Victoria AU winter: confirmed broodless this week — the one clean oxalic round of the year

Mid-winter here in Victoria and I did my July checks on a mild still day: quick look under the crown boards, hefted for stores, and pulled the centre frame on two of my six. Completely broodless, as expected for June-July down here. Which means it's the golden window. With no capped brood, every varroa in the hive is riding on adult bees where oxalic can actually reach them — nothing hiding under cappings. One clean vape round now does what three rounds five days apart do in the season, with a fraction of the disturbance. Did all six yesterday, in and out in under two minutes a hive, cluster barely stirred. For northern folks reading this in your honey flow: this is the same logic as your December-January window, just flipped. And if you make a broodless period artificially (queen caging, shook swarm), same rule applies. Sugar shake in spring will tell me how well it worked but the sticky boards this morning were satisfyingly grim.