The use of Lactic Acid in the Treatment
of Honey Bees against the Varroa Mite
Margaret Cowley, MSc
This organic acid can be used as part of your Integrated Pest Management (IPM) regime
LACTIC ACID is one of three organic acids which can be
used to kill varroa mites. The other two are formic acid
and oxalic acid. Formic acid can penetrate brood cells
but it is difficult to control its application which has
resulted in queen and brood loss. It is also highly
corrosive and dangerous to the beekeeper. Oxalic acid
is effective in broodless conditions but it has also been
reported to cause colony weakness and is poisonous to
humans by ingestion.
The organic acids are substances which occur naturally in yel
biological systems and degrade quickly. This means that woC
tethey do not persist as some synthetic compounds do. Lactic r
agr
aacid, as its name suggests, is found in milk, yoghurt and M
cheese. Because it is approved for use in food, it is added This monitoring tray was clean and empty before lactic acid
to products such as olives as a preservative. It occurs treatment. Many hundreds of mites have dropped down the
naturally in honey at a low level. day after through the open mesh floor
IS IT LEGAL? 5 Spray the bees with a fine mist of the 15% solution. Do
not soak them. Avoid spraying open brood. Use 5 mlAs lactic acid is a simple, naturally occurring compound, it
per side of each frame occupied by adult bees. If youis unlikely that any company will go through the expensive
are using large frames such as Langstroth orprocess of registering it as a miticide. For this reason lactic
Commercial, you may need 8 ml per side.acid is not authorised in any European Union member state
but its ability to kill mites without harming bees, its 6 Collect the mites which die over the next day or so
using a tray under the mesh floor. biodegradability and its lack of harmfulness to humans has
led to it being widely used. 7 Examine the tray to see how the treatment has worked.
8 Record the treatment on your record of medications.HOW TO APPLY LACTIC ACID
BROODLESS COLONIESLactic acid is usually supplied in bottles at 90%
concentration. If your varroa monitoring has revealed that Lactic acid does not penetrate sealed brood so any varroa
treatment is needed, follow these steps: under the cappings will not be killed. For this reason this
method is most effective when there is little or no sealed1 Save a good household spray bottle which delivers a
brood. This could be in autumn or winter, or when anfine spray. When it is empty, wash it very thoroughly,
artificial swarm or nucleus without brood has been madeincluding the spray mechanism. Work out how many
up. Research has shown that the efficacy of lactic acidsqueezes deliver 5 ml by spraying into a jug then
solution can be as high as a 90% kill of varroa.pouring the water into a cough medicine measure.
2 Place 50 ml of water into the spray bottle. If it is used on colonies with sealed brood, the treatment
can be repeated after a few weeks to kill those varroa mites 3 Wear eye protection and rubber gloves as the 90%
which have emerged in the interim.solution usually sold is a strong acid which is irritating to
eyes and skin. Measure out 10 ml of this solution and The total quantity of lactic acid used per hive is about 9 grams.
pour it into the spray bottle containing the water. This Although this is unlikely to be harmful (a pot of yoghurt contains
gives 60 ml of 15% solution, enough to treat one colony. about 2 grams of lactic acid) it is good practice only to apply the
4 Choose a day when the temperature is above 7 °C and treatment when the supers are off the hive. Research has shown
there is no wind. Treat either in the morning or in the that the lactic acid content of the honey in treated hives does
evening when the bees are not flying. You are aiming to increase, but that it subsequently degrades completely in the
spray all the adult bees. next seven to eight weeks. z
Bee Craft digital December 2008 Page 27
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32