How should bees be treated for mites in spring? - briefly
Apply a brood‑free miticide such as oxalic acid vaporization early in the season, adhering to label rates. Rotate with a different chemistry (e.g., formic acid) to mitigate resistance.
How should bees be treated for mites in spring? - in detail
Effective spring mite control for honey bees requires precise monitoring, timely intervention, and integrated tactics.
Begin with colony assessment. Inspect each hive at the first sign of brood emergence. Collect a sample of about 300 adult bees, place them in a jar with 95 % alcohol, shake for 30 seconds, and count the mites on a white surface. A count of 3 or more mites per 100 bees generally signals the need for treatment.
Choose a control method that matches the infestation level and colony condition.
- Organic acids – Oxalic acid vaporized or sugar‑sprayed in early spring (when brood is minimal) kills phoretic mites without harming brood. Apply 1 g oxalic acid per hive, repeat after 7 days.
- Formic acid – Effective against mites inside capped brood. Use a commercial pad or gel, maintaining hive temperature between 15–27 °C for 8–12 hours. Rotate pads to avoid queen exposure.
- Essential oils – Thymol or menthol strips placed on frames for 4 weeks, with temperature kept above 20 °C. Replace strips every 7 days.
- Synthetic miticides – Amitraz or fluvalinate may be used if resistance testing shows susceptibility. Apply according to label rates, limit to two consecutive years to delay resistance.
Complement chemical measures with cultural practices.
- Drone brood removal – Insert a drone comb, allow mites to concentrate, then freeze and discard the comb.
- Brood interruption – Create a short broodless period by removing all frames with sealed brood, then re‑introduce after 10 days; mites cannot reproduce without brood.
- Hygienic stock – Replace queens with lines selected for Varroa‑sensitive hygiene, reducing mite reproduction.
After treatment, re‑evaluate mite levels using the same sampling method. If counts remain above threshold, repeat the chosen method after a 7‑day interval, ensuring not to exceed the maximum number of applications stipulated by product regulations.
Maintain hive hygiene: clean entrance reducers, replace old frames, and store unused equipment in a mite‑free environment. Record all treatments, dates, and mite counts to track efficacy and adjust future strategies.
Following this systematic approach minimizes mite populations while preserving colony health throughout the spring season.