In the past two decades, the parasitic mite Varroa destructor has become increasingly difficult to control with synthetic acaricide chemicals due to genetic resistance. A study conducted in southern England investigated the efficacy of oxalic acid (OA), a natural chemical, in killing phoretic mites on adult worker bees under field conditions.
The study compared three OA application methods: trickling, spraying, and sublimation. Three or four doses (sublimation) were used, with a total of 110 broodless colonies participating in the study in early January 2013. Treatment efficacy was assessed by extracting mites from samples of approximately 270 worker bees collected immediately before and 10 days after treatment.
All three methods demonstrated high varroa mortality, reaching around 93–95% when using 2.25 g OA per colony. However, sublimation was found to be superior, achieving higher mortality at lower doses: 0.56 or 1.125 g per colony (trickling: 20, 57% mortality; spraying: 25, 86%; sublimation: 81, 97%).
Sublimation using 2.25 g of OA also resulted in significantly lower worker bee mortality in the 10 days after application compared to either trickling or spraying. Worker bee mortality rates were 3 and 12 times lower following sublimation, respectively. Additionally, colony mortality four months later in mid-spring was lower in colonies treated via sublimation. Colonies treated via sublimation also had greater brood area four months later than colonies treated via trickling, spraying, or control colonies.
A second trial in December 2013 treated 89 broodless colonies with 2.25 g OA via sublimation to confirm the previous results. Varroa mortality was 97.6%, and 87 (98%) of the colonies survived until spring. This confirms that applying OA via sublimation in broodless honey bee colonies in winter is a highly effective way of controlling V. destructor and causes no harm to the colonies.
The Varrox is the best oxalic acid vaporizer we have researched. We use it to KILL MITES. It's easy to use and works without harming the Queen, Brood, or Adult Bees. Oxalic Acid Vapor kills mites on contact and leaves no residue in the hive. The mites can't become resistant to Oxalic Acid because of the way it works. The vapor is better and easier to use than the Drench Method. Europe and the rest of the world have been using Oxalic Acid Vapor for 20+ years.
It's now legal in the USA! You might find out where you can purchase it on ScientificBeekeeping.com.
Additional Benefits of Oxalic Acid Vaporization:
If you're looking for a safe and effective way to control varroa mites in your beehive, oxalic acid vaporization is an excellent option. The Varrox oxalic acid vaporizer is a user-friendly and efficient tool that can help you keep your bees healthy and productive.
The study compared three OA application methods: trickling, spraying, and sublimation. Three or four doses (sublimation) were used, with a total of 110 broodless colonies participating in the study in early January 2013. Treatment efficacy was assessed by extracting mites from samples of approximately 270 worker bees collected immediately before and 10 days after treatment.
All three methods demonstrated high varroa mortality, reaching around 93–95% when using 2.25 g OA per colony. However, sublimation was found to be superior, achieving higher mortality at lower doses: 0.56 or 1.125 g per colony (trickling: 20, 57% mortality; spraying: 25, 86%; sublimation: 81, 97%).
Sublimation using 2.25 g of OA also resulted in significantly lower worker bee mortality in the 10 days after application compared to either trickling or spraying. Worker bee mortality rates were 3 and 12 times lower following sublimation, respectively. Additionally, colony mortality four months later in mid-spring was lower in colonies treated via sublimation. Colonies treated via sublimation also had greater brood area four months later than colonies treated via trickling, spraying, or control colonies.
A second trial in December 2013 treated 89 broodless colonies with 2.25 g OA via sublimation to confirm the previous results. Varroa mortality was 97.6%, and 87 (98%) of the colonies survived until spring. This confirms that applying OA via sublimation in broodless honey bee colonies in winter is a highly effective way of controlling V. destructor and causes no harm to the colonies.
The Varrox is the best oxalic acid vaporizer we have researched. We use it to KILL MITES. It's easy to use and works without harming the Queen, Brood, or Adult Bees. Oxalic Acid Vapor kills mites on contact and leaves no residue in the hive. The mites can't become resistant to Oxalic Acid because of the way it works. The vapor is better and easier to use than the Drench Method. Europe and the rest of the world have been using Oxalic Acid Vapor for 20+ years.
It's now legal in the USA! You might find out where you can purchase it on ScientificBeekeeping.com.
Additional Benefits of Oxalic Acid Vaporization:
- Effective in broodless colonies
- No harm to bees or brood
- Leaves no residue in hive
- Mites cannot develop resistance
- Proven effective for over 20 years
If you're looking for a safe and effective way to control varroa mites in your beehive, oxalic acid vaporization is an excellent option. The Varrox oxalic acid vaporizer is a user-friendly and efficient tool that can help you keep your bees healthy and productive.
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You can purchase Oxalic Acid Vaporization products at:
Mannlake.com
WHY OXALIC ACID?
European beekeepers, who have been dealing with the varroa mite for much longer than we have, and who often face regulations that restrict the use of chemicals that may contaminate honey, have discovered that varroa is susceptible to organic acids such as formic (found in ants), acetic (vinegar), lactic (milk acid), citric (citrus fruits), and oxalic (found in many plants, including Oxalis). They have conducted extensive research into the effectiveness of each of these acids.
While both lactic acid and acetic acid have shown some effectiveness in killing varroa, oxalic acid has emerged as the preferred organic acid for varroa control. It is approved for use and widely used in a number of European countries, Canada, and New Zealand. However, it is not yet registered for use in the United States. As a result, this article is primarily intended for our international readers and is for informational purposes only for US beekeepers. The American Beekeeping Federation (ABF), led by Troy Fore, has petitioned the US Food and Drug Administration (FDA) for the registration of oxalic acid in sugar syrup, based on research conducted by Marion Ellis of the University of Nebraska.
Oxalic Acid: A Unique Organic Acid
Oxalic acid is unusual for an organic acid, which are typically weak acids, in that it has a very high dissociation constant. This means that it behaves more like a mineral acid, such as sulfuric or hydrochloric acid, than your typical carboxylic acid, such as acetic or citric acid. For instance, you could sprinkle pure crystals of citric acid on your tongue without any serious consequences (they are used to coat sour gummy worms). However, if you were to do the same with oxalic acid, you could burn the skin right off! Oxalic acid is approximately 10,000 times stronger than the acetic acid found in vinegar (vinegar is a 5% solution of acetic acid).
While both lactic acid and acetic acid have shown some effectiveness in killing varroa, oxalic acid has emerged as the preferred organic acid for varroa control. It is approved for use and widely used in a number of European countries, Canada, and New Zealand. However, it is not yet registered for use in the United States. As a result, this article is primarily intended for our international readers and is for informational purposes only for US beekeepers. The American Beekeeping Federation (ABF), led by Troy Fore, has petitioned the US Food and Drug Administration (FDA) for the registration of oxalic acid in sugar syrup, based on research conducted by Marion Ellis of the University of Nebraska.
Oxalic Acid: A Unique Organic Acid
Oxalic acid is unusual for an organic acid, which are typically weak acids, in that it has a very high dissociation constant. This means that it behaves more like a mineral acid, such as sulfuric or hydrochloric acid, than your typical carboxylic acid, such as acetic or citric acid. For instance, you could sprinkle pure crystals of citric acid on your tongue without any serious consequences (they are used to coat sour gummy worms). However, if you were to do the same with oxalic acid, you could burn the skin right off! Oxalic acid is approximately 10,000 times stronger than the acetic acid found in vinegar (vinegar is a 5% solution of acetic acid).
COMMON OXALIS SP.
Oxalic Acid: A Natural Defense Mechanism in Plants
Most kids are familiar with the sour taste of flower stems, which is caused by oxalic acid. Oxalic acid is a common organic acid found in many plants, serving as a natural defense mechanism against herbivores. It works in several ways:
Due to its natural occurrence and relatively safe handling, oxalic acid gained traction as a potential mite control agent for honeybees:
[1] USDA National Nutrient Data Laboratory (2015). Oxalic Acid in Foods. Retrieved from: https://www.nal.usda.gov/human-nutrition-and-food-safety/nutrient-lists-standard-reference-legacy-2018
[2] Brødsgaard, H. F. (1998). Oxalic acid in honey after formic acid and oxalic acid treatment for Varroa destructor. Apidologie, 29(3), 283-286.
Most kids are familiar with the sour taste of flower stems, which is caused by oxalic acid. Oxalic acid is a common organic acid found in many plants, serving as a natural defense mechanism against herbivores. It works in several ways:
- Sour Taste: Oxalic acid imparts a sour flavor to plants, deterring herbivores from consuming them. If you've ever tasted buttercup oxalis, rhubarb, or spinach, you've experienced the sourness caused by oxalic acid. The grittiness you feel on your tongue is due to the reaction between oxalic acid and calcium in your saliva, forming calcium oxalate crystals.
- Irritating Sap: Oxalic acid can make the sap of certain plants irritating to the mouth, skin, or eyes, further discouraging herbivory.
- Calcium Binding: Oxalic acid can bind to calcium in an animal's gut, potentially leading to calcium deficiency and even kidney stones if consumed excessively over an extended period.
- Oxalate Crystal Formation: Oxalic acid can form needle-like oxalate crystals, particularly in the leaves of some plants like Dieffenbachia (dumbcane). Ingesting these leaves can cause intense discomfort, swelling of the tongue, and temporary loss of speech, hence the plant's common name "dumbcane."
Due to its natural occurrence and relatively safe handling, oxalic acid gained traction as a potential mite control agent for honeybees:
- Natural Metabolism: Humans and animals have a natural metabolism to deal with oxalic acid as it is part of our diet.
- Environmental Safety: Oxalic acid is a naturally occurring compound, minimizing environmental impact.
- Non-Bioaccumulative: Oxalic acid is not lipid-soluble, meaning it won't accumulate in the wax of beehives.
- Honey Safety: Oxalic acid is a natural component of honey, and treatment with oxalic acid does not significantly increase its concentration in honey [2].
- Safe and Easy Application: Oxalic acid can be safely and easily applied to beehives using appropriate methods.
[1] USDA National Nutrient Data Laboratory (2015). Oxalic Acid in Foods. Retrieved from: https://www.nal.usda.gov/human-nutrition-and-food-safety/nutrient-lists-standard-reference-legacy-2018
[2] Brødsgaard, H. F. (1998). Oxalic acid in honey after formic acid and oxalic acid treatment for Varroa destructor. Apidologie, 29(3), 283-286.
HOW DOES ONE APPLY IT?
Vaporization is the best method.
Here is a summary of the articles from the Journal of Apicultural Research:
Effective Varroa Mite Control with Oxalic Acid Sublimation
The parasitic mite Varroa destructor has become increasingly difficult to control due to genetic resistance to synthetic acaricide chemicals. Oxalic acid (OA), a natural chemical, has emerged as a promising alternative for varroa mite control. A study conducted in southern England evaluated the efficacy of three OA application methods (trickling, spraying, and sublimation) in killing phoretic mites on adult worker bees under field conditions.
Key Findings:
Oxalic acid sublimation is a highly effective method for controlling Varroa destructor in broodless honey bee colonies during the winter months. It offers several advantages over other treatment methods, including:
Beekeepers should consider incorporating oxalic acid sublimation into their varroa mite control strategy, particularly during the winter when brood levels are low. This method provides a safe and effective way to control mite populations and protect the health of their colonies.
Additional Notes:
Effective Varroa Mite Control with Oxalic Acid Sublimation
The parasitic mite Varroa destructor has become increasingly difficult to control due to genetic resistance to synthetic acaricide chemicals. Oxalic acid (OA), a natural chemical, has emerged as a promising alternative for varroa mite control. A study conducted in southern England evaluated the efficacy of three OA application methods (trickling, spraying, and sublimation) in killing phoretic mites on adult worker bees under field conditions.
Key Findings:
- All three OA application methods demonstrated high varroa mortality (around 93–95%) when using 2.25 g OA per colony.
- Sublimation proved to be the superior method, achieving higher mortality at lower doses (0.56 or 1.125 g per colony).
- Sublimation using 2.25 g of OA resulted in significantly lower worker bee mortality in the 10 days following treatment compared to either trickling or spraying.
- Sublimation also resulted in lower colony mortality four months later in mid-spring.
- Colonies treated via sublimation had greater brood area four months later than colonies treated via trickling, spraying, or control colonies.
- A second trial confirmed the effectiveness of sublimation, with 97.6% varroa mortality and 87% of colonies surviving until spring.
Oxalic acid sublimation is a highly effective method for controlling Varroa destructor in broodless honey bee colonies during the winter months. It offers several advantages over other treatment methods, including:
- High varroa mortality at low doses
- Minimal harm to worker bees and brood
- No residue in hive
- Effective in broodless colonies
Beekeepers should consider incorporating oxalic acid sublimation into their varroa mite control strategy, particularly during the winter when brood levels are low. This method provides a safe and effective way to control mite populations and protect the health of their colonies.
Additional Notes:
- The use of oxalic acid for varroa mite control is not yet approved in all countries. Please check with your local authorities for regulations regarding the use of oxalic acid in your region.
- When handling oxalic acid, always wear appropriate protective gear, including gloves, goggles, and a respirator.
- Follow the manufacturer's instructions carefully when using oxalic acid sublimation products.