Oxalic Acid Dihydrate

For Varroa mite control on bees

Active Ingredient:

 Oxalic Acid Dihydrate: ............................................................97.0%

Inert Ingredients: .........................................................................3.0%

TOTAL:....................................................................................100.0%

PRECAUTIONARY STATEMENTS

HAZARDS TO HUMANS AND 

DOMESTIC ANIMALS

DANGER

Acute Hazards: May be fatal if swallowed. 

Harmful if inhaled. Corrosive. Causes irreversible 

eye damage. 

Hazard avoidance: Do not breathe dust or fumes. 

Do not get in eyes, on skin, or on clothing. Wear 

protective clothing, eyewear, and respiratory 

protection as listed under “Personal Protective 

Equipment.” Wash thoroughly with soap and water 

after handling and before eating, drinking, 

chewing gum, using tobacco or using the toilet. 

Remove and wash contaminated clothing before 

reuse. 

PERSONAL PROTECTIVE EQUIPMENT:

Handlers and Applicators who apply product 

by the Solution Method must wear:

- Long-sleeved shirt and long pants

- Socks and shoes

- Protective gloves 

- Protective eyewear such as goggles

- Half-face respirator with cartridge and/or 

particulate filter

Handlers and Applicators who apply product 

by the Vaporizer Method must wear:

- Long-sleeved shirt and long pants 

- Socks and shoes

- Waterproof gloves 

- Protective eyewear such as goggles

- Half-face respirator with cartridge and/or 

particulate filter

User Safety Requirements:

Follow manufacturer’s instructions for cleaning/ 

maintaining PPE. If no such instructions are 

provided for washables, use detergent and hot 

water. Keep and wash PPE separately from other 

laundry.

Wash hands before eating, drinking, chewing 

gum, using tobacco, or using the toilet. 

Remove clothing/PPE immediately if pesticide 

gets inside. Then wash thoroughly and put on 

clean clothing.

Remove PPE immediately after handling this 

product. As soon as possible, wash thoroughly 

and change into clean clothing.

DIRECTIONS FOR USE

It is a violation of Federal law to use this 

product in a manner inconsistent with its 

labeling.

READ THIS LABEL: Read the entire label. 

This product must be used strictly in 

accordance with this label’s precautionary 

statements and use directions, as well as 

with all applicable State and Federal laws 

and regulations.

USE RESTRICTIONS:

Oxalic Acid Dihydrate applications are for 

outdoor use only.

DO NOT use in enclosed overwintering 

areas.

Use only in late fall or early spring when little 

or no brood is present. Oxalic Acid Dihydrate 

might damage bee brood. Oxalic Acid 

Dihydrate will not control Varroa mites in 

capped brood. 

Do not use when honey supers are in place 

to prevent contamination of marketable 

honey. 

Apply only when monitoring indicates 

treatment is required. Consult state

guidelines and local extension experts for 

monitoring protocols and thresholds for 

treatment.

(See next page for additional DIRECTIONS 

FOR USE)

FIRST AID

If swallowed -Call a poison control center or doctor immediately for treatment advice.

-Have person sip a glass of water if able to swallow.

-DO NOT INDUCE VOMITING unless told to by the poison control 

center or doctor.

-Do not give anything to an unconscious person.

If on skin or -Take off contaminated clothing.

clothing -Rinse skin immediately with plenty of water for 15-20 minutes.

- Call a poison control center or doctor for advice.

If inhaled -Move person to fresh air.

-If person is not breathing, call 911 or an ambulance, then give artificial 

respiration, if possible. DO NOT use mouth-to-mouth method if victim 

ingested or inhaled the substance, use respiratory medical device.

-Call a poison control center or doctor for advice.

If in eyes -Hold eye open and rinse slowly and gently with water for 15-20 

minutes. Remove contact lenses, if present, after the first 5 minutes, 

then continue rinsing eye.

-Call a poison control center or doctor for advice.

Have the product container or label with you when calling a poison control center, 

doctor, or going for treatment. 

For non-emergency information concerning this product, call the National 

Pesticides Information Center (NPIC) at 1-800-858-7378 seven days a week, 6:30 

am to 4:30 pm Pacific Time (NPIC Website: www.npic.orst.edu).

NOTE TO PHYSICIAN: Probable mucosal damage may contraindicate the use of 

gastric lavage. Provide general supportive measures and treat symptomatically. 

Treatment should be rapidly instituted by giving a dilute solution of calcium lactate, 

limewater, finely pulverized chalk, plaster, and/or milk to supply large amounts of 

calcium to inactivate oxalate by forming an insoluble calcium salt in the stomach. 

Gastric lavage is controversial, since this may compound an already severe 

corrosive lesion in the esophagus or stomach. However, if used, gastric lavage 

should be done with limewater (calcium hydroxide). Intravenous gluconate or 

calcium chloride solutions should be given to prevent hypocalcemic tetany; in 

severe cases parathyroid extract also has been given. Additionally, acute renal 

failure should be anticipated, and careful fluid management is necessary. 

Metabolically its toxicity is believed to be due to the capacity of oxalic acid to 

immobilize calcium and thus upset the calcium-potassium ratio in critical tissues. 

Effective therapy against burns from oxalic acid involves replacement of calcium.

UNITED STATES DEPARTMENT OF 

AGRICULTURE

AGRICULTURAL RESEARCH SERVICE, Bee 

Research Laboratory

10300 Baltimore Avenue, Bldg. 306, Rm. 315 

BARC-EAST

Beltsville, MD 20705

EPA Reg. No. 91266-R

EPA Est. No. xxxxx-xx

Net Contents: ______

Batch Code No.: _____________

EPA Reg. No. 91266-xx

page 1 of 2

KEEP OUT OF REACH OF CHILDREN

DANGER-PELIGRO
EPA Reg. No. 91266-xx

page 2 of 2

DIRECTIONS FOR USE, continued

APPLICATION DIRECTIONS: 

Oxalic acid is used to treat broodless colonies, packages, or swarms. This product can also be used as a “clean up” Varroa 

treatment 30 days following a formic acid application where Varroa infestations are problematic.

SOLUTION METHOD:

NOTE: To completely dissolve Oxalic Acid Dihydrate, use warm syrup. 

Dissolve 35 g of Oxalic Acid Dihydrate in 1 liter of 1:1 sugar: water (weight:volume). Smoke bees down from the top bars. 

With a syringe or an applicator, trickle 5 ml of this solution directly onto the bees in each occupied bee space in each brood 

box. The maximum dose is 50 ml per colony whether bees are in nucs, single, or multiple brood chambers. Under certain 

unfavorable conditions (e.g., weak colonies, unfavorable overwintering conditions), this application methods may cause 

some bee mortality or overwintering bee loss.

VAPORIZER METHOD:

Apply only to outdoor colonies with a restricted lower hive entrance. Seal all upper hive entrances and cracks with tape to 

avoid escape of Oxalic Acid vapor. Smoke bees up from the bottom board, Place 2.0 g Oxalic Acid Dihydrate powder into 

vaporizer. Follow the vaporizer manufacturer’s directions for use. Insert the vaporizer apparatus through the bottom 

entrance. Apply heat until all Oxalic Acid has sublimated. 

SPRAYING PACKAGE BEES

Ensure bees are clustered before applying oxalic acid (for example store in cool dark location 24 hours before application).

Spray broodless package bees with a 1:1 sugar:water solution at least 2 hours before spraying with oxalic acid. This allows 

bees to fill honey stomachs with sugar water reducing ingestion of oxalic acid.

Mix a 2.8% oxalic acid solution by dissolving 35 g of Oxalic Acid Dihydrate in 1 liter of 1:1 sugar: water (weight:volume). 

Evenly apply 3.0 mL of 2.8% oxalic acid solution per 1,000 bees using a pump sprayer or battery powered sprayer (for 

example, a typical 2 lb package contains approximately 7,000 bees which requires 21 mL of solution). Apply solution evenly 

on both sides of the package. 

Store bees in a cool darkened room for 72 hours before hiving.

POST TREATMENT CLEANUP: All clean up and maintenance activities should be performed in a well-ventilated 

area, preferably outdoors. 

RESISTANCE MANAGEMENT: Any Varroa mite population has the potential to become resistant to insecticides. 

Resistance development is affected by both the frequency of application and rate/dose of application. Continued reliance 

on a single class of miticide or single miticide with the same mode of action will select for resistant individuals which may 

dominate the mite population in subsequent generations. In order to prevent resistance development and to maintain the 

usefulness of individual insecticides it is important to adopt appropriate resistant management strategies. 

To delay resistance:

• When possible, rotate the use of miticides to reduce selection pressure as compared to repeatedly using the 

same product, mode or action or chemical class. If multiple applications are required, use a different mode of 

action each time before returning to a previously-used one.

• Base miticide use on Integrated Pest Management (IPM). This includes proper pest identification, monitoring for 

locality specific economic threshold and economic injury levels, record keeping, and utilizing all available control 

practices (cultural, biological and chemical).

• Maximize efficacy by following all label instructions including dosage and timing of application.

STORAGE AND DISPOSAL

Do not contaminate water, food, or feed by storage 

or disposal.

PESTICIDE STORAGE: Store only in original 

container, in a dry place inaccessible to children, 

pets, and domestic animals.

PESTICIDE DISPOSAL: Wastes resulting from the 

use of this product may be disposed of on site or at 

an approved waste disposal facility.

CONTAINER HANDLING: Nonrefillable container. 

Do not reuse or refill this container.

PLASTIC CONTAINER DISPOSAL: Triple rinse 

container (or equivalent) promptly after use. Offer 

for recycling, if available. Otherwise, puncture and 

dispose of in a sanitary landfill, or, if allowed by 

state and local authorities, by burning. If burned, 

stay out of smoke.