KentishBee · Kent, UK · Pests & Disease · Aug 17, 2026
Apiguard finished, recheck wash barely moved — 8 down to 6 per 300. What went wrong?
Pulled the second Apiguard tray last weekend after the full four weeks, waited a few days, then did my recheck wash yesterday. Pre-treatment I was at 8 per 300, now I'm at 6. That's nowhere near the knockdown I got last year.
Setup: two hives in Kent, supers were off, trays on the top bars with an eke over them, entrance not reduced. We had a properly cool grey fortnight in the middle of the treatment window though — barely got above 14C some days.
Only other thing I can think of is the smallholding two fields over. The chap there hasn't touched his three hives all year and one of them looks nearly dead, bees from somewhere are all over it. Could my girls be bringing mites home from robbing it out? Do I re-treat now with something else or wait for the broodless window?
#varroa#apiguard#thymol#reinvasion#alcohol-wash
▲ 10 votes💬 4 replies✅ Solved
4 replies
ImkerinLena · Aug 17, 2026 · ✅ Accepted answer
Two likely causes, possibly both. Thymol needs sustained warmth to evaporate — below about 15C daily highs the gel just sits there and efficacy drops sharply. Your cool fortnight cost you a lot. Second, yes: robbing a collapsing colony is the classic reinvasion route, mites ride your foragers home. Were the trays still half full when you pulled them? That confirms the temperature problem. Plan: monitor monthly, then oxalic in the broodless period in late autumn to catch what Apiguard missed. And talk to the neighbour — that dying hive is a mite bomb for everyone within 2 km.
muglabalci · Aug 17, 2026
I have seen exactly this with a neglected apiary near mine. You can treat perfectly and still take 20+ mites a week from a collapsing colony next door. The mites climb onto robbers on purpose, it is how varroa spreads between apiaries. Until that hive is dead and robbed out completely your counts will creep. ImkerinLena's oxalic plan is the right answer.
GeorgiaWes · Aug 17, 2026
Funny, down here in Georgia I have the opposite Apiguard problem — over 30C the gel flashes off in days and the bees beard outside instead of fanning it around. It really is a narrow temperature product. That's why I keep formic and oxalic in the rotation. Check what was left in your trays like ImkerinLena said, that tells the story.
KentishBee · Aug 18, 2026
Checked the bin — both second trays were easily half full of gel still. So temperature it is, probably with a side of reinvasion. I'll keep washing monthly and do oxalic once they're broodless. And I'll bite the bullet and knock on the neighbour's door. Thanks both.