Using Formic & Oxalic AcidsUsing Formic & Oxalic Acidsfor treatment of Varroa & Trachealfor treatment of Varroa & Tracheal

& Honey bee parasitic mites& Honey bee parasitic mites

Michael YoungMichael YoungInstitute of Northern Ireland Beekeepers Institute of Northern Ireland Beekeepers

Oxalic acid in natureOxalic acid in nature

Occurs naturally in plantsOccurs naturally in plants

Carrots contain 500 mg/kgCarrots contain 500 mg/kg Broccoli contains 900 mg/kgBroccoli contains 900 mg/kg Rhubarb leaves Rhubarb leaves Occurs naturally in insects.Occurs naturally in insects.

Oxalic acid in honeyOxalic acid in honey

Natural constituent of honeyNatural constituent of honey Values range between 8 and 300 Values range between 8 and 300

mg/kg in honeymg/kg in honey Moist vegetables contain much more Moist vegetables contain much more

OA than honeyOA than honey Low risk of residues in honey.Low risk of residues in honey.

Bernardini and Gardi 2001

Oxalic acid use in EuropeOxalic acid use in Europe

Recently registered (2005) and Recently registered (2005) and extensively used in Europeextensively used in Europe

Maximum residue limits established Maximum residue limits established Dec. 2004 at 50 millequivalents of Dec. 2004 at 50 millequivalents of free acidsfree acids

If used according to European If used according to European recommendations, there is no risk of recommendations, there is no risk of problems with honey.problems with honey.

Rademacher and Imdorf 2004

Methods of applicationMethods of application

Oxalic acid is applied by spraying, Oxalic acid is applied by spraying, trickling or evaporatingtrickling or evaporating

Trickling is the preferred application in Trickling is the preferred application in

EuropeEurope

Effectiveness greater than 90%Effectiveness greater than 90%

• Mechanism of acaricidal action has not Mechanism of acaricidal action has not been investigated in detail.been investigated in detail.

Rademacher and Imdorf 2004

Trickle methodTrickle methodTrickling a solution of water-sugar-oxalic acid is a promising method to keep Varroa levels down.

100 parts water and100 parts sugar by weight75 g Oxalic-1 liter water- 1 kg sugarwill make 1,66 liter solution that is enough for 50 hives.

This mixed up solution will keep for a few weeks only and should be used at once. Use 20 to 35 ml solution for each hive depending on the size of the treated colony.

Easy AccessEasy Access

                                       

          

                                       

          

On a 2 box hive the solution is distributed according to the amount of bees in each box. The top box normally holds more bees and is given 70% of the solution

The bottom box is given 30% of the total solution.

The solution is distributed evenly in the gap The solution is distributed evenly in the gap between the top bars, so it will drip down and between the top bars, so it will drip down and

reach as many bees as possible. reach as many bees as possible. (5-6ml between each frame)

Time per hive 1,5 min.Time per hive 1,5 min.

Spray MethodSpray Method

Not necessary to remove individual Not necessary to remove individual framesframes

Spray top and bottom clusterSpray top and bottom cluster

Quick and effective.Quick and effective.

VaporizersVaporizers

Russian Russian GasGas Battery 12voltBattery 12volt

Efficiency from the Oxalic Acid Efficiency from the Oxalic Acid

evaporation in a different dosageevaporation in a different dosage

Test result

Withouttreatment

water Oxalic Acid evaporation (g/Beehive  0,5g       1,0g    2,0g     3,0g 5,0g

Lowest effect 0,0% 1,3% 51,7% 93,2% 91,7% 98,1% 99,0%

Average effect 1,2% 4,8% 82,8% 96,0% 97,2% 99,0% 99,2%

Highest effect 2,7% 11,5% 96,0% 99,2% 99,6% 99,7% 99,8%

Beehives per

test 6   8   12   10   13   11   5

European GuidelinesEuropean Guidelines

Make a solution by dissolving 35g OA in 1 Make a solution by dissolving 35g OA in 1 liter of lukewarm solution sugar water (1:1 liter of lukewarm solution sugar water (1:1 solution)solution)

Recommended dose is 5-6 ml per Recommended dose is 5-6 ml per occupied frame spaceoccupied frame space

Treat in Autumn or early winterTreat in Autumn or early winter Most effective in broodles coloniesMost effective in broodles colonies Treat when temperature. Is 32-55Treat when temperature. Is 32-55°F°F Wear glves and safety gogglesWear glves and safety goggles

The physical propertiesThe physical properties of oxalic acid may be of interest in thisof oxalic acid may be of interest in this

connection. The stuff one buys is usually oxalic acid dihydrate, which is aconnection. The stuff one buys is usually oxalic acid dihydrate, which is acrystal which has two water molecules attached to each oxalic acid molecule.crystal which has two water molecules attached to each oxalic acid molecule.

The CRC Handbook of Chemistry and Physics gives the following propertiesThe CRC Handbook of Chemistry and Physics gives the following propertiesfor oxalic acid dihydrate:for oxalic acid dihydrate:

On heating:On heating:

1) The water of hydration leaves at 101.5 degrees C. The water boils off1) The water of hydration leaves at 101.5 degrees C. The water boils offleaving anhydrous oxalic acid crystals.leaving anhydrous oxalic acid crystals.

2) At 157 degrees C the oxalic acid starts to sublime (goes directly from2) At 157 degrees C the oxalic acid starts to sublime (goes directly fromsolid to gas)solid to gas)

3) At 189 degrees C the oxalic acid which has not yet sublimed decomposes to3) At 189 degrees C the oxalic acid which has not yet sublimed decomposes toformic acid and carbon monoxide.formic acid and carbon monoxide.

Treatment ConsiderationsTreatment Considerations Mix freshMix fresh

Store unused material in refridgeratorStore unused material in refridgerator

Safety equipmentSafety equipment TrickleTrickle Acid resistant glovesAcid resistant gloves GogglesGoggles Spray or fumigationSpray or fumigation As above as well asAs above as well as Acid rated respiratory cartridgeAcid rated respiratory cartridge

ResultsResults Spray treatment reduces varroa Spray treatment reduces varroa

infestation by 92% when compared to infestation by 92% when compared to untreated (mean)untreated (mean)

Trickle treatment reduced varroa Trickle treatment reduced varroa infestation by 87% infestation by 87%

Effectiveness of spray and trickle Effectiveness of spray and trickle treatments are not significantly treatments are not significantly differentdifferent

No Oxalic Acid resistant No Oxalic Acid resistant possible.possible.

It works by destroying the mite's It works by destroying the mite's suction ability, stopping it from suction ability, stopping it from feeding from the bee. Effectively, the feeding from the bee. Effectively, the mite starves to death.  mite starves to death.  

Essential advantages over the Essential advantages over the actual usually fighting methods actual usually fighting methods

are:are: no delays in the honey, beeswax and no delays in the honey, beeswax and

propolispropolis

very good bee compatibility very good bee compatibility 

high degree of effectiveness , high degree of effectiveness , up to 99% up to 99% in brood free coloniesin brood free colonies

no early ageing of the bees (important to no early ageing of the bees (important to population of the bees in spring) population of the bees in spring)

outside any time of honey-collection usableoutside any time of honey-collection usable very user kind for the beekeeper.very user kind for the beekeeper.

Caution: Caution: 

Oxalic acid in its crystalline form is poisonous and Oxalic acid in its crystalline form is poisonous and should be handled carefully. It should not be allowed should be handled carefully. It should not be allowed to contact the skin and it is essential that the dust is to contact the skin and it is essential that the dust is not inhalednot inhaled

Weigh and mix outdoors, preferably in a light breeze Weigh and mix outdoors, preferably in a light breeze to take any dust away from you. In the solution given to take any dust away from you. In the solution given above it is safe to handle with rubber gloves. above it is safe to handle with rubber gloves. 

Oxalic acid is not dangerous if precautions are Oxalic acid is not dangerous if precautions are taken. Wear rubber gloves and be careful not to let taken. Wear rubber gloves and be careful not to let the acid touch your skin or eyes. Wear old clothes, the acid touch your skin or eyes. Wear old clothes, use protective mask, and glasses.use protective mask, and glasses.

Annual Bee meeting YorkAnnual Bee meeting York

Oxalic Acid can only be used by Oxalic Acid can only be used by requiring a prescription from the vetrequiring a prescription from the vet

It can only be used as a hive cleanserIt can only be used as a hive cleanser

All beekeepers have to keep records of All beekeepers have to keep records of all medicines used as a treatment for all medicines used as a treatment for beesbees

If not! It carries a two year jail sentenceIf not! It carries a two year jail sentence

Thank You!Thank You!

Credits Dr Marion EllisCredits Dr Marion EllisNebraska UniversityNebraska University