MayaBees · Oregon, US · Pests & Disease · Aug 3, 2026

Alcohol wash came back around 5% — what actually works in a dearth, and is formic safe in this heat?

Washed all six of my hives yesterday here in Oregon and my two biggest ones came back at 14 and 16 per 300 — call it 5%. Way over threshold, I know I need to treat now, not in September. Problem is we're in a proper dearth and the forecast shows 33-34C afternoons for the next ten days. Formic Pro's label says don't apply over 29.5C for the first days, and I've heard the queen-loss horror stories. But oxalic won't touch the mites in the brood, and Apivar strips take 6+ weeks which feels like exactly the winter-bee window GeorgiaWes was posting about this morning. Supers are already off (dearth, nothing coming in anyway). Five deep colonies plus one nuc. What would you actually do — risk the formic, start Apivar today, or thymol? Fifth year and this is the highest count I've ever had in August.

#varroa#alcohol-wash#formic-pro#dearth#treatment

▲ 12 votes 💬 4 replies

4 replies

CorkBeeRon · Aug 3, 2026

With supers off, I'd start Apivar today and stop overthinking it. Yes it's 42+ days, but it starts killing phoretic mites immediately and it doesn't care what the thermometer says. Formic at 33-34C is how you end up posting a 'hive went queenless after Formic Pro' thread in two weeks. The 29.5C limit is not a suggestion.

ImkerinLena · Aug 3, 2026

I agree with CorkBeeRon on the main point: amitraz is the temperature-proof option and at 5% you need something working today. One alternative if you want faster knockdown — some run a single oxalic vape now to knock the phoretic load down, with strips in for the brood cycle. Belt and braces. But do not apply full formic doses in that forecast; brood kill and queen loss are very real above 30C.

GeorgiaWes · Aug 3, 2026

Georgia checking in — I've run Apiguard in 33C+ and it's doable but ugly: bearding, brood pulled out, and in a dearth the smell seems to make robbing worse. It works, but Apivar with your supers already off is the cleaner call. Treat all six at once including the nuc or you're just rotating mites around the yard.

MayaBees · Aug 4, 2026

Thanks all — strips went in this evening, all six colonies. Ordered enough for the nuc too. I'll wash again at the 3-week mark and report back. ImkerinLena, I might do the single oxalic vape this weekend for the knockdown, that logic makes sense to me.

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