen with the naked eye as a small red or brown spot on the bee's thorax.
Varroa are carriers for a virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
that is particularly damaging to the bees.
Bees that are infected with this virus during their development will often have visibly deformed wings
Deformed Wing Virus
Deformed wing virus is an RNA virus, one of 18 known viruses affecting the honey bee, Apis mellifera. The virus was first isolated from a sample of symptomatic honeybees from Japan in the early 1980s and is currently distributed worldwide....
.
Varroa have led to the virtual elimination of feral bee colonies in many areas and is a major problem for kept bees in apiaries
Apiary
An apiary is a place where beehives of honey bees are kept. Traditionally beekeepers paid land rent in honey for the use of small parcels. Some farmers will provide free apiary sites, because they need pollination, and farmers who need many hives often pay for them to be moved to the crops when...
. Some feral populations are now recovering—it appears that they have been naturally selected
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
for Varroa resistance.
Varroa were first discovered in Southeast Asia in about 1904, but is now present on all continents except Australia. Varroa were discovered in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 1987, in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
in 2000, and in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
in 1992 (Devon
Devon
Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...
).
Varroa are generally not a problem for a hive that is growing strongly. When the hive population growth reduced in preparation for winter or due to poor late summer forage the mite population growth can overtake that of the bees and can then destroy the hive. Often a colony will simply abscond (leave as in a swarm, but leaving no population behind) under such conditions.
Varroa in combination with Deformed Wing Virus
Deformed Wing Virus
Deformed wing virus is an RNA virus, one of 18 known viruses affecting the honey bee, Apis mellifera. The virus was first isolated from a sample of symptomatic honeybees from Japan in the early 1980s and is currently distributed worldwide....
and bacteria have been theoretically implicated in Colony Collapse Disorder
Colony Collapse Disorder
Colony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...
.
Treatment
A variety of treatments are currently marketed or practiced to attempt to control Varroa mites. The treatments are generally segregated into chemical controls and "mechanical" controls.Common chemical controls include "hard" chemicals such as fluvalinate
Fluvalinate
Fluvalinate is a synthetic pyrethroid commonly used to control varroa mites in honey bee colonies....
(marketed as Apistan) and coumaphos
Coumaphos
Coumaphos is a non-volatile, fat-soluble phosphorothioate with ectoparasiticide properties: it kills insects and mites. It is well known under manufacturer brand-names as a dip or wash, used on farm and domestic animals to control ticks, mites, flies and fleas...
(marketed as CheckMite) and "soft" chemicals such as thymol
Thymol
Thymol is a natural monoterpene phenol derivative of cymene, C10H14O, isomeric with carvacrol, found in oil of thyme, and extracted from Thymus vulgaris and various other kinds of plants as a white crystalline substance of a pleasant aromatic odor and strong antiseptic properties...
(marketed as ApiLife-VAR and Apiguard), sucrose octanoate esters (marketed as Sucrocide), oxalic acid
Oxalic acid
Oxalic acid is an organic compound with the formula H2C2O4. This colourless solid is a dicarboxylic acid. In terms of acid strength, it is about 3,000 times stronger than acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate , is a chelating agent for metal cations...
and formic acid
Formic acid
Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...
(sold in gel packs "Mite-Away" but also used in other formulations). According to the U.S. Environmental Protection Agency, when used in beehives as directed, these treatments kill a large proportion of the mites while not substantially disrupting bee behavior or life span. Use of chemical controls is generally regulated and varies from country to country. With few exceptions, they are not intended for use during production of marketable honey.
Common "mechanical" controls generally rely on disruption of some aspect of the mites' lifecycle. These controls are generally intended not to eliminate all mites but merely to maintain the infestation at a level which the colony can tolerate. Examples of mechanical controls include drone brood sacrifice (varroa mites are preferentially attracted to the drone brood), powdered sugar dusting (which encourages cleaning behavior and dislodges some mites), screened bottom boards (so that any dislodged mites fall through the bottom and away from the colony), brood interruption and, perhaps, downsizing of the brood cell size. A device called the Varroa Mite Control Entrance (VMCE) is under development as of 2008. The VMCE works in conjunction with a screened bottom board, by dislodging varroa mites from bees as they enter and exit a hive.
Acarine (Tracheal) mites
Acarapis woodiAcarapis woodi
Acarapis woodi is a mite that is an internal parasite of honey bees, originally described from the Isle of Wight. Tracheal mites are related to spiders and have eight legs. Acarapis woodi live and reproduce in the tracheae of the bees...
is a small parasitic mite that infests the airways of the honey bee. The first known infestation of the mites occurred in the British Isles in the early 20th century. First observed on the Isle of Wight
Isle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
in 1904, the mystery illness known as Isle of Wight Disease was not identified as being caused by a parasite until 1921. It quickly spread to the rest of Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
. It was regarded as having wiped out the entire bee population of the British Isles (although later genetic studies have found remnants that did survive) and it dealt a devastating blow to British beekeeping. Brother Adam at the Buckfast Abbey
Buckfast Abbey
Buckfast Abbey forms part of an active Benedictine monastery at Buckfast, near Buckfastleigh, Devon, England. Dedicated to Saint Mary, it was founded in 1018 and run by the Cistercian order from 1147 until it was destroyed under the Dissolution of the Monasteries...
developed a resistant hybrid bee known as the Buckfast bee
Buckfast bee
The Buckfast bee is a honey bee a cross of many species of bees into a stable race developed by "Brother Adam", , who was in charge of beekeeping at Buckfast Abbey, where the bees are still bred today.-Origin:...
, which is now available worldwide to combat acarine disease.
Diagnosis for tracheal mites generally involves the dissection
Dissection
Dissection is usually the process of disassembling and observing something to determine its internal structure and as an aid to discerning the functions and relationships of its components....
and microscopic examination
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
of a sample of bees from the hive.
Acarine mites, formerly known as tracheal mites are believed to have entered the US in 1984, via Mexico.
Mature female acarine mites leave the bee's airway and climb out on a hair of the bee, where they wait until they can transfer to a young bee. Once on the new bee, they will move into the airways and begin laying eggs.
Treatment
Acarine mites are commonly controlled with grease patties (typically made from 1 part vegetable shortening mixed with 3–4 parts powdered sugar) placed on the top bars of the hive. The bees come to eat the sugar and pick up traces of shortening, which disrupts the mite's ability to identify a young bee. Some of the mites waiting to transfer to a new host will remain on the original host. Others will transfer to a random bee—a proportion of which will die of other causes before the mite can reproduce.Menthol
Menthol
Menthol is an organic compound made synthetically or obtained from peppermint or other mint oils. It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. The main form of menthol occurring in nature is -menthol, which is assigned...
, either allowed to vaporize from crystal form or mixed into the grease patties, is also often used to treat acarine mites.
Nosema
Nosema apisNosema apis
Nosema apis is a microsporidian, a small, unicellular parasite that mainly affects honey bees. It causes nosemosis, also called nosema, which is the most widespread of adult honey bee diseases. The dormant stage of Nosema apis is a long lived spore which is resistant to temperature extremes and...
is a microsporidian that invades the intestinal tracts of adult bees and causes nosema disease, also known as nosemosis. Nosema is also associated with Black queen-cell virus.
Nosema is normally only a problem when the bees can not leave the hive to eliminate waste (for example, during an extended cold spell in winter or when the hives are enclosed in a wintering barn). When the bees are unable to void (cleansing flights), they can develop dysentery
Dysentery
Dysentery is an inflammatory disorder of the intestine, especially of the colon, that results in severe diarrhea containing mucus and/or blood in the faeces with fever and abdominal pain. If left untreated, dysentery can be fatal.There are differences between dysentery and normal bloody diarrhoea...
.
Nosema is treated by increasing the ventilation through the hive. Some beekeepers will treat a hive with antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s.
Nosema can also be prevented or minimized by removing much of the honey from the beehive then feeding the bees on sugar water in the late fall. Sugar water made from refined sugar has lower ash content than flower nectar, reducing the risk of dysentery. Refined sugar, however, contains fewer nutrients than natural honey
Honey
Honey is a sweet food made by bees using nectar from flowers. The variety produced by honey bees is the one most commonly referred to and is the type of honey collected by beekeepers and consumed by humans...
which causes some controversy among beekeepers
[Nutrient Database(USDA SR-21)]
In 1996, a similar type of organism to Nosema apis was discovered on the Asian honey bee Apis cerana
Apis cerana
Apis cerana, or the Asiatic honey bee , is a species of honey bee found in southern and southeastern Asia, such as China, India, Japan, Malaysia, Nepal, Bangladesh and Papua New Guinea. This species is the sister species of Apis koschevnikovi, and both are in the same subgenus as the Western honey...
and subsequently named Nosema ceranae
Nosema ceranae
Nosema ceranae is a microsporidian, a small, unicellular parasite that mainly affects Apis cerana, the Asiatic honey bee. It may cause nosemosis, also called nosema...
. This parasite apparently also infects the Western honey bee.
It has been reported that exposure to corn
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
pollen containing genes for Bacillus thuringiensis
Bacillus thuringiensis
Bacillus thuringiensis is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide; alternatively, the Cry toxin may be extracted and used as a pesticide. B...
(Bt) production may weaken the bees' defense against Nosema. In this study, it is stated that in relation to feeding a group of bees with Bt corn pollen and a control group with non-Bt corn pollen, that:
"in the first year the bee colonies happened to be infested with parasites (microsporidia). This infestation led to a reduction in the number of bees and subsequently to reduced broods in the Bt-fed colonies as well as in the colonies fed on Bt-toxin-free pollen. The trial was therefore discontinued at an early stage. This effect was significantly more marked in the Bt-fed colonies. (The significant differences indicate an interaction of toxin and pathogen on the epithelial cells of the honeybee intestine. The underlying mechanism which causes this effect is unknown.)" This study should be interpreted with caution given that there was no repetition of the experiment nor any attempt to find confounding factors. In addition, it is noteworthy that BT toxin and transgenic BT pollen showed no acute toxicity to any of the life stages of the bees examined, even when the BT toxin was fed at concentrations 100 times that found in transgenic BT pollen from maize.
Small hive beetle
Aethina tumida is a small, dark-colored beetle that lives in beehives.Originally from Africa, the first discovery of small hive beetle
Small hive beetle
The small hive beetle is a beekeeping pest.Endemic to sub-Saharan Africa, the small hive beetle, Aethina tumida was first discovered in the United States in 1996 and has now spread to many U.S. states including, Georgia, South Carolina, North Carolina, Pennsylvania, Ohio, Illinois, Minnesota,...
s in the western hemisphere occurred in the US. The first identified specimen was found in St. Lucie, FL in 1998. The next year, a specimen collected from Charleston, SC in 1996 was identified and is believed to be the index case for the United States. By December 1999, small hive beetle was reported in Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
, Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
, Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, and Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, and was found in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
by 2006.
The life cycle of this beetle includes pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
tion in the ground outside of the hive. Controls to prevent ants from climbing into the hive are believed to also be effective against the hive beetle. Several beekeepers are experimenting with the use of diatomaceous earth
Diatomaceous earth
Diatomaceous earth also known as diatomite or kieselgur/kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 1 micrometre to more than 1 millimetre, but typically 10 to...
around the hive as a way to disrupt the beetle's lifecycle. The diatoms abrade the insect's surface, causing them to dehydrate and die.
Several pesticides are currently used against the small hive beetle. The chemical is commonly applied inside the corrugations of a piece of cardboard. Standard corrugations are large enough that a small hive beetle will enter the cardboard through the end but small enough that honey bees can not enter (and thus are kept away from the pesticide). Alternative controls (such as cooking-oil-based bottom board traps) are also becoming available. Also available are beetle eaters that go between the frames that uses cooking oil.
Wax moths
Galleria mellonella (greater wax moths) will not attack the bees directly, but feed on the waxWax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
used by the bees to build their honeycomb
Honeycomb
A honeycomb is a mass of hexagonal waxcells built by honey bees in their nests to contain their larvae and stores of honey and pollen.Beekeepers may remove the entire honeycomb to harvest honey...
.
Their full development to adults requires access to used brood comb or brood cell cleanings—these contain protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
essential for the larvae's development, in the form of brood cocoon
Cocoon
Cocoon may refer to:*Cocoon , a pupal casing made by moth caterpillars and other insect larvae*Apache Cocoon, web development software*Cocoon , a 1985 science fiction film**Cocoon: The Return, 1988 sequel to Cocoon...
s.
The destruction of the comb will spill or contaminate stored honey and may kill bee larvae.
When honey supers are stored for the winter in a mild climate, or in heated storage, the wax moth larvae can destroy portions of the comb, even though they will not fully develop. Damaged comb may be scraped out and will be replaced by the bees. Wax moth larvae and eggs are killed by freezing, so storage in unheated sheds or barns in higher latitudes is the only control necessary.
Because wax moths cannot survive a cold winter, they are usually not a problem for beekeepers in the northern U.S. or Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, unless they survive winter in heated storage, or are brought from the south by purchase or migration of beekeepers. They thrive and spread most rapidly with temperatures above 30 °C (90 °F), so some areas with only occasional days that hot, rarely have a problem with wax moths, unless the colony is already weak due to stress from other factors.
Control and treatment
A strong hive generally needs no treatment to control wax moths; the bees themselves will kill and clean out the moth larvae and webs. Wax moth larvae may fully develop in cell cleanings when such cleanings accumulate thickly where they are not accessible to the bees.Wax moth development in comb is generally not a problem with top bar hives as unused combs are usually left in the hive during the winter.
Since this type of hive is not used in severe wintering conditions, the bees will be able to patrol and inspect the unused comb.
Wax moths can be controlled in stored comb by application of the aizawai variety of Bt (Bacillus thuringiensis) spores via spraying. It is a very effective biological control and has an excellent safety record.
Wax moths can be controlled chemically with paradichlorobenzene (moth crystals or urinal disks). If chemical methods are used, the combs must be well-aired-out for several days before use. The use of naphthalene
Naphthalene
Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...
(mothballs) is discouraged because it accumulates in the wax, which can kill bees or contaminate honey stores. Control of wax moths by other means includes the freezing of the comb for at least twenty-four hours.
Bacterial diseases
Appearance of brood comb | Age of dead brood | Color of dead brood | Consistency of dead brood | Odor of dead brood | Scale characteristics | Infectious agent |
---|---|---|---|---|---|---|
Sealed brood. Discolored, sunken, or punctured cappings. | Usually older sealed larvae or young pupae. Lying lengthwise in cells. | Dull white, becoming light brown, coffee brown to dark brown, or almost black. | Soft, becoming sticky to ropy. | Slightly to pronounced putrid odor. | Lies uniformly flat on lower side of cell. Adheres tightly to cell wall. Fine, threadlike tongue of dead maybe present. Head lies flat. Black in color. | American Foulbrood |
Unsealed brood. Some sealed brood in advanced cases with discolored, sunken or punctured cappings. | Usually young unsealed larvae; occasionally older sealed larvae. Typically in coiled stage. | Dull white, becoming yellowish white to brown, dark brown, or almost black. | Watery; rarely sticky or ropy. Granular. | Slightly to penetrating sour. | Usually twisted in cell. Does not adhere to cell wall. Rubbery. Black in color. | European foulbrood |
American foulbrood
American foulbrood (AFB), caused by the spore- forming Paenibacillus larvae ssp. larvaePaenibacillus
'Paenibacillus' is a genus of Gram-positive, facultative anaerobic, endospore-forming bacteria, originally included within the genus Bacillus and then reclassified as a separate genus in 1993. Bacteria belonging to this genus have been detected in a variety of environments such as: soil, water,...
(formerly classified as Bacillus larvae), is the most widespread and destructive of the bee brood diseases. Paenibacillus larvae is a rod-shaped bacterium, which is visible only under a high power microscope. Larvae up to 3 days old become infected by ingesting spores that are present in their food. Young larvae less than 24 hours old are most susceptible to infection. Spores germinate in the gut of the larva and the vegetative form of the bacteria begins to grow, taking its nourishment from the larva. Spores will not germinate in larvae over 3 days old. Infected larvae normally die after their cell is sealed. The vegetative form of the bacterium will die but not before it produces many millions of spores. Each dead larva may contain as many as 100 million spores. This disease only affects the bee larvae but is highly infectious and deadly to bee brood. Infected larvae darken and die.
European foulbrood
Melissococcus plutonius is a bacterium that infests the mid-gut of an infected bee larva. European foulbrood is less deadly to a colony than American foulbrood. Melissococcus plutonius does not form spores, though it can overwinter on comb. Symptoms include dead and dying larvae which can appear curled upwards, brown or yellow, melted or deflated with tracheal tubes more apparent, and/or dried out and rubbery.European foulbrood is often considered a "stress" disease—a disease that is dangerous only if the colony is already under stress for other reasons. An otherwise healthy colony can usually survive European foulbrood. An outbreak of the disease may be controlled chemically with oxytetracycline hydrochloride, but honey from treated colonies could have chemical residues from the treatment. The 'Shook Swarm' technique of bee husbandry can also be used to effectively control the disease, the advantage being that chemicals are not used. Prophylactic treatments are not recommended as they lead to resistant bacteria.
Chalkbrood
Ascosphaera apis is a fungal disease that infests the gut of the larva. The fungus will compete with the larva for food, ultimately causing it to starve. The fungus will then go on to consume the rest of the larva's body, causing it to appear white and 'chalky'.Chalkbrood is most commonly visible during wet springs. Hives with Chalkbrood can generally be recovered by increasing the ventilation through the hive.
Stonebrood
Stonebrood is a fungal disease caused by Aspergillus fumigatusAspergillus fumigatus
Aspergillus fumigatus is a fungus of the genus Aspergillus, and is one of the most common Aspergillus species to cause disease in individuals with an immunodeficiency....
, Aspergillus flavus
Aspergillus flavus
Aspergillus flavus is a fungus. It is a common mold in the environment, and can cause storage problems in stored grains. It can also be a human pathogen, associated with aspergillosis of the lungs and sometimes causing corneal, otomycotic, and nasoorbital infections. Many strains produce...
and Aspergillus niger
Aspergillus niger
Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus. It causes a disease called black mold on certain fruits and vegetables such as grapes, onions, and peanuts, and is a common contaminant of food...
. It causes mummification of the brood of a honey bee colony. The fungi are common soil inhabitants and are also pathogenic to other insects, birds and mammals. The disease is difficult to identify in the early stages of infection. The spores of the different species have different colours and can also cause respiratory damage to humans and other animals. When a bee larva takes in spores they may hatch in the gut, growing rapidly to form a collarlike ring near the head. After death the larvae turn black and become difficult to crush, hence the name stonebrood. Eventually the fungus erupts from the integument of the larva and forms a false skin. In this stage the larvae are covered with powdery fungal spores. Worker bees clean out the infected brood and the hive may recover depending on factors such as the strength of the colony, the level of infection, and hygienic habits of the strain of bees (there is variation in the trait among different subspecies/races).
Chronic Paralysis Virus [CPV]
- Syndrome 1 Abnormal trembling of the wings and body. The bees cannot fly and often crawl on the ground and up plant stems. In some cases the crawling bees can be in large numbers (1000+). The bees huddle together on the top of the cluster or on the top bars of the hive. They may have bloated abdomens due to distension of the honey sac. The wings are partially spread or dislocated.
- Syndrome 2 Affected bees are able to fly but are almost hairless. They appear dark or black and look smaller. They have a relatively broad abdomen. They are often nibbled by older bees in the colony and this may be the cause of the hairlessness. They are hindered at the entrance to the hive by the guard bees. A few days after infection trembling begins. They then become flightless and soon die.
Acute bee paralysis virus (ABPV) or (APV)
ABPV (TaxID 92444) is considered to be a common infective agent of bees. It belongs to the family DicistroviridaeDicistroviridae
The Dicistroviridae are a family of Group IV insect-infecting viruses. Some of the insects commonly infected by dicistroviruses include aphids, leafhoppers, flies, bees, ants, silkworms.-Taxonomy:...
,http://www.picornavirales.org/dicistroviridae/dicistroviridae.htm as does the Israel acute paralysis virus, Kashmir bee virus, and the Black queen cell virus. It is frequently detected in apparently healthy colonies. Apparently, this virus plays a role in cases of sudden collapse of honey bee colonies infested with the parasitic mite Varroa destructor.
Israel acute paralysis virus (IAPV)
A related virus http://www.picornavirales.org/dicistroviridae/dicistroviridae.htm described in 2004 is known as the "Israel acute paralysis virus" (TaxID 294365); The virus is named after the place where it was first identified—its place of origin is unknown. IAPV http://www.beeologics.com/iapv.asp has been suggested in September 2007 as a marker associated with Colony Collapse DisorderColony Collapse Disorder
Colony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...
.
Kashmir bee virus (KBV)
This is another Dicistroviridae, related to the preceding viruses.http://www.picornavirales.org/dicistroviridae/dicistroviridae.htm Recently discovered, KBV (TaxID 68876) is currently only positively identifiable by a laboratory test. Little is known about it yet.Black Queen Cell Virus (BQCV)
This is another Dicistroviridae, related to the preceding viruses.http://www.picornavirales.org/dicistroviridae/dicistroviridae.htm As its name implies, BQCV (TaxID 92395) causes the queen larva to turn black and die. It is thought to be associated with NosemaNosema
For the genus in Lamiaceae, the mint family, see Nosema .Nosema is a genus of microsporidian parasites, including*Nosema algerae parasitising mosquitoes*Nosema antheraeae parasitising the Chinese oak silkworm Antheraea pernyi...
.
Cloudy Wing Virus (CWV)
Cloudy wing virus (CWV) is a little studied small icosahedral virus commonly found in honey bees (Apis mellifera), especially in collapsing colonies infested by Varroa destructor, providing circumstantial evidence that the mite may act as a vector.Sacbrood virus (SBV)
Morator aetatulas is the virus that causes sacbrood disease. Affected larvae change from pearly white to gray and finally black. Death occurs when the larvae are upright, just before pupation. Consequently, affected larvae are usually found in capped cells. Head development of diseased larvae is typically retarded. The head region is usually darker than the rest of the body and may lean toward the center of the cell. When affected larvae are carefully removed from their cells, they appear to be a sac filled with water. Typically the scales are brittle but easy to remove. Sacbrood-diseased larvae have no characteristic odor.Deformed Wing Virus (DWV)
As indicated by the name, this virus produces deformed wings. Typically associated with Varroa destructorVarroa destructor
Varroa destructor is an external parasitic mite that attacks honey bees Apis cerana and Apis mellifera. The disease caused by the mites is called varroatosis....
, it has been suggested as a contributing factor to Colony Collapse Disorder
Colony Collapse Disorder
Colony collapse disorder is a phenomenon in which worker bees from a beehive or European honey bee colony abruptly disappear. While such disappearances have occurred throughout the history of apiculture, the term colony collapse disorder was first applied to a drastic rise in the number of...
.
This deformity can clearly be seen on the honeybee's wings. As a result, bees are unable to leave the hive and forage for pollen and nectar, possibly leading to the colony starving.
Kakugo virus (KV)
This is an iflavirusIflavirus
The Iflaviridae is a genus of Group IV insect-infecting viruses. Some of the insects commonly infected by dicistroviruses include aphids, leafhoppers, flies, bees, ants, silkworms.-Taxonomy:...
infecting bees. Research suggests that varroa mites mediate KV prevalence.
Invertebrate iridescent virus type 6 (IIV-6)
Applying proteomicsProteomics
Proteomics is the large-scale study of proteins, particularly their structures and functions. Proteins are vital parts of living organisms, as they are the main components of the physiological metabolic pathways of cells. The term "proteomics" was first coined in 1997 to make an analogy with...
-based pathogen screening tools in 2010, researchers announced they had identified a co-infection of an iridovirus
Iridoviridae
Iridoviridae are a family of viruses with double stranded DNA genomes. The name is derived from Iris the Greek goddess of the rainbow. This name was chosen because of the "rainbow like" iridescence observed in heavily infected insects and pelleted samples of invertebrate iridoviruses.-Taxonomy:The...
; specifically invertebrate iridescent virus type 6 (IIV-6) and Nosema ceranae
Nosema ceranae
Nosema ceranae is a microsporidian, a small, unicellular parasite that mainly affects Apis cerana, the Asiatic honey bee. It may cause nosemosis, also called nosema...
in all CCD colonies sampled. On the basis of this research, the New York Times reported the colony collapse mystery solved, quoting researcher Dr. Bromenshenk, a co-author of the study, "[The virus and fungus] are both present in all these collapsed colonies.”
Dysentery
DysenteryDysentery
Dysentery is an inflammatory disorder of the intestine, especially of the colon, that results in severe diarrhea containing mucus and/or blood in the faeces with fever and abdominal pain. If left untreated, dysentery can be fatal.There are differences between dysentery and normal bloody diarrhoea...
is a condition resulting from a combination of long periods of inability to make cleansing flights (generally due to cold weather) and food stores which contain a high proportion of indigestible matter. As a bee's gut becomes engorged with feces that cannot be voided in flight as preferred by the bees, the bee voids within the hive. When enough bees do this the hive population rapidly collapses and death of the colony results. Dark honeys and honeydew
Honeydew (secretion)
Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the gut's terminal opening. Honeydew is particularly common as a secretion in the Hemipteran...
s have greater quantities of indigestible matter.
Occasional warm days in winter are critical for honey bee survival; dysentery problems increase in likelihood if there are periods of more than two or three weeks with temperatures below 50 degrees Fahrenheit (10 degrees Celsius). When cleansing flights are few, bees will often be forced out at times when the temperature is barely adequate for their wing muscles to function, and large quantities of bees may be seen dead in the snow around the hives.
Colonies that are found dead in spring from dysentery will have feces smeared over the frames and other hive parts.
In very cold areas of North America and Europe, where honey bees are kept in ventilated buildings during the coldest part of winter, no cleansing flights are possible; under such circumstances, it is common for beekeepers to remove all honey from the hives and replace it with sugar water or high fructose corn syrup, which have nearly no indigestible matter.
Chilled brood
Chilled brood is not actually a disease but can be a result of mistreatment of the bees by the beekeeper. It also can be caused by a pesticide hit that primarily kills off the adult population, or by a sudden drop in temperature during rapid spring buildup.The brood must be kept warm at all times; nurse bees will cluster over the brood to keep it at the right temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
.
When a beekeeper opens the hive (to inspect, remove honey, check the queen, or just to look) and prevents the nurse bees from clustering on the frame for too long, the brood can become chilled, deforming or even killing some of the bees.
To minimize the risk of chilled brood, open the hive on warm days and at the hottest part of the day (this is also the time when the most field bees will be out foraging and the number of bees in the hive will be at its lowest). Learn to inspect your hive as quickly as possible and put frames with brood back where the bees can cluster on it immediately.
Pesticide losses
Honey bees are susceptible to many of the chemicals used for agricultural spraying of other insects and pests. Many pesticides are known to be toxic to beesBees and toxic chemicals
Bees can suffer serious effects from toxic chemicals in their environments. These include various synthetic chemicals, such as insecticides and fertilizers, as well as a variety of naturally occurring chemicals from plants, such as ethanol resulting from the fermentation of organic material...
.
Because the bees forage up to several miles from the hive, they may fly into areas actively being sprayed by farmers or they may collect pollen from 'contaminated' flowers.
Carbamate
Carbamate
Carbamates are organic compounds derived from carbamic acid . A carbamate group, carbamate ester, and carbamic acids are functional groups that are inter-related structurally and often are interconverted chemically. Carbamate esters are also called urethanes.-Synthesis:Carbamic acids are derived...
pesticides, such as Sevin(R)-Carbaryl (C12H11NO2)can be especially pernicious since toxicity can take as long as two days to become effective; allowing infected pollen to be returned and distributed throughout the colony. Organophosphates and other insecticides are also known to kill honey bee clusters in treated areas
Pesticide toxicity to bees
Pesticides vary in their effects on bees. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other media...
.
Pesticide losses may be relatively easy to identify (large and sudden numbers of dead bees in front of the hive) or quite difficult, especially if the loss results from a gradual accumulation of pesticide brought in by the foraging bees. Quick acting pesticides may deprive the hive of its foragers, dropping them in the field before they can return home.
Insecticides that are toxic to bees have label directions that protect the bees from poisoning as they forage. To comply with the label, applicators must know where and when bees forage in the application area, and the length of residual activity of the pesticide.
Some pesticide authorities recommend, and some jurisdictions require, that notice of spraying be sent to all known beekeepers in the area so that they can seal the entrances to their hives and keep the bees inside until the pesticide has had a chance to disperse. This, however, does not solve all problems associated with spraying and the label instructions should be followed regardless of doing this. Sealing honey bees from flight on hot days can kill bees. Beekeeper notification does not offer any protection to bees, if the beekeeper cannot access them, or to wild native or feral honey bees. Thus beekeeper notification as the sole protection procedure does not really protect all the pollinators of the area, and is, in effect, a circumventing of the label requirements. Pesticide losses are a major factor in pollinator decline
Pollinator decline
The term pollinator decline refers to the reduction in abundance of pollinators in many ecosystems worldwide during the end of the twentieth century....
.
Colony Collapse Disorder
Colony Collapse Disorder (or CCD) is a little-understood phenomenon in which worker bees from a beehiveBeehive (beekeeping)
A beehive is an enclosed structure in which some honey bee species of the subgenus Apis live and raise their young. Natural beehives are naturally occurring structures occupied by honeybee colonies, while domesticated honeybees live in man-made beehives, often in an apiary. These man-made...
or Western honey bee colony abruptly disappear. CCD was originally found in Western honey bee colonies in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
in late 2006.
European beekeepers observed a similar phenomenon in Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
, and Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, and initial reports have also come in from Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
and Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, albeit to a lesser degree. Possible cases of CCD have also been reported in Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
since April 2007.
Initial hypotheses were wildly different including environmental change-related stresses, malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
, pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s (i.e., disease including Israel acute paralysis virus), mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
s, pesticide
Pesticide toxicity to bees
Pesticides vary in their effects on bees. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other media...
s such as neonicotinoids
Neonicotinoids
Neonicotinoids are a class of insecticides which act on the central nervous system of insects with lower toxicity to mammals. Neonicotinoids are among the most widely used insecticides worldwide, but recently the uses of some members of this class have been restricted in some countries due to a...
or imidacloprid
Imidacloprid
Imidacloprid is a nicotine-based, systemic insecticide, which acts as a neurotoxin and belongs to a class of chemicals called the neonicotinoids. Although it is now off patent, the primary manufacturer of this chemical is Bayer CropScience,...
, radiation from cellular phones or other man-made devices,
and genetically modified (GM) crops
Genetically modified food
Genetically modified foods are foods derived from genetically modified organisms . Genetically modified organisms have had specific changes introduced into their DNA by genetic engineering techniques...
with pest control characteristics such as transgenic maize
Transgenic maize
Genetically modified maize has been deliberately genetically modified to have agronomically desirable traits. Traits that have been engineered into corn include resistance to herbicides and resistance to insect pests, the latter being achieved by incorporation of a gene that codes for the...
. In 2010, US researchers announced they had identified a co-infection of invertebrate iridescent virus type 6 (IIV-6) and Nosema ceranae in all CCD colonies sampled.
Further reading
- Canadian Honey Council Essential Oils for Varroa, Tracheal, AFB Control
- Sammataro, Diana; et al. The Beekeeper's Handbook
- Morse, Roger (editor) The ABC and XYZ of Beekeeping
External links
- Beekeeping page at the University of Georgia, with a large section on Honey Bee Disorders]
- Apiculture Factsheets at the British Columbia Ministry of Agriculture and Lands
- BeeBase at the Defra Food and Environment Research Agency in the UK
- Kohala.net Diseases and Afflictions of Honey Bees