Varroa Mite Treatments Compared: Apivar, Formic, Oxalic and Thymol

The treatments side by side

US-registered varroa treatments, from their EPA labels (read October 20, 2026)

Product	Active ingredient	How long	Temperature	Honey supers on?
Apivar 2.0	Amitraz	At least 42 days; 70 days if brood is present (70 max)	No limit stated	No; supers can go on as soon as strips come out
Apivar (original)	Amitraz	42 days, up to 56	No limit stated	No; wait 14 days after removal
Apiguard	Thymol	Two trays, two weeks apart	Above 59 and below 105 °F (HBHC)	No
Formic Pro	Formic acid	2 strips for 14 days, or 1 strip for 10 days then another for 10	Daytime high 50 to 85 °F on application day	Yes
Mite Away Quick Strips	Formic acid	2 strips for 7 days, or 1 strip then a second 14 days later (21 days)	Daytime high 50 to 85 °F on application day	Yes
Api-Bioxal	Oxalic acid	One dribble or vapor application	Not stated; use when little or no brood	Yes
VarroxSan	Oxalic acid strips	42 to 56 days	Not stated on the label	Yes, with at least one box between strips and honey to be extracted
HopGuard 3	Hop beta acids	14 days, no later than 30	Above 55 and below 100 °F	Yes; strips in the brood chamber only

Two older strips, Apistan (tau-fluvalinate) and CheckMite+ (coumaphos), are still sold, but the HBHC guide lists them among the least effective options because mite resistance to both "is well documented." They also leave residues in wax. Skip them.

How well each one works

These are the effectiveness ranges the makers reported to the Honey Bee Health Coalition. They are best-case figures under label conditions, which is why a mite count after treatment matters more than any number in this table.

Product	Registrant-reported effectiveness (HBHC)	Main weakness
Apivar	Up to 95%	Slow knockdown; resistance where amitraz has been used for several seasons
Apiguard	74 to 95% (better when warm)	Temperature window; may slow the queen's laying
Formic Pro	83 to 97%	Heat: queen and brood losses above 92 °F
Mite Away Quick Strips	61 to 98%	Same heat risk as Formic Pro
Oxalic acid (Api-Bioxal)	82 to 99% with no brood present	Does not reach mites in capped brood
HopGuard 3	75 to 95%	Works only while the strips are wet; best with little sealed brood

Which to use, by season

Spring, before the supers go on

Apivar 2.0, Apiguard or a formic strip all fit here, but timing decides. Apivar 2.0 needs at least 42 days and 70 if there is brood, and the label says to remove all strips before the honey flow starts. If your flow is less than six weeks away, use a formic strip instead, because formic is the one chemistry the HBHC guide lists as "legally permitted when colonies are supered" in this phase.

Summer, supers on

This is formic acid's season, with one catch: heat. The Formic Pro label wants daytime highs between 50 and 85 °F on the day you apply it and warns that 92 °F during the first three days "may lead to excessive bee, brood and queen loss." The colony must be at least 10,000 bees covering about six deep frames, the bottom entrance must be fully open, and you should check that the colony is queenright a month later. In a hot spell, VarroxSan strips (permitted with supers on, kept one box away from honey you will extract) or HopGuard 3 (labelled up to 100 °F) are the alternatives.

Late summer and fall, after harvest

This is the treatment that decides whether the colony sees spring, because the colony is raising its winter bees. Once the honey is off, every option is open: Apivar 2.0, Apiguard while it is still above 59 °F, Formic Pro, or VarroxSan. The HBHC guide rates Apivar, the formic strips, the thymol products and HopGuard as highly effective in this phase. The seasonal calendar shows where this falls in your year.

Winter, or any broodless window

Oxalic acid kills mites riding on adult bees but not the ones sealed in brood, so it is a treatment for broodless colonies: midwinter in the North, a new package, a swarm, or a colony between queens. The Api-Bioxal label gives three methods:

• Dribble: dissolve 35 g in 1 liter of 1:1 sugar syrup and trickle 5 ml onto the bees in each occupied space between frames, up to 50 ml per colony.
• Vapor: 4.0 g per brood chamber in a vaporizer through a restricted bottom entrance, outdoor colonies only, upper entrances taped shut.
• Package spray: 3.0 mL of the 2.8% solution per 1,000 bees, after spraying them with plain syrup at least two hours earlier.

Note the vapor dose: the 2022 HBHC guide gives 1 g per hive box, and the current Api-Bioxal label (dated May 6, 2026) says 4.0 g per brood chamber. The label is the one to follow. Vapor is also the most hazardous method for the beekeeper; the label requires a respirator, chemical-resistant gloves and eye protection, and our protective gear guide covers what a bee suit does not.

Rotate the chemistry

Using one active ingredient over and over selects for mites that survive it, which is how Apistan and CheckMite+ lost their place. The HBHC guide recommends Apivar no more than twice a year and rotating with products that work a different way, and the HopGuard 3 label says to switch mode of action before returning to one you have used. A simple rotation is amitraz in spring, formic acid in summer, and oxalic acid in the broodless window, with a mite count after each.

Count before and after

Treat on a count, not on the calendar. An alcohol wash of about 300 bees from a brood frame gives a percentage; the HBHC treatment threshold is 2 to 3 percent in most of the season and 1 percent when the colony is dormant. Our varroa monitoring guide covers the wash cup and the thresholds by season, and the colony loss tracker shows how often beekeepers report varroa as a stressor. If the count after treatment has not dropped, suspect resistance or a label condition that was not met, and switch chemistry.

What to skip

• Homemade amitraz or oxalic mixes and products not labelled for honey bees in the US: the HBHC guide calls unregistered chemicals illegal.
• Powdered sugar dusting and mineral oil as treatments: the HBHC guide finds "little evidence" either affects mite populations.
• A screened bottom board or drone brood removal as your only control: both lower counts but are not treatments on their own.
• Feeding during a formic acid treatment: both formic labels say not to feed in the hive while the strips are in.