Practical Guide: 1.4. Overview of methods for establishing young colonies

The creation of nucleus colonies, alongside drone brood removal, is a central biotechnical measure to slow the development of varroa. Practical Guide 1.4 compares the methods described by the Swiss Bee Health Service (1.4.2–1.4.7) and supports decision-making. The basis is the official Practical Guide 1.4 “Overview of Methods for Nucleus Colony Formation” (V 2511).

Official Practical Guide (BGD / SSA) – Summary

Practical Guide: 1.4 Overview of Methods for Nucleus Colony Formation (V 2511)

• Objective: Comparison of the methods for nucleus colony formation described by the BGD (Practical Guides 1.4.2–1.4.7) and facilitation of decision-making.
• Basis regarding varroa development: “In spring, up to 80% of the mites are in the brood and only a few on the bees.” Nucleus colonies without brood (swarm-like procedures) start with a lower mite load.
• Slowing mite development through brood breaks:
  • “In the absence of bee brood, mite reproduction is interrupted.”
  • “During a brood break of 25 days, studies have demonstrated a varroa reduction of about 40–50%.”
  • After egg-laying resumes, reproduction is slowed for at least three brood cycles.
  • Possibility of oxalic acid treatment.
• Varroa treatment in nucleus colonies: “In every broodless phase there is the possibility of oxalic acid treatment (Practical Guide 1.3.1).” If the nucleus colony is treated at creation, the first summer treatment is optional; further steps according to the varroa treatment concept.
• Definitions:
  • Parent colony: Production colony from which bee mass (with or without brood) and, depending on the method, the old queen are removed for nucleus colony formation.
  • Nucleus colony: Unit composed of parts of one or more parent colonies, with or without brood combs.
• Decision factors: The practical guide compares the methods with regard to their influence on varroa development (brood break, no brood from the parent colony, overall slowing effect) as well as additional aspects such as comb building, emergency queen rearing, level of difficulty, influence on honey harvest, risk of transmission of brood diseases, and timing of the measure.

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Summary based on Practical Guide 1.4 (V 2511). Last review: 01/2026.

Learn more:

• Understanding swarming behaviour
• Grafting for sanitary purposes (brood removal)
• Dividing colonies
• Practical Guide 1.1: Varroa Concept
• Renewing colonies and queens