Summer Varroa OA Timing: The August 15 Broodless Window
August 1–15 is the SERP-wide "no later" line for summer oxalic-acid vaporization. Miss the broodless window and OA efficacy drops from ~95% to under 50%. Here is the 2026 decision guide — the three-signal check, the 5-day protocol, and the two escape hatches when capped brood is still present.






















