Cletus Calendar
March 2019

Where ever you live in the world you should apply the information on working your bees that is given below when the weather conditions in your area are right. So take notes and be ready.

*****Check out the new easy to use book link above*****

Cletus Notes

Honey Bee


Varroa mite

(Varroa destructor)

Varroa mites are a serious malady of honey bees. They

occur nearly everywhere honey bees are found, and all

beekeepers should assume their bees have a varroa mite

infestation. These external parasites feed on the hemolymph

(blood) of adult bees and capped brood.

Life history

• A dult female varroa mite

Only mature female mites survive on adult honey bees

and can be found on both workers and drones and

rarely on queens. Varroa mites are reddish brown in

color, about the size of a pin head, and can be seen

with the naked eye. Their flat shape allows them to

squeeze between overlapping segments of a bee’s abdomen

to feed and escape removal by grooming bees.

Their flat shape also permits them to move easily in

the cells of developing bee brood. Male mites are

smaller and light tan in color. Adult males do not feed

and are not found outside of brood cells.

 Varroa mite life cycle

 When female mites are ready to lay eggs, they move

into brood cells containing larvae just before the cells

are capped. After the cells are capped and the larvae

have finished spinning cocoons, the mites start feeding

on the brood. The foundress mites begin laying

eggs approximately three days after the cell has been

capped. A fertilized female mite lays one unfertilized

(male) egg and four to six fertilized (female) eggs. The

adult female and its immature offspring feed at a hole

pierced in the developing pupae by the foundress

mite. Only mature female mites will survive when their

host bee emerges as an adult.

 Different life stages of varroa mite feeding

on a drone bee (just before emerging)

 The mite life cycle consists of four developmental

stages: the egg, two eight-legged nymphal stages

(protonymph and deutonymph), and the adult. The

period from egg to adult takes about six to seven

days for female mites. Female mites produced in the

summer live two to three months, and those produced

in the fall live five to eight months. Without bees and

brood, the mites can survive no more than a few days.

 merging worker bee with varroa mites

 Mating of male and female mites occurs in the brood

cells before the new adult females emerge. The adult

male dies after copulation since its mouthparts (chelicerae)

are modified for sperm transfer. The foundress

(old) female and the newly fertilized female offspring

remain in the brood cell until the young bee emerges.

The adult bee then serves as an intermediate host and

a means of transport for these female mites.

 Varroa mites on drone pupa

 As only mature female mites can survive when the

host bee emerges, few of the eggs each foundress

mite lays will survive to adulthood. On average a mite

invading a worker cell will have 1.2 offspring. If the

same female invades a drone cell, she will have on

average 2.2 offspring. For this reason, more mites per

cell are produced in drone brood.

 Field diagnosis

 Monitoring and recognizing a varroa infestation before

it reaches a critical level is important. All beekeepers

should have a varroa management plan in place before

an infestation reaches a harmful level. Beekeepers

should integrate a combination of soft chemical and

nonchemical techniques to manage mite populations.

For detailed information on treatment strategies and

currently registered chemicals approved for the control

of honey bee varroa mites, see the MAAREC Web site,

 Examining Drone Brood

 One technique to quickly assess the presence of varroa

mites is by examining brood—uncap cells and remove

and examine pupae, especially white drone pupae.

Individual pupae can be removed using forceps, or many

drone pupae can be removed at once using an uncapping

fork. In addition, drone brood is often housed

between boxes and is broken open when boxes are separated

during routine inspections. This is a good place

and time to examine brood for mites. A small 10x hand

lens will be helpful.

 Deformed wings

Varroa mites can transmit and/or activate some bee

viruses. Few of these viruses produce visible symptoms.

An exception is deformed wing virus (DWV),

which when present in high levels causes developing

bees to have malformed wings. When large numbers

of bees in a colony have DWV, the colony likely has

high varroa populations and immediate intervention

to control the varroa population is required.

 Parasitic mite syndrome

 Parasitic mite syndrome (PMS) is a condition associated

with high varroa infestation. The exact cause of

PMS is unknown, although viruses are suspect. This

condition is characterized by a spotty brood pattern

and dead brood found in cells that are discolored,

turning a yellow brown to dark brown color. Signs

of this condition can resemble American foulbrood,

but dead larvae do not string out, as with American

foulbrood, when the ropiness test is preformed (see

page 34). Dead larvae can also resemble European

foulbrood and/or sacbrood infections. Both capped

(or once capped) and uncapped brood are affected.

Other names associated with this condition include

snotty brood and cruddy brood.

 Crawling bees abandoning the hive

 Another common symptom of a heavy mite infestation

is large numbers of bees that are often hairless,

greasy looking with extended abdomens, and unable

to fly and are thus crawling out of infested hives.

These crawling bees may or may not show signs of

viral infection, such as deformed wings.

 Spotty or irregular brood pattern

 Brood combs in an infested colony have a scattered or

irregular pattern of capped and uncapped cells. This

may be especially evident in highly hygienic colonies.

 • Sudden summer/fall collapse

 The collapse of colonies, particularly strong colonies,

in the late summer and early fall is a possible symptom

of a significant infestation of varroa mites and the

diseases associated with these mites.

 Honey bee tracheal mite

 (Acarapis woodi)

Another mite that can negatively affect honey bees is

the honey bee tracheal mite. This internal parasitic mite

lives within the tracheae, or breathing tubes, of adult

honey bees. The mites pierce the breathing tube walls

with their mouthparts and feed on the hemolymph

(blood) of the bees. In recent years, tracheal mites have

been a minimal problem for beekeepers and it appears

that U.S. honey bees have developed resistance to these


 Tracheal mite life cycle

 The honey bee tracheal mite is difficult to identify

and study because of its small size (no bigger than

a dust speck). The entire life cycle of this mite is

spent within the respiratory (tracheal) system of the

honey bee, except for brief migratory periods. Female

tracheal mites migrate to young adult bees (less than

four days old). Once in the bees’ tracheae, the mites

feed and reproduce. Each female mite lays five to

seven eggs, which require three to four days to hatch.

Male and female mites develop from egg to adult in

approximately eleven to fifteen days. Eggs hatch into

six-legged larvae, then molt to a nonfeeding or pharate

nymph stage, and finally molt to the adult stage.

All stages of the mite may be found in the tracheae of

older infected bees. Only adult females emerge from

the tracheae through spiracles (openings to the outside).

Close contact among bees permits the mites to

transfer to uninfested young bees. Bees less than four

days old are the most susceptible.

 Winter cluster with reduced population

 A tracheal mite infestation shortens the lives of adult

bees and affects flight efficiency and perhaps the

ability of bees to thermoregulate. As mite populations

increase, colony populations dwindle, which ultimately

leads to colony death. Infested colonies often die in

late winter or early spring. Severely infested colonies

also can die during the spring, summer, or fall.

 Mass of bees exiting hive

 When a colony is near death, large numbers of bees

can be seen crawling out of the hive, unable to fly.

These bees may display abnormally positioned wings

that look disjointed (“K” wings) and may be trembling,

symptoms that can result from diseases associated

with the tracheal mites.

 Infested tracheae

 A severe infestation can be identified in the field by

detaching the head from the thorax to expose the

large tracheal trunks in the thorax. This is most easily

done with drone bees. Normally, these tracheal tubes

are opaque. When infested with a high level of mites,

the tubes will be blotchy with patches of brown or

black. When infestation is particularly severe, the

tubes can be solid black. A light infestation is difficult

to detect and can be identified only with the aid of a


 Healthy and infested tracheae

(under microscope)

 Positive identification of tracheal mites is best done

by dissection and microscopic examination of worker

bee thoracic tracheae. The tracheae of uninfested

bees are clear and colorless or pale amber in color

(healthy). In a slight infestation, one or both tracheal

tubes contain a few adult mites and eggs, which

may be detected near the spiracular openings. At

this stage, the tracheae may appear clear, cloudy, or

slightly discolored (infested). The tracheae of severely

infested bees have brown blotches with brown scabs

or crustlike lesions, or may appear completely black,

and are obstructed by numerous mites in different

stages of development. Feeding by the mites damages

stages of development. Feeding by the mites damages

the walls of the tracheae. Flight muscles in the bee’s

thorax also may become atrophied as a result of a

severe infestation.

 American foulbrood

 American foulbrood (AFB) is an infectious brood disease

caused by the spore-forming bacterium Paenibacillus

larvae. It is the most widespread and destructive of the

brood diseases. Adult bees, while not affected by AFB,

do carry the disease. American foulbrood spores are

highly resistant to desiccation, heat, and chemical disinfectants.

These spores can remain viable for more than

seventy years in combs and honey.

 Punctured, sunken cappings

 Paenibacillus larvae occur in two forms: vegetative (rodshaped

bacterial cells) and spores. Only the spore

stage is infectious to honey bees. Larvae less than

2.5 days old become infected by swallowing spores

present in their food. Older larvae are not susceptible.

 The spores germinate into the vegetative stage soon

after they enter the larval gut and continue to multiply

until larval death. Death typically occurs after the cell

has been capped, during the last two days of the larval

stage or the first two days of the pupal stage. New

spores form after the larva or pupa dies. Symptoms of

this disease are only present in larvae that are or were

once capped. Adult bees typically puncture but often

delay removing diseased larvae.

 Dead, melted larvae

 Dead larvae change gradually from a healthy pearly

white to a light brown and then to a darker brown.

This color change is uniform over the entire body. The

infected larvae look melted and lie flat on the bottom

side of the cell. The disease has a distinctive odor,

but the odor alone is not a reliable symptom for

identification and so should be backed up with lab


 Scale of American foulbrood

 Within a month or so, these dead larvae dry out and

form brittle scales that are almost black. Each scale

contains as many as 100 million AFB spores. The

scales lie flat along the lower walls of the cells with

the rear portion curving partway up the bottom of the

cell. It is very difficult for bees or beekeeper to remove

the scales from the cells.

 Pupal “tongue”

 If death occurs during the pupal stage, pupae undergo

the same changes in color and consistency as larvae.

In addition, the pupal “tongue,” or proboscis, sometimes

sticks to the top wall of the cell. The presence

of this pupal tongue, though not always present, is a

characteristic symptom of American foulbrood.

 Irregular brood pattern

Brood combs in an infected colony have a scattered

and irregular pattern of capped and uncapped cells.

Infected cells are discolored, sunken, and often have

punctured cappings. This appearance contrasts with

the yellowish brown, convex, and entirely sealed cells

of a healthy brood comb.

 Field testing

 During the early stages of decay until about three

weeks after death, the dead larvae have a gluelike

consistency. To test for the disease, choose a larva

that is discolored and exhibits a melted appearance.

Insert a match, twig, or toothpick into the cell, stir the

remains of the dead larva, and then slowly withdraw

the test stick. If a portion of the decaying larva clings

to the twig and can be drawn out about an inch or

more while adhering to the dead mass, its death was

probably due to AFB. This “ropiness” of freshly dead

larvae is a characteristic symptom of AFB.

 Laboratory diagnosis

 To obtain positive confirmation of AFB, contact your

state apiary inspection service (see the AIA Web site,, for a complete list of

state apiary inspection programs) or send a sample of

diseased larvae to the Beltsville Bee Lab (see resources

for address). Samples for lab diagnosis can be collected

in one of two ways: several diseased larvae are

collected using a toothpick or thin twig and placed into

plastic wrap or wax paper, or a 1-inch-by-1-inch piece of

comb can be cut from the diseased frame and wrapped

in wax paper. A diagnostic test kit by Vita is also available

from some beekeeping supply companies

 HOLTS milk test—preparing powdered milk

Another field test to confirm the presence of AFB can

be conducted using powdered milk. Combine one

teaspoon of the powdered milk with 100 milliliters

(slightly less than half cup) of water and mix thoroughly.

Pour the milk into two small, clear, glass vials

or other similar containers.

Collecting an AFB sample

Collect a sample from the suspect AFB colony by

opening a diseased cell and stirring the contents

with a toothpick. Collect as much of the larval remains

as possible on the toothpick and place in a clean

container or wrap in foil.

 Positive AFB sample

 Insert the previously collected AFB sample into one

of the prepared vials. Do nothing with the second

sample. Place both vials in a warm location for one

hour. After one hour examine the samples. If the

sample is positive, the vial with the AFB sample will

become clear. Use the second sample for comparison.

 Hive inspection

 The secret to successfully controlling American foulbrood

in the apiary is to find the disease in its early

stages. The beekeeper should therefore make careful

inspections of the brood area of the colonies minimally

once in spring and again in the fall and always

be alert for possible signs of the disease.

 European foulbrood

 European foulbrood (EFB) is a bacterial brood disease

caused by the bacterium Melissococcus pluton. This disease

is considered a stress disease and is most prevalent in

spring and early summer. Melissococcus pluton does not

form spores but often overwinters on combs. It gains

entry into the larva in contaminated brood food and

multiplies rapidly within the gut of the larva.

European foulbrood frequently disappears with a

nectar flow. Occasionally, the disease remains active

throughout the entire foraging season. All castes of bees

are susceptible, although various commercial strains

differ in susceptibility.

 Life history

  Young diseased larvae in open cells

 European foulbrood disease and its symptoms are

highly variable, probably because several other types

of bacteria are often present in dead and dying larvae.

EFB generally kills larvae that are two to four days

old while they are still C shaped in the bottom of the

cells. Unlike American foulbrood, most of the larvae

die before their cells are capped. A spotty pattern of

capped and uncapped cells develops only when EFB

becomes serious. Occasionally, pupae die from the


 Blotchy and twisted EFB brood

 The most significant symptom of EFB is the nonuniform

color change of the larvae. They change from a

normal pearly white to yellowish, then to brown, and

finally to grayish black; they can also be blotchy or

mottled. Infected larvae lose their plump appearance

and look undernourished. Their breathing tubes, or

tracheae, are visible as distinct white lines. Larval

remains often appear twisted or melted to the bottom

side of the cell. Unlike larvae killed by AFB, recently

killed larvae rarely pull out in a ropy string when

tested with a toothpick. The dead larvae form a thin,

brown or blackish brown scale that can be easily removed.

EFB usually does not kill colonies, but a heavy

infection can seriously affect population growth.


Chalkbrood, a fungal brood disease of honey bees, is

caused by the spore-forming fungus Ascophaera apis.

 Life history

 Bees ingest spores of the fungus with the larval food.

The spores germinate in the hind gut of the bee larva,

but mycelial (vegetative) growth is arrested until the

larva is sealed in its cell. When the larva is about six or

seven days old and sealed in its cell, the mycelia break

through the gut wall and invade the larval tissues until

the entire larva is overcome. This process generally takes

from two to three days.

 Chalkbrood mummies

Dead larvae are chalky white and usually covered

with fungus filaments (mycelia) that have a fluffy,

cottonlike appearance. These mummified larvae may

be mottled with brown or black spots, especially on

the undersides, because of the presence of maturing

fungal fruiting bodies. Larvae that have been dead for

a long time may become completely black as these

fruiting bodies fully mature. The chalkbrood mummies

are hard and resemble pieces of chalk when white.

 Chalkbrood in cells

 Diseased larvae can be found throughout the broodrearing

season but are most prevalent in late spring

when the brood nest is expanding rapidly. Affected

larvae are found on the outer fringes of the brood nest

where insufficient nurse bees are available to maintain

an elevated brood nest temperature. Drone brood

is particularly susceptible to chalkbrood. Symptoms

appear only after capping; however, workers often

puncture or remove cappings.

 Chalkbrood at hive entrance

 Nurse bees remove infected larvae, which are

stretched out in their cells. Dead larvae (mummies)

are often found in front of the hive, on the landing

board, or in a pollen trap. In strong colonies, most

of these mummies will be discarded by worker bees

outside the hive, thus reducing the possibility of reinfection

from those that have died from chalkbrood.

Improving ventilation can help prevent chalkbrood.


 Sacbrood, a disease caused by a virus, usually does not

result in severe losses. It is most common during the

first half of the brood-rearing season and often goes

unnoticed since it usually affects only a small percentage

of the brood. Adult bees typically detect and remove

infected larvae quickly. Often, if sacbrood is widespread

enough for the beekeeper to observe the symptoms, the

disease may be too severe for the adult worker population

to handle.

 Sealed cells with punctures and affected


 Both worker and drone larvae can be infected by

sacbrood. Death usually occurs after the cell is sealed

and the larva has spun its cocoon. Pupae may be

killed occasionally, but adult bees are not susceptible

to the disease. Dead brood is often scattered

among healthy brood. The cappings over dead brood

are punctured first, and the affected brood is later

removed by the bees. The larvae gradually change

from pearly white to dull yellow or gray and finally

to black. The head of the larva, the first part of the

body to change color, becomes black. Larvae die in a

stretched-out position with their heads raised.

 Sacbrood-infected larva

 Larvae with sacbrood are easily removed intact from

the cells, unlike those killed by foulbrood. When

removed, the contents of the larvae are watery, and

the tough outer skin appears as a sack of fluid filled

with millions of sacbrood virus particles. The dried

sacbrood scale lies flat, with the head end raised

and darkened and the tail flat on the bottom side of

the cell. The scales are rough and brittle and do not

adhere tightly to the cell wall. Sacbrood usually

disappears in the late spring when the honey flow

has started.

 Cultural control

 If symptoms persist, re-queening—especially with

hygienic stock—is recommended.


 Nosema is caused by the spore-forming microsporidum

Nosema apis or Nosema ceranae, which invades the digestive

tracts of honey bee workers, queens, and drones. Adult

bees ingest Nosema spores with food or water. The spores

germinate and multiply within the lining of the bee’s

midgut. Millions of spores are shed into the digestive

tract and eliminated in the feces.

Fecal staining on outside of hive

 Nosema disease may be present at any time during

the year. Nosema ceranae appears to be more common

during summer and is sometimes referred to as

“dry nosema” as heavy loads of this pathogen do not

cause the characteristic fecal staining associated with

Nosema apis, which appears in fall and winter. Damage

to the digestive tract may produce symptoms of

dysentery (diarrhea). Especially in winter, infected

workers, unlike healthy workers, may defecate in or

on the outside of the hive rather than out in the field.

Diseased colonies usually have increased winter

losses and decreased honey production. When queens

become infected, egg production and life span are reduced,

leading to supersedure. The loss of the queen in colonies newly started from package bees is a

serious effect of the disease. Infection in worker bees

inhibits digestion of food in the stomach and production

of royal jelly. As a result, the productive life of the

worker is shortened and its ability to produce brood

food decreases, thus retarding brood production and

colony development.

 Comparison of healthy and diseased

honey bee gut

 The only way to positively identify nosema disease is

through the dissection of adult bees. The hind gut and

digestive tract of diseased bees are chalky or milky

white. Healthy bees, on the other hand, have amber or

translucent digestive tracts. In addition, the individual

circular constrictions of a healthy bee’s gut are visible,

whereas the gut of an infected bee may be swollen

and the constrictions may not be clearly visible.

More commonly, bee abdomens are masticated

in a known quantity of water and an aliquot of the

suspension is examined under 100x magnification for

presence of Nosema spores.

 cultural control

 Keeping colonies strong and producing abundant

healthy brood in fall is important.

 Honey bee viruses

 Viruses are small packages of genetic material that rely

on another organism to reproduce. More than sixteen

viruses have been found in European honey bees, eleven

of which have been found in North America. Most viruses

do not cause overt symptoms in the colonies they

infect. Many viruses are not thought to have a significant

impact on colonies unless the colony is also infested

with parasites (e.g., varroa and honey bee tracheal

mites) or other pathogens (e.g., Nosema) that aggravate

and or transmit the virus. Most viruses are associated

with adult bees, except sacbrood (discussed on page 42)

and black queen cell virus (BQCV).

 Black queen cell virus

 This virus is closely associated with nosema infection,

although infected colonies typically do not show overt

signs of nosema infection. It is unique in that the virus

only replicates in the larvae of queens. Diseased larvae

or prepupae die after the queen cell has been capped.

After death the larvae have a pale yellow appearance and

are surrounded by a tough saclike skin that resembles

sacbrood infection. This disease may be problematic in

queen-rearing operations, where cells containing diseased

individuals develop dark brown to black cell walls.

Deformed wing virus

 Varroa mites can transmit and/or activate some bee

viruses. While few of these viruses produce visible symptoms,

an exception is deformed wing virus (DWV), which

when present in high levels causes developing bees to

have malformed wings. When large numbers of bees in

a colony have DWV, the colony likely has a high varroa

population, requiring immediate intervention to control

the infestation.

Chronic paralysis virus

 Chronic paralysis virus produces two sets of symptoms.

Both sets of symptoms can occur in the same colony, but

one usually predominates, probably because the symptoms

an individual bee is likely to manifest are heritable.

 Trembling syndrome and

hive abandonment

 Some bees infected with chronic paralysis virus are unable

to fly and can be seen crawling, often climbing up

stems of grass. In severe cases, thousands of bees from

a colony may demonstrate this behavior. The individual

bee’s body and wings often tremble abnormally, and

the abdomen may appear distended. Infected bees die

within a couple of days of symptoms appearing, and

colonies can suddenly collapse if large numbers of bees

are infected.

 Hairless black syndrome

 Some bees infected with chronic paralysis virus appear

smaller than other bees, are dark to black in color, and

have a shiny, greasy appearance. Nest mates are sometimes

seen “nibbling” on infected individuals, making it

easy to mistake them for older robber bees. Symptomatic

bees are unable to fly, will begin to tremble, and die

within a couple of days.

Greasy, hairless bees

 Some bees infected with chronic paralysis virus tremble

uncontrollably and are unable to fly. In addition, they

lose the hair from their bodies and have a dark, shiny,

or greasy appearance. They are often mistaken for robber

bees, but paralytic bees are submissive to attack,

whereas robbing bees are not.

 Bees with K wings

 When chronic paralysis virus is serious, large numbers

of afflicted bees can be found at the colony entrance

crawling up the sides of the hive and/or blades of grass

around the hive and then tumbling to the ground.

 Healthy bees often tug at infected bees in an effort to

drive them away from the hive. Infected bees may also

exhibit abnormally positioned wings that look disjointed

(the K-wing symptom).

 A colony may recover from paralysis after a short

time, or the condition may continue for a year or more

without killing the colony. Usually, only one or two colonies

in an apiary will show signs of the disease. Research

has shown that susceptibility to the disease is often

inherited. If paralysis persists, requeen colonies with a

different strain of bees. Adding a frame or two of sealed

brood from a healthy colony to build up the number of

young bees in the diseased colony is also helpful.

 Israeli Acute Paralysis Virus (IAPV)


This new honey bee virus was found in the United States

in 2007 in association with Colony Collapse Disorder

(CCD). IAPV was first described in 2004 in Israel.

Infected bees had “shivering” wings, which progressed to

paralysis, and then the bees died just outside the hive.

 Chilled brood

 If larvae are underfed or the brood covers a larger area

than the bees can keep warm, some of the brood will

die. Uncapped brood killed by chilling turns gray and

resembles sacbrood. Bees will remove such brood from

the cells as soon as the colony grows stronger and returns

to normal. Prevent the loss of brood from chilling

or lack of food by taking the following precautions: (l)

work with the bees as little as possible when the weather

is cold; (2) replace combs in the same order in which

they were removed, especially if the colony is weak and

it is early spring; and (3) do not leave frames of brood

standing outside the hive any longer than necessary.

 Dysentery/spotting on hive

 Dysentery, a diarrhealike condition, is a symptom caused

by the buildup of an excessive amount of fluid in the bee’s

gut and the inability of the bee to retain waste products in

its body as it normally does. Unable to wait until cleansing

flights are possible, these bees void their feces on the

combs, in front of the hive entrance, and on the exterior of

the hive. Factors leading to this situation include nosema

disease, prolonged confinement during winter, and early

spring consumption of food with a high water content.

Colonies located in moist areas or areas with poor air

drainage may often exhibit signs of dysentery. To prevent

dysentery, make sure hives are well ventilated and stocked

with high-quality food. If fall feeding is necessary, be sure

to do it early enough so the bees can properly ripen their

stores. Hives should be rainproof and situated in a dry

location. Good air circulation is important.

 Pesticide kill

 Pesticide poisoning of honey bees can be a serious

problem for beekeepers, especially near areas of intensive

agricultural crop production or when serious pest

outbreaks warrant increased pesticide applications.

Pesticides can have lethal or sublethal impacts on bees.

Some pesticides necessary in crop production are toxic

to honey bees. Colonies may be completely destroyed

by a pesticide, but more commonly only field bees are

killed. Large numbers of dead bees (sometimes piled)

around the outside of the colony are characteristic of

a pesticide kill. Sublethal pesticide kills are difficult to

diagnosis. Colonies exposed to pesticides that do not

kill bees outright may be more susceptible to disease,

have difficulty replacing aging queens, and/or be less


 Winter kill/starvation

 Overwintering colonies sometimes run out of honey or

the cluster is positioned so that the bees cannot reach

the honey, and the bees starve to death. This is characterized

by large numbers of dead bees piled on the bottom

board and/or a cluster of dead bees found with their

heads in the cells. Mold may be evident on the comb

from decaying brood and/or adult bodies.


 Colonies will sometimes rob one another of honey.

This happens particularly when there is no nectar flow

or when honey is being removed by the beekeeper.

Typically, stronger colonies will rob weaker colonies,

but in some cases even strong colonies can be robbed

out. Robbing behavior is characterized by large numbers

of bees clumping on the outside of a colony seeking

entry at various sites and the bees being more aggressive

in general.


 Paralysis is a symptom of adult honey bees and is

usually associated with viruses. Two different viruses,

chronic bee paralysis virus and acute bee paralysis virus,

have been isolated from paralytic bees. Other suspected

causes of paralysis include pollen and nectar from plants

such as buttercup, rhododendron, laurel, and some species

of basswood; pollen deficiencies during brood rearing

in the early spring; and consumption of fermented

stored pollen.

 Laying workers

 On occasion, a colony that is attempting to replace its

queen due to swarming, supersedure, or emergency loss

will not be successful. In the absence of the queen and

capped brood in the colony, some workers will begin to

lay eggs. Eggs produced by laying workers are easy to

distinguish from normal queen-laid eggs. Typically, many

eggs are laid per cell and not positioned in the bottom

of the cell. Colonies in this condition are termed “hopelessly

queenless” and will not rear new queens, even

after receiving a frame of young brood or accepting an

introduced mated queen.

 Colony Collapse Disorder (CCD)

 Colony Collapse Disorder is the name given to colonies

that die exhibiting the following symptoms: (1) the rapid

loss of adult worker bees from affected beehives, resulting

in weak or dead colonies with excess brood present

relative to adult bees; (2) a noticeable lack of dead worker

bees both within and surrounding the hive; (3) the

delayed invasion of hive pests (e.g., small hive beetles

and wax moths) and kleptoparasitism from neighboring

honey bee colonies; and (4) the absence of varroa and

nosema loads at levels thought to cause economic

damage. CCD can cause large-scale wintering losses.

 Skunks and opossums

In some locations, skunks, opossums, and occasionally

raccoons are serious threats to successful beekeeping

because they hamper the development of strong

colonies. Being insectivorous (insect eating), skunks will

raid bee yards nightly, consuming large numbers of bees.

Although such attacks are most common in the spring,

they can also occur throughout the summer and fall.

Field symptoms

 Indications of skunk feeding at hive


 To capture bees, skunks scratch at the hive entrance

and eat the workers when they come out to investigate

the disturbance.

 Indications of skunk feeding at hive

Skunks also leave behind small piles of chewed-up

bee parts. The skunk chews the bees until it consumes

all the juices and then spits out the remains, which

resemble cuds of chewing tobacco. Opossums and

raccoons sometimes attack an apiary in a similar manner

and cause damage similar to that of skunks. The

feces of these animals also contain large numbers of

honey bee exoskeletons since animals cannot digest

this material.

 Elevated hives

 Strong bee colonies sometimes put up a good fight

against skunks and other hive visitors, but weaker

colonies usually fall victim. Maintaining strong colonies,

therefore, is a partial deterrent to animal predation.

One method to discourage predators is to attach

screens or queen excluders to the hive entrance.

These devices hamper the skunk’s efforts to scratch at

the entrance. Elevating the hives on blocks or stands

may help by making the skunk’s belly vulnerable to

stings. Fencing the bee yard with a low fence is an effective,

but more costly, technique. Moving your bees

to a new location is another option.


 Bears are a serious threat to beekeeping operations because

they do a great deal of damage to hives and equipment.

They normally visit apiaries at night, smashing

the hives to eat brood and honey. Once bears locate an

apiary, they return again and again, and controlling their

marauding behavior becomes exceedingly difficult.

 Wax moths

 Two species of wax moth attack hive products: the greater

wax moth, Galleria mellonella, and the lesser wax moth,

Achroia grisella. Of the two, the greater wax moth is considered

the most destructive. Larvae of this moth cause

considerable damage to beeswax combs left unattended

by bees. Beeswax combs in weak or dead colonies and

those placed in storage are subject to attack. Wax moths

pose a continuous threat, except when temperatures

drop below 40°F (4°C).

 Adult wax moths

 Adult female wax moths fly at night and deposit

masses of eggs on unprotected beeswax combs and

in the cracks between hive bodies. After a few days,

these eggs hatch. The larvae crawl onto the comb

and begin feeding in protected areas, often near the

center midrib of the cells. They spin silken galleries for

protection from bees, which will remove the wax moth

larvae if they get the chance.

 Damaged combs showing silken galleries

 Wax moth larvae damage or destroy the combs by

chewing through the beeswax cells as they feed on

bee cocoons, cast skins, and pollen. Initially, only a

few silken galleries will be seen, but within in a short

time, beeswax combs are often reduced to a mass of

webs and debris. Wax moth larvae seldom attack new

beeswax combs or foundation, and they will not feed

on blocks of pure beeswax, candles, or other such

items made from beeswax.

 Cocoons attached to frames

 When fully grown, the wax moth larva spins a rough

silken cocoon, which is usually attached to a frame or

the inside of the hive. The larva frequently cements

the cocoon inside a boat-shaped cavity chewed into

the wood. Chewed wooden frames are weakened and

easily broken. Within the cocoon, the larva changes to

the pupa and overwinters in the pupal stage. Under

warm conditions, adults may emerge at almost any

time of year.

 Strong colonies

 The best defense against wax moths is to maintain

strong, healthy colonies. Strong colonies can defend

themselves against wax moths, whereas weak colonies

cannot. Comb honey and equipment stored off

colonies must be protected from this pest. During the

winter, store honey and brood combs in an unheated

shelter to prevent wax moth damage. During periods

when wax moths are problematic (summer and fall),

store honey supers, brood combs, and comb honey in

a freezer or exposed to light twenty-four hours a day.

 Hive beetles

 The small hive beetle (Athina tumida), North America’s

newest beekeeping pest, was first identified in Florida in

the spring of 1998. This pest originated in Africa, where it

is not considered a serious pest. Some U.S. beekeepers

experiencing heavy infestations, however, have blamed

it for the quick collapse of colonies. The beetle also defecates

in the honey, causing it to ferment and run out of

the combs. Most vulnerable are weak hives with stored

honey or full honey supers either in storage or above bee


 Life history

 Adult hive beetles

 The adult beetle is small (about one-third the size of

a bee), black, and covered with fine hair. Adult beetles

are good fliers and can travel long distances. When it

finds a honey bee colony, the beetle lays its eggs on or

near beeswax combs.

 Masses of small hive beetle larvae

 The eggs hatch, producing masses of small larvae

similar in appearance to wax moth larvae. The larvae

consume pollen and comb but will also eat eggs and

young larval honey bees. After completing the larval

stage, they crawl out of the hive and pupate in the

soil. Areas of the country with sandy soils appear

to be most suitable for successful small hive beetle

pupation and reproduction.

 Comparison of beetle and wax moth larvae

 You can differentiate the hive beetle from wax moth

larvae by examining their legs. Both species have

three sets of legs just behind the head, but small hive

beetle larvae lack the series of paired prolegs that run

the length of the wax moth larva’s body.

 Signs of small hive beetle damage

 Adult beetles can sometimes be observed in cracks

and crevices within a bee hive. Small hive beetle

damage by larvae can often first be noticed by looking

at the bottom board. Heavily infested colonies often

have fermenting honey leaking from their entrances.

While it seems unlikely that small hive beetles actually

kill colonies, weak colonies are often overrun by

the larvae in a very short period of time.

 Cultural control

 Strong colonies

 The best defense against hive beetles is to maintain

strong, healthy colonies. Strong colonies can defend

themselves against this pest, whereas weak colonies

cannot. In areas where this pest is found, honey

removed from colonies and stored for extracting must

be protected by extracting immediately or storing at

low humidity (less than 50 percent).

 Bee louse (Braula coeca)

 Braula coeca, commonly known as the bee louse, is actually

a wingless fly. The adults are small (slightly smaller

than the head of a straight pin) and reddish brown in

color. Although several adult flies may live on a queen,

usually only one will be found on a worker. These pests

do little harm, and because they are susceptible to

treatments for parasitic mites, Braula coeca are found only

rarely in colonies today. A casual glance, however, may

lead one to mistake Braula for varroa mites because they

are so similar in color and size. Braula coeca have six legs

while varroa mites have eight.

 Life history

 Braula move rapidly over the body surface of adult bees,

settling on the dorsal surface at the junction of the bee’s

thorax and abdomen. They remain there until a hunger

response causes them to crawl up to the bee’s head

near its mouthparts. This movement seems to cause the

bee to regurgitate a drop of nectar. The bee louse then

inserts its mouthparts into those of its benefactor and

takes its food. The louse lays its eggs on the cappings

of honey storage cells from May through July. Upon

hatching, the young burrow into the cappings. The larva

pupates inside the tunnel. Soon after emergence, the

young adult crawls onto a bee.

 Field symptoms and diagnosis

 Bee louse tunnels under honey cappings

 As the larvae grow, their tunnels lengthen and broaden.

These tunnels are symptomatic of the presence of

immature Braula. The tunneling larvae can damage the

appearance of comb honey.

 Queen with attached Braula

 If present, Braula adults are often found on queens,

but their damage to a honey bee colony is minor.

The amount of food taken by the larvae and adults is



Honey Bees

 Apis mellifera scutellata

 African bees are the subspecies or races of Apis mellifera

that evolved long ago under tropical and subtropical

conditions in Africa. The original Africanized honey bee

was the hybrid resulting from the cross between African

and European honey bees. This cross was accidentally

released from a bee breeding study in Brazil in the 1950s

and since has spread throughout most of South America,

Central America, and Mexico. It moved into Texas in

1990 and continues to spread in southern states.


 The spread and current range of the Africanized bee

in the United States can be viewed at

Research/docs.htm?docid=11059&page=6. The eventual

range to which these bees will extend is unclear;

however, considering the negative impact stinging

incidences can have on the beekeeping industry, all beekeepers

should be on the lookout for possible behaviors

and traits that may be evidence of Africanized stock.

Africanized and European bees are nearly identical

in appearance. The only way to be sure which strain of

bee is in a hive is to perform morphometric or genetic

testing on a sample of bees. However, Africanized honey

bees demonstrate several behaviors that may help in

selecting colonies that should be sampled. None of

these traits on their own should be used for diagnosis.

 Field symptoms


 The successful spread of Africanized bees across the

Americas is in part due to their high rate of reproduction—

they swarm far more frequently than European

bees. Africanized bee colonies will often rear numerous

swarm cells, and on occasion several virgin

queens can be found in a colony at the same time.

Africanized colony swarms tend to be smaller and

much more numerous than swarms from European

races of honey bee. The cavities in which Africanized

honey bees swarms settle also tend to be smaller than

European honey bees would accept. Africanized bee

colonies can be found in closed BBQs, upturned plant

pots, and used rubber tires.

 Colony usurpation

 Another behavior that has contributed to the successful

spread of Africanized honey bees is referred to as

usurpation. This occurs when a small swarm of bees

settles on the front of a European colony. The swarm

of bees, with its accompanying queen, then moves

into the colony and kills the original queen, and the

Africanized queen takes over. Queenless colonies are

particularly susceptible to usurpation.


 Africanized honey bees, sometimes referred to as

“killer bees,” are notorious for their defensive behavior.

While defensiveness can vary, Africanized bees

are much more sensitive to the alarm pheromone.

Once the pheromone is released, individuals within

a colony or from other colonies within an apiary are

very likely to respond. Attacking bees will often pursue

individuals for a quarter mile or more. If you are attacked,

cover your face, run, and get inside.

 Brood pattern

 The typical brood area on a frame in European colonies

is surrounded by a ring of bee bread and honey,

with the capped and uncapped brood in the center.

Africanized honey bees sometimes fill brood frames

wall to wall with brood, leaving little room for honey

or pollen to be stored at the frame’s edge. They tend

to collect more pollen and use a higher percentage of

comb cells for brood rearing.

 “Runny” behavior

 When examining an Africanized honey bee colony,

the bees will often run excessively on the combs and/

or fly from the frame in large numbers. A ball of bees

hanging from the lower frame edges and a lack of bees

covering brood is distinctive. This behavior additionally

makes finding Africanized honey bee queens

particularly challenging.

 Cultural control

 If colonies exhibit the characteristics above, requeening

with European stock is highly recommended. Maintaining

gentle, manageable stock is especially important in

populated areas.


Forage in Almonds - Why It Matters


The 2019 growing season is upon us. This time of year is eagerly awaited by everyone involved with agriculture.  In particular, the short 4-6 week window of almond bloom is a critical time in which growers and beekeepers need the strongest, most populous hives available. When February and March are cold, overcast and rainy the need is even greater due to reduced flight hours.  If each day of bloom has only a few hours of ideal conditions for bee flight, hives with a greater number of bees are especially important because they send out more foraging bees in that window, and can still get the job done. Blooming cover crops mixes, like the ones provided by the Seeds for Bees® program, do an excellent job of boosting the pollination potential of each hive by increasing the duration, diversity, and density of available nutrition. 


Many producers see cover crops playing a significant role in helping them achieve their goals of improving soil quality, pollinator health and economic viability.  Participants in the Seeds for Bees® program now realize having blooming cover crops before and during the bloom of their cash crop creates a positive feedback loop within the hive.  This positive feedback loop helps ensure healthy bees for pollination.  As pollen is brought back to the hive, the queen lays eggs.  In three days, the eggs hatch into larvae.  The immature larvae, what beekeepers call ‘brood’, secretes a pheromone that drives adult foragers to go find more protein, in the form of pollen.  The smell of the brood pheromone is the hive’s way of communicating the urgency in which bees need to collect resources to support the next generation of bees.  As an example, researchers from Oregon State University gave hives synthetic brood pheromone, and observed more flower visitations and higher yields in hybrid carrot seed production than hives without the pheromone.1  Preliminary results from an Almond Board of California funded study conducted by Dr. Elina Niño displays the impact this phenomenon has on Seeds for Bees cover crops in or near almond orchards.2  She found that hives in orchards with access to the PAm Mustard Mix were on average three frames more populous than hives without access to supplemental forage. Enrolling in the Seeds for Bees® program and planting bee forage cover crops is a great way to get more brood pheromone in the hives you rent for pollination, giving them a boost before the bloom.    

As almond growers are finding it increasingly difficult to get beekeepers with reliably strong colonies, beekeepers are facing greater challenges to keep their hives alive.  Varroa mites and loss of habitat/poor nutrition are two of the biggest health threats honey bees face in modern beekeeping.  To help mitigate other stressors to their bees, beekeepers often look for orchards with supplemental sources of forage for their bees. Planting cover crops that will bloom before and after almonds can help growers attract high-quality beekeepers with healthy hives.  Some beekeepers even give growers a discounted rental rate for hives if there is access to supplemental sources of food.  In order to ensure pollination security now and into the future, beekeepers and growers must work together to find solutions and overcome challenges.  Seeds for Bees is a solution that benefits both. 

Benefits of Cover Crops 

Enhances Honey Bee Health and Vitality 

Improves Soil Health 

In 2018, the National Honey Board, The Almond Board of California, Project Apis m., and Collaborate up united to illuminate the symbiotic relationship between honey bees and the agricultural industry in the inspiring new documentary “The Job Swap Experiment.” The film puts almond growers and beekeepers in each other’s shoes, offering a firsthand look at what each industry does to protect bees. The film features growers, beekeepers, crop advisors and hive management advisors, who use their expertise in insects to provide insight into pollinators and all that they do for our food. Visit:, or the National Honey Board’s YouTube channel to view this film.   
If you have any questions, please visit or call Billy Synk at (916) 287-3035. He will gladly answer questions about the enrollment process and give management advice throughout the life of the cover crop.  

  1. Sagili, R. R., Breece, C. R., Simmons, R., & Borden, J. H. (2015). Potential of Honeybee Brood Pheromone to Enhance Foraging and Yield in Hybrid Carrot Seed, HortTechnology hortte, 25(1), 98-104. Retrieved Jan 23, 2019, from
  2. Niño, Elina (2016-2017) Longitudinal Evaluation of Honey Bee Colonies on Different Forage Regimes. Almond Board of California Annual Research Report 


University of California To
Measure Economic Impact
of Honey Industry

Industry can promote its economic contributions – but only if beekeepers, importers, packers and processors participate in study



FREDERICK, Colo. (May 16, 2018) – From beekeepers and honey importers to packers and processors, the honey industry plays a unique and vital role in the U.S. economy.  To illustrate the industry’s true impact, the University of California is asking business owners to complete a short survey. The questionnaire will measure the economic impact of all aspects of the honey industry by calculating the number of jobs the industry creates and its total economic activity.

The questionnaire’s data will be used to create a final report that showcases the role of the honey industry in the broader U.S. economy as well as its impact on regional economies throughout the country.

To accurately assess this large and varied industry, the University of California is looking to the businesses that make up the honey industry to take part in the questionnaire. The information will be entirely confidential, with the survey conducted online through a secure form without personally-identifiable information. Participants have until Friday, June 15, 2018 to complete the survey.

“The University of California Agricultural Issues Center at UC Davis is committed to helping agricultural organizations better understand their economic impact,” said Project Scientist Dr. Bill Matthews. “We’re looking forward to quantifying the honey industry’s important role within the U.S. economy.”

To participate in the U.S. Honey Industry Impact Questionnaire, please visit the
US Honey Economic Impact Surveybefore June 15, 2018.

“The honey industry makes significant contributions to the US economy,” said Margaret Lombard, CEO of the National Honey Board. “Finally being able to quantify our impact the way other industries have will allow us to generate goodwill for our industry’s many contributions.”

To learn more about the University of California Agricultural Issues Center at UC Davis, please visit For more information on the National Honey Board, please visit



What Gives Bees their Sweet Tooth?



Scientists have discovered bees linger on a flower, emptying it of nectar, because they have sugar-sensing taste neurons which work together to prolong the pleasure of the sweetness.

Newcastle University researchers report that the bees' taste neurons found on their proboscis - their mouthparts - fire intense signals for up to 10 seconds - much longer than the taste neurons found in other insects. Bees visit flowers to obtain nectar, which they eat to feed their colony and to fuel their flight. Bees can taste sugars on their proboscis and when in contact with food, taste neurons on the proboscis are activated signaling the presence of food.

Publishing in Current Biology, the researchers report that the neurons that specifically respond to sugar exhibit a very intense activation, which persists up to 10 seconds. While these neurons exhibit intense activity, the bee will remain feeding at the same sugar source. Only when this activity declines, does the bee remove its proboscis to enable it to try a further feeding point.

Geraldine Wright, Professor of Insect Neuroethology, explains: "We demonstrate in bees that, like in humans, the first taste of something sweet such as a lollipop is incredibly intense but then becomes less interesting. This is so our sensory neurons don't get overloaded and burn out.

"What we've found in bees is that the initial intense sweetness of sugar can last up to 10 seconds - so they will stay on the same sugar source. This makes sense if you think a worker bee is not just collecting for its own use but is storing it for others in the hive. It also means the bee will find a flower and drink all the nectar before other bees can intervene and take it."

Discovery of Two Neurons
The team found that the bee has two taste neurons within each 'taste bud' which interact to enable this persistent, intense sugar neuron activity. Lead author, Newcastle University PhD student Ashwin Miriyala said: "Other insects have one type of taste neuron that is activated by sugars. We have discovered however, that bees have two different types of sugar-activated neurons.

"The first neuron exhibits intense activity when in contact with sugar. The second neuron intermittently inhibits the activity of the first neuron for short durations of time. This inhibition allows the first neuron a sort of 'resting period', so it can recover and maintain its intense activity for longer periods of time.

"Our data show that the interaction between these two sugar neurons is a result of electrical connections between them. This is the first evidence for this kind of connection in any insect taste neuron."

The work was funded by the Leverhulme Trust and the BBSRC and following these findings, the Newcastle University team intend to carry out further research investigating how the bee's sense of sweet taste might be interrupted by pesticides.

REFERENCE: Burst firing in bee gustatory neurons prevents adaptation. Ashwin Miriyala, Sébastien Kessler, F. Claire Rind and Geraldine A. Wright. Current Biology