Varroa treatment options legal in Australia, and their withdrawal periods

Three years ago, the legal varroa treatment list in Australia fit on a sticky note: nothing, because we did not have varroa. Today the list is longer, but it changes often. APVMA registrations come and go. Emergency permits expire. New formulations get approved. This article is current as of early 2026; before you apply anything, check the APVMA Public Chemical Registration Information System for the live status. The label is law. This article is a guide.

A note on philosophy. The right approach to varroa is integrated pest management (IPM): monitor, intervene only when needed, rotate chemical classes to avoid resistance, use cultural methods (drone brood removal, brood breaks) where you can. The treatments below are the chemical leg of that strategy. None of them is a one-shot solution.

The categories

Varroa treatments fall into three groups by chemistry. Resistance builds within a group, not across groups. Rotating between groups is the foundational discipline.

• Organic acids: oxalic acid, formic acid. Naturally occurring in plants and honey at trace levels. No detectable residue in honey at correct dose. Generally low risk to bees, dose-dependent.
• Essential oils: thymol-based products (Apiguard). Slow acting, weather-dependent, food-grade.
• Synthetic pyrethroids: tau-fluvalinate (Apistan), flumethrin (Bayvarol). Fast acting, very effective when resistance has not built, but residues persist in wax. Resistance is a real concern with repeated use.

Oxalic acid

The work-horse of southern hemisphere varroa management. Two delivery methods, both with current Australian permits.

• Vaporisation (sublimation). A measured dose of oxalic acid crystals heated until it sublimes, leaving a fine powder coating the bees. Dose: typically 2 g per brood box. Equipment: a vaporiser tool ($80-200 AUD). Best applied during a broodless period, because the acid does not penetrate capped brood. Withdrawal: nil when applied without a honey super present. Always remove honey supers before treating.
• Dribble method. Oxalic acid dissolved in 1:1 sugar syrup, dribbled directly onto the bees between frames. 5 mL per seam of bees. Usable once per season; repeated dribbling damages the colony. Withdrawal: nil with no super present.

Best used in late autumn after the queen has slowed laying, when most of the mites are phoretic (riding on adult bees) rather than hidden in capped brood.

PPE: wear a respirator and goggles for vaporisation. Oxalic acid burns lungs.

Formic acid (Formic Pro / Mite Away Quick Strips)

The only varroacide that penetrates capped brood, which is what makes it valuable when you need to treat with brood present.

• Dose. Two strips per brood box for 14 days, or one strip per box for 21 days (Formic Pro labels both protocols).
• Temperature window. 10 to 29.5 degrees C daily ambient. Below 10, the acid will not vaporise enough to work. Above 29.5, it gases off too fast and you lose brood and sometimes the queen.
• Withdrawal. Nil; honey supers can stay on during treatment per the registered label, which makes Formic Pro the rare summer treatment that does not stop your harvest.
• Risk. Brood damage and occasional queen loss happen even within label conditions. Plan to inspect 7 days after treatment and again at 14 days.

The Australian climate is well suited to formic acid in spring and autumn. Summer treatments are risky in most regions because daytime temperatures push past the upper limit.

Thymol (Apiguard)

A gel containing thymol from thyme oil. Slow, reliable, and the easiest treatment to get wrong by impatience.

• Dose. One 50 g tray placed on top of the brood frames, replaced 14 days later with a second tray. Total treatment time: 4 to 6 weeks.
• Temperature window. 15 to 30 degrees C. Below 15, the thymol does not gas off enough to work.
• Withdrawal. Honey supers must be removed during treatment. Thymol residues taint honey. The recommended withdrawal post-treatment is around 2 weeks before re-supering for harvest.
• Side effect. Bees often dislike the smell and may temporarily move out of the upper box. This is not a failure of the treatment.

Apiguard is the most widely used non-acid treatment in Australia in 2026, partly because it does not need vaporiser equipment, partly because beekeepers find the application straightforward.

Synthetic pyrethroids: Bayvarol, Apistan

Plastic strips impregnated with flumethrin (Bayvarol) or tau-fluvalinate (Apistan). The strips hang between brood frames; bees brush past them and pick up a residue that kills mites on contact.

• Dose. Four strips per brood box for 6 weeks.
• Temperature window. Wide; works in cool weather where acids do not.
• Withdrawal. Honey supers must be removed during treatment. Residues persist in wax. Recommended rotation no more than once every two years to slow resistance.
• Risk. Resistance. New Zealand documented Apistan-resistant varroa within a decade of approval. Bayvarol has a slightly different mode but cross-resistance is reported. Use these strips as one element of a rotation, not as your default.

A sensible rotation, year by year

The point of rotation is to keep mites guessing and to avoid building any single treatment's resistance population. A workable two-year rotation for a southern Australian apiary:

• Year 1, autumn: Formic Pro, 14-day strip protocol. Confirms efficacy with a sugar shake one week after.
• Year 1, late winter (broodless): Oxalic acid vapour. Cleans up phoretic mites before brood ramps in spring.
• Year 2, autumn: Apiguard (thymol), 4-week protocol.
• Year 2, late winter (broodless): Oxalic acid vapour again.

Reserve the synthetic pyrethroids for years where you have a serious mite escalation and need a fast knockdown. Even then, single-season use, never two years in a row.

Honey contamination: the contamination paths that matter

The real risk to your honey is not residual chemistry from a treatment used correctly. It is:

• Treating with a super on when the label says "remove super first".
• Reusing wax that has been impregnated with synthetic pyrethroids.
• Stored, untreated honey in supers that picked up Apiguard fumes during a previous treatment.

The discipline is straightforward: respect the label, mark your treated boxes (a permanent marker dot on the inside of the lid), and rotate old wax out every 3 to 5 years.

Recording is now legally relevant

Every treatment goes on a record that includes:

• Date applied.
• Product and batch number.
• Dose.
• Hives treated.
• Withdrawal-until date.
• Date of post-treatment efficacy check (sugar shake or alcohol wash).

Under the Honey Bee Industry Biosecurity Code of Practice, you are expected to maintain treatment records and produce them on request. This is not a paperwork exercise. A withdrawal-until date that you cannot prove is a regulatory problem if your honey is ever sampled.

The treatment that works is the one you actually apply at the right time, at the right dose, on the right day, with the right honey super status, and the right record. The chemistry is the easy part.