Orange Blossom Beekeepers Association

Monthly Meeting: Feb 16, 2023

OBBA Announcements

What's the buzz?

OBBA Workshop

Saturday, Feb 25, 2023 (tentative)

Florida Conference United Church of Christ 9300 University Blvd, Orlando, FL 32817

Honey Bee Day

Help the Orange Blossom Beekeepers Association Organize and Implement a National Honey Bee Day Celebration at the UF Extension Conway location on Saturday, August 19, 2023

How do you envision a perfect National Honey Bee Day? We'd like to know and we'd like your help!

Planning will start in March!

Honey Bee Day

February / March Bee Management

Current UF Management Recommendations (February/March)

Colony populations begin to grow (late Feb into March!)
- Remedy failing queens as necessary
- Add supers and/or swarming control
- Make nucs/splits
Monitor for Varroa
- Treat if 3%
Check for AFB and/or EFB

What is blooming in Central Florida (February)

Cherry
Fetterbush
Hawthorn
Maple
Oak
Plum
Sand Pine

Swamp Titi
Sweet Clover
Water Viburnum
Willow

What is blooming in Central Florida (March)

Blueberry
Cherry
Fetterbush
Hawthorn
Oak
Orange

Plum
Spanish Needle
Sweet Clover
Water Viburnum
Willow

Varroa destructor Control

An Integrated Pest Management Approach

Why control Varroa?

Can cause colony death between 6 months to two years
Associated with 6 different honey bee viruses:
- Deformed wing virus
- Acute paralysis virus
- Sacbrood virus
- Israeli acute paralysis virus
- Kashmir bee virus
Responsible beekeeping
Keeping healthy honey bees can help keep healthy pollinator populations

Varroa mites

Jumped from the Asian honey bee (Apis cerana) to the European honey bee
Spread around the World (Arriving in USA in 1987)
Reproduce in cells with developing workers and drones
Feed from the fat bodies of the bees and larvae
Controlling varroa = controlling viruses

Drone brood cells are larger and the post-capping stage is longer (15 days for drones versus 11 days for workers), which allows the mite to produce more offspring per cycle. Varroa mites do not reproduce within queen cells because of the repellency of royal jelly and the very short post-capping period of queens (7 days).

When honey bee brood is present in the colony, the majority of varroa mites are in the capped brood reproducing where they can often escape chemical treatments.

Viral titers in honey bees are correlated with varroa mite load, with both rising from spring to fall. Thus, the control of the mite population is a method of controlling viruses. In beekeeping operations, timing of mite control is critical; controlling mites in the fall is a major factor linked to overwintering survival in honey bees.

Four Population Phases of Honey Bee and Varroa

Integrated Pest Management (IPM)

IPM is the recommended approach
Relies on a combination of different control methods:
- Genetic
- Cultural
- Chemical

Beekeepers can use an integrated pest management (IPM) approach in which they use several different mite control techniques in combination or in rotation throughout the year. A combination of various treatment protocols is effective and it reduces the likelihood that resistance to chemicals will develop, as happens when only one treatment method is used repeatedly.

Repeatedly using the same treatment for Varroa can increase the likelihood of mites developing resistance.

To prolong mite population build up, beekeepers should introduce resistant or tolerant genetic stock and use cultural methods. Should mite levels ever reach or exceed the treatment threshold, beekeepers should apply an appropriate chemical treatment.

Photo: https://extension.psu.edu/methods-to-control-varroa-mites-an-integrated-pest-management-approach

Old photo:

Checking mite levels

Do this regularly
Methods:
1. Alcohol washes
2. Sugar rolls
3. Sticky board
Goal: <3%

Alcohol washes are the most accurate method for monitoring mite populations, for apiaries with a large number of colonies sampling 20% of the colonies will provide sufficient information about mite populations.

Economic or action thresholds vary but are aimed at keeping mite levels below or around a mean abundance of 2 mites per 100 bees.

Suggested monitoring schedule for Osceola County, FL:

February (jar method of sampling)- so you can treat if necessary before placing honey supers.
June (sticky board)
July- (sticky board) right after harvesting spring honey, so you can treat if necessary, before placing honey supers for the fall nectar flow. Mite populations are rapidly increasing during this time.
August (sticky board)
September (sticky board)-right after harvesting fall honey.
November (jar method of sampling)

Alcohol Wash Method

Use a wide-mouth glass jar with 50 ml (2 oz) of rubbing alcohol
Scoop about 300 bees (1 cup) from the brood area
- NO Queen!
Shake for several minutes
Pour contents through a light metal wire-mesh screen
Count number of mites (divide by 3 for a %)

Genetics

Queen selection:

Choose new young queens
Local survivor colony queens and Ankle biters/leg chewers queens
Specialty queens
- Russian
- Varroa Sensitive Hygiene (VSH)
- Caucasian hybrid
- Buckfast hybrid
- Buckfast
- Improved Carniolan stock

Some of the more exciting advances in varroa mite control has been in honey bee genetics. In recent years, much work has been done with the development of particular strains of honey bees that have shown tolerance to the varroa mite. Though the mechanisms are not completely understood, some behavioral and physiological traits likely play a role in varroa resistance. Today, several strains of bees are available that have been shown to reduce the number of varroa mites within their colonies.

Russian strain. Researchers at the USDA Honey Bee Research Lab in Baton Rouge, Louisiana have imported bees from the Primorsky region in far-eastern Russia because they co-exist with the original host species of varroa (the sister honey-bee species, Apis cerana). Because these Russian bees have been exposed to the mite for a longer period compared to other strains, it follows that they may have developed a resistance to the mite. Indeed, research has shown that they are over twice as resistant to varroa as other commercial stocks. Moreover, for reasons that are yet unclear, this stock appears to be highly resistant to the tracheal mites, a second parasitic mite that infests honey bee colonies. The Russian strain has been made available for commercial purchase in the U.S. after a protracted period in quarantine.
- Russian bees inhibit mite reproduction. Russian bees have a slower varroa mite population increase than other bees, due to an ability to suppress mite reproduction. Russian bees have lower percent brood infestation and fewer multiply-infested cells, and bees inoculated with the mite-vectored deformed wing virus exhibit significantly less viral replication.
VSH stock. Standing for Varroa Sensitive Hygiene, this trait was selected for by USDA researchers using classical bee breeding and instrumental insemination techniques. The bees have been selected to detect varroa mites in the cells of developing pupae and remove them before the mites can reproduce. This stock has been crossed with other, more common commercial stocks in an attempt to integrate this useful trait into other bee strains.
Varroa Sensitive Hygiene (VSH) bees can recognize and remove mite-infested pupae. Bees that remove dead brood quickly are hygienic and are thought to be better at removing mites from the hive, as well. Other desirable traits include the recognition by the bees that the mites, themselves, are present and undesirable. This trait is recognized by testing.
Hygienic behavior. Many queen breeders have actively bred for colony brood-nest “cleanliness” or hygienic behavior. Much research has demonstrated lower levels of numerous diseases in colonies selectively bred to uncap and removed diseased or parasitized brood (e.g., the Minnesota Hygienic stock). While these stocks are not immune to varroa parasitism, they may significantly reduce the need for other control methods.
- A more accurate measurement of resistance would be a test of the hygienic behaviour of the colony. For this purpose, covered larvae are pierced with a needle. Subsequently, the removal of the damaged brood by the workers is measured.
- Bees can be partially hygienic, and variable in how they perform in each category. The three abilities are
  - Finding dead or damaged brood quickly
  - Uncapping dead or damaged brood
  - Removing dead or damaged brood from the cells
Ankle biters/leg chewers will bite the mites, harming their bodies and/or legs. This trait is recognized by looking closely at mites that have dropped through a screen onto a sticky board, determining the proportion of the mites that have been damaged by the bees

A Test for Hygienic Behavior

Mark a cell directly above 3 groups of 7 newly sealed cells
Kill all 21 larva by pricking them with a pin through the cappings
- Use the same hole to prick the larva several times at different angles
Count how many cells are completely uncapped and cleaned out after 24 hours
- Colonies which have cleaned 19 cells (90%) are considered hygienic

Cappings of newly sealed brood cells are punctured with a fine pin to kill the larva beneath. After 24 hours, the number of cells uncapped and cleaned out are counted and recorded. After several replications under different environmental conditions, colonies which have cleaned at least 90% of the cells within 24 hours are considered hygienic. This form of hygienic behavior has been shown to be a significant factor in resistance to Varroa, as well as American foulbrood, and especially Chalkbrood.

Mark a cell directly above three groups of seven newly sealed cells. Use a quick drying paint (e.g. Liquid Paper). Also mark the top bar.
Kill all twenty-one larva by pricking them with a pin through the cappings. Use the same hole to prick the larva several times at different angles.
Twenty-four hours later count how many cells are completely uncapped and cleaned out. Colonies which have cleaned 19 cells (90%) are considered hygienic.

Cultural Methods

Take advantage of honey bee behaviors and/or Varroa biology
Goal: To limit the number of mites that reproduce => slowing Varroa population build up

Screened bottom boards

Varroa fall off of bees naturally and when bees groom each other
Allow mites to fall through (out of the hive), preventing them from crawling back up
Passive mite control device
Reported to reduce mite levels by as much as 40%

Sticky Boards

Similar to screened bottom boards -> prevents mites from returning to the cluster
After 3 days, the sticky board is removed:
- Count the Varroa
- Divide by the number of days that the board was under the hive
- If > 40 => treat the colony

Varroa mites cling to their adult hosts and often lose their grip. When mites fall onto the bottom board they will climb up again and return to the bee cluster. The placement of a sticky board on the bottom board prevents mites from returning to the cluster. Sticky boards are commercially available or re-usable sticky traps can be easily constructed at home.
- Varroa fall off of bees naturally and when bees groom each other.A sticky board is placed under the hive will catch these mites that fall off of the bees. After three days, the sticky board is removed; the number of Varroa are counted and that number is divided by the number of days that the board was under the hive (e.g. if left for three days, divide the mite count by three). If the number of mites collected is over 40, the Varroa load is high enough to treat the colony.
- The sticky board sampling method assesses the mite drop from the entire colony but does not tally mites per 100 bees.

Brood interruption or making splits

Interrupting the honey bee development cycle also interrupts Varroa development

Fewer brood cells for mite reproduction
Cage or remove the queen for approximately 3 weeks
All of the brood hatches (mites are forced out of the cells and onto adult bees)
Adult bees increase grooming behavior in the absence of brood
Properly timed, can ease stress of a dearth period

Drone brood removal

Varroa mites prefer drone brood 12x more than worker brood
Removing capped drone brood = removing Varroa
Cut out mostly capped Drone comb 1-3 times
Can reduce by up to 80%

Powdered sugar dusting

Being covered in powdered sugar causes bees to groom themselves and each other -> dislodging mites
Labor intensive and unsure effectiveness

Effectiveness (Cultural Methods)

More Effective

Drone brood removal
Brood interruption
Re-queening

Minimally Effective

Screen bottom board
Comb culling
Powdered sugar
Apiary site
Colony ID/configuration
Basic sanitation

Chemical Control Options in Florida:

Apiguard - essential oil from thyme plant
Api Life VAR - essential oils from thyme, camphor, eucalyptus, mint plants
Formic Pro (replaces Mite Away Quick Strips) - Formic acid
HopGuard II - beta acids from hop plant
Oxalic Acid Dihydrate
Apivar - Amitraz, synthetic chemical, pesticide class: amidine
Apistan - tau-fluvalinate, synthetic chemical, pesticide class: pyrethroid

Natural (Soft Chemicals)

Apiguard (thymol)
- Spring and Fall
- Use these treatments between 60° and 105°F
- Apply in late afternoon or evening
- Don’t apply during nectar flow

Natural (Soft Chemicals)

Api Life Var (thymol, eucalyptor, menthol, camphor)
- Spring or autumn
- Use when temperature is between 65-85°F
- Apply 3 times at 7-10 day intervals
- Remove honey supers during treatment and wait one month following treatment to harvest honey

Natural (Soft Chemicals)

Formic Pro (Mite-Away)
- Use when temperature is between 50-92°F
- Can be used while honey supers are on

Formic acid. The EPA has recently permitted the use of formic acid for the control of varroa mites in the United States. This method has been used by beekeepers in Canada and Europe for many years, and it is the only chemical pesticide that can be used for organic honey production. There are several delivery methods for formic acid, such as placing pads soaked with liquid formic acid on top of the hive (by the trade name Mite-Away II®). The product cannot be used during a honey flow, and the daily high temperatures must be between 50°F and 79°F. If temperatures exceed 82°F during the first week of treatment, it must be removed from the hive as it may result in a significant loss of brood and adult bees. Small colonies (fewer than 6-20 frames of bees) can themselves be overwhelmed by the fumes.

Formic acid. Formic acid occurs naturally in the venom of honey bees and is a natural component of honey. This chemical is commonly used because, at high concentrations, this organic acid penetrates the wax cappings and effectively kills reproducing mites. One limitation is that the use of formic acid is temperature dependent and can cause damage to the colony if used at ambient temperatures higher than 85F because it can increase brood mortality and the potential for queen loss. When used below 50F, formic acid results in low efficacy.

Natural (Soft Chemicals)

Oxalic acid
- Most effective during broodless periods (dormant phase)
- Winter or early spring method
- Should not be used as a stand-alone treatment

Natural (Soft Chemicals)

Hop Guard II (hops beta acids)
- Do not use more than 3 times/year
- Can be used when honey supers are on
- More effective when less brood (does not cross cappings)

Synthetics (Hard Chemicals)

Apivar (amitraz)
- Remove honey supers while treating
- Wait 2 weeks after treatment ends before replacing them
- Do not use this treatment more than 2 times/year
- Some resistance developing

Synthetics (Hard Chemicals)

Apistan (fluvalinate)
- Remove honey supers while treating
- Do not use beeswax for human consumption after treatment
- Daytime temperatures must be at ≥50°F
- Developing resistance

http://sfyl.ifas.ufl.edu/media/sfylifasufledu/osceola/documents/agriculture/varroa-mite-control.pdf

Fluvalinate is the active ingredient of Apistan strips. It is a synthetic pyrethroid applied as a contact miticide. Highly effective during the 1990s, and noted for its low toxicity and ease of application. Controls Varroa mites only; not effective against tracheal mites (Acarapis woodi). Product delivered in an impregnated plastic strip suspended between brood frames. Formulation is not water soluble; no danger of honey contamination. Product is fat soluble and after prolonged use, small quantities will migrate into the wax. Product is applied in early spring or fall, outside the period of honey production. Widely used throughout the world. Illegal formulations, inappropriate applications, under-dosing, reusing old strips, and un-abated use has led to the development of resistant mite strains in North America and Europe. Read label directions closely before use. Note: Fluvalinate-resistant Varroa mites have been confirmed in some parts of the continent. The efficacy of fluvalinate may vary. Advice: Contact your Apiary Inspector for details and recommendations.

Summary Chemical Table

Chemical	Soft/Hard	Temp Req	Leaves residue in honey?	Leaves residue in wax?	Negative impacts to bees?
Apiguard	Soft	60° and 105°F	Yes, but dissipate in weeks; No permanent residue	Yes, but dissipate in weeks; No permanent residue	Reduced queen laying, and increased brood and adult mortality; Risks are greater when used at too high temperatures
Api Life Var	Soft	65-85°F	Low residues within the range of safety; Taints the taste	Yes, but dissipate in weeks; No permanent residue	Can cause bearding, adult irritability, bee mortality. Risks are greater when used at too high temperatures
Formic Pro	Soft	50-92°F	No	No	Can cause queen loss, adult and brood mortality, bearding, and absconding if used at too high temperatures
Oxalic Acid	Soft	No	No	No	Some initial adult kill, and some sub-lethal effects (increased grooming, decreased activity, reduced lifespan)
Hop Guard II	Soft	No	Yes, only in honey in brood chamber; Not in honey supers	Yes, only in wax in brood chamber; Not in honey supers	None reported yet
Apivar	Hard	No	Yes, low levels that dissipate in months	Yes, low levels that dissipate in months	Impaired queen reproduction and increased brood mortality
Apistan	Hard	≥50°F	Yes	Yes	Impaired queen reproduction, brood development, and drone survival

When treating mites

All colonies in an apiary should be treated at the same time with the same chemical or non-chemical technique.

Honeybee Coalition Free Varroa Tool

Integrated Pest Management (IPM)

Control Varroa for healthy bees as a responsible beekeeper
Check Varroa levels regularly
Choose hygenic genetics
Integrate non-chemical treatments to your strategies
- Screen bottom board, brood breaks, drone brood removal, etc
Use chemical treatments as you must, and follow all the application directions

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