Updated: Mar 16
Using Essential Oils for Hive Health
In this article I want to address using essential oils as a natural approach to protecting the health of your colonies from pest and disease.
Beekeepers may choose to use a natural miticide as an alternative to or in combination with synthetic pest control. Over time varroa mites develop a resistance to chemical treatments so this creates a break in the cycle. Using essential oils offers an option free from chemical contamination to the honeycomb. It is also a personal preference using natural or chemical methods.
Essential oils are very potent. Finding the best oil for your colony and how to use it is imperative for the safety of your bees. The oils must be food grade, certified organic. The oils I trust and use are CPTG (Certified Pure Tested Grade) which means there are no added fillers, synthetic ingredients or harmful contaminants in the essential oils that would reduce their efficacy. When using essential oils it is critical to the health of your bees that you are using the correct dosage or your bees could die. Doses are calculated to be lethal to pests, not your bees. Keep in mind that as with the use of essential oils in humans and pets, natural does not mean harmless.
In this article I will discuss the top oils most commonly used by a beekeeper to treat a colony. Lemongrass, spearmint and thyme are used the most. Other oils also used in some recipes may be wintergreen, eucalyptus, peppermint and tea tree.
Lemongrass is probably the most used oil by beekeepers for treatment of varroa and tracheal mites and a preventative measure against Nosema disease.
What makes lemongrass effective is it's anti-fungal and anti-viral properties. Lemongrass can be added to sugar water as a supplement for overall hive wellness. Used in sugar water it can stimulate feeding in spring. and in a spray bottle to calm the bees during a hive inspection rather than a smoker. It can also be used to lure a swarm to a trap as it mimics honey bee pheromones. Because of this Lemongrass oil requires careful use with weak hives. The scent may lure robber bees to the hive and the weak colony is unable to defend itself. It also contains Citral and Geranic acid that are believed to kill honey bee mites.
Thyme oil can also be used in the fight against varroa mites. It blocks the pores on the mite causing confusion. The mite then fall off the honeybee to the bottom of the hive. Using a screened bottom board allows the mite to fall to the ground making it unable to climb back up in to the hive. Thymol is one of the alternative treatments in late summer, or even in spring according to the temperatures of the year or area. Like formic acid, thymol acts by its vapors. The bees distribute them in the hive by their activity, like ventilation or removal of the product. The ideal range for thymol treatments is 20-25°C (68-77°F).
When it is correctly used, thymol is a highly efficient and safe treatment against the Varroa mite. It is important to note that thymol does not reach reproducing Varroa mites in the brood and only kill the mites on the adult bees.
Thyme oil has anti-fungal properties and may be useful for the control of Chalkbrood disease. (beinformed.org)
Spearmint oil works in the same manner as thyme. It masks the natural scent of the bees and makes it more difficult for the mites to locate them. However, this does not interfere with the normal pheromones of the bees which control the activity inside the hive.
Spearmint is also used in conjunction with lemongrass during feeding to improve hive health. A blend of lemongrass and spearmint has been found to help honey bees resistant to the pathogens that may be transmitted by mites.
ESSENTIAL OIL USES
There are several ways to present to the honey bees. Essential Oils mixed with a base of 1:1 sugar syrup fed through the standard hive feeders for syrup is one way.
Grease patties, spread between pieces of waxed paper, may be mixed and placed on the top of the brood frames. Honey bees will throw the waxed paper out the front door, as they consume the Essential oil patty mixture. You can make or purchase this type of patty as they are commercially sold as brood builder patties or winter patties. The advantage to mixing your own is you are in total control of ingredients and will know 100% what is in them.
You can also blend a sugar syrup concentrate with up to four times the normal amount of oils that can be drenched over the bees as a Varroa Mite treatment. Dribble approximately a cup of this mixture over the bees. The honey bees will stop all other activity to clean up the sugary mess. The Honey Bees will then ingest the mixture as they clean themselves and the hive. The bees will also do this if you apply the mixture in a spray bottle during inspection in lieu of a smoker.
They might otherwise ignore the essential oils at this concentration but this method encourages them to consume the treatment as they go about cleaning up. There are reports of this as an effective treatment for heavy varroa mite infestations, though the reports are unscientific and could be considered hearsay. In the end it is up to you to decide if you should pour any liquid over your honey bees. Perhaps the better method is to keep infestations low if possible by keeping the hives strong.
ESSENTIAL OIL TREATMENT
General Purpose Essential Oil Mixture: Homemade Honey-B-Healthy Substitute
5 cups water
2½ pounds of sugar
1/8 teaspoon lecithin granules (used as emulsifier)
15 drops Spearmint oil
15 drops Lemongrass oil
Boil water, dissolve sugar, remove from heat and quickly add lecithin and essential oils. Stir until everything is evenly combined. Hint: put in blender because lecithin can be hard to stir in. The solution should have a strong scent and should not be left open around bees. Cool before using.
Dosage: 1 teaspoon per quart of 1:1 syrup for stimulating brood rearing, pollen collection, and early spring development.
2 teaspoons per quart of 1:1 syrup to improve health, cases of dysentery, chalkbrood, and other stress problems in bees.
4 teaspoons per quart of 1:1 syrup when introducing new queens (you will need to drizzle this over them or they won’t eat it on their own). Do not feed during honey flow if honey is used for human consumption. Useful for building up packages, nucs, and swarms
Feed this, along with other essential oil blends, to both new and existing hives. Begin feeding as soon as the weather is warm enough to fully inspect the hives until a strong nectar flow begins.
Store in the fridge when not using.
Grease Patty (no essential oil)
one part solid vegetable shortening and two parts white sugar.
Mix well until combined, split into ¼ portions and store in freezer between wax paper sheets.
Grease Patty (with essential oil) (by weight)
one pound solid vegetable shortening
three pounds sugar
Mix until combined and store as listed above.
• Add three drops of food grade essential oils to provide odor and to attract the bees.
Scent Masking Syrup
Nearly any essential oils (except Lemongrass) can be mixed with 1:1 syrup to mask undesired scents in the hive. The masking syrup can be used for introducing a new queen or when combining two hives. Add the desired amount of oil to the syrup. (start with one drop at a time)
The stronger the scent the better as it masks odors.
Blend in blender.
I can't stress enough how important it is that you are using certified pure tested grade (CPTG) essential oils with your bees. These oils are very potent and not using the correct dosage could be fatal.
While these products are not a cure for the issues our bees face, they certainly can make a difference and have a positive influence. Always use caution with whatever you use in the hive.