Integrated Pest Management

Integrated pest management (IPM) does not ban medicines; it puts them on the last step of a sequence: first measure, check the threshold, prevent, try a non-chemical method, if necessary use an authorised medicine correctly, and measure the result again. The aim is not to eliminate the pest but to keep it below the damage threshold. This approach works on the same logic for varroa above all, but also for wax moth, hornets and brood diseases.

The basic idea

Treating by the calendar is easy but costly: unnecessary treatment breeds resistance, increases the risk of residues in honey and wax, and often hides the true scale of the problem. In IPM every decision is based on a measurement, and the result of every treatment is measured again.

Trying to wipe out the pest completely is both impossible and leads to overuse of medicines. The goal is to maintain a level at which the colony stays healthy.

Six steps

1. Monitoring

A decision made without knowing how much of a pest there is, is a guess. For varroa this step includes counting by a wash method several times a year and, at every inspection, checking the brood pattern, the hive entrance and the floor board. Write down the results together with the hive number.

2. Threshold

Not every sighting of a pest calls for intervention; intervention is made when a predetermined threshold is exceeded. For varroa the commonly used threshold is 2–3 mites per hundred bees in the summer months; lower values are aimed for in spring and while winter bees are being raised. Thresholds vary by region; base your decisions on the recommendations of your beekeepers' association or the official veterinary service / local agriculture authority.

For notifiable diseases (American and European foulbrood, small hive beetle, Tropilaelaps) there is no threshold: they are reported as soon as they are suspected.

3. Prevention

Reducing a problem before it arises is the cheapest way:

• Strong, well-fed colonies: Sufficient honey and pollen, a young, productive queen.
• Genetics: Choosing queens from lines with strong hygienic behaviour that are adapted to local conditions.
• Comb renewal: Replacing part of the old, darkened combs every year; this reduces the build-up of disease agents and residues.
• Hygiene: Cleaning hive tools and gloves between colonies; not buying comb and equipment from unknown sources.
• Quarantine: Keeping a newly bought colony or a caught swarm separate for a while and checking it.
• Preventing robbing: Not leaving honey and syrup in the open, reducing the entrance of weak colonies.
• Correct comb storage: Storing empty combs in a cool, light, airy place and checking them regularly for wax moth.

4. Non-chemical intervention

When the threshold is exceeded, the first option is often not a medicine:

• Drone brood removal: Capped drone brood, which the mites prefer, is cut out and discarded.
• Brood break: The colony is left temporarily broodless by caging the queen or using a trap comb.
• Splits and artificial swarms: These provide both swarm prevention and mite reduction.
• Mechanical measures: Against hornets, reducing the entrance and trapping; against wax moth, sorting combs and keeping them in the cold.

5. Chemical intervention

If necessary a medicine is used, but under these rules:

• Only products authorised in your country; the dose, duration and method on the label.
• Rotating active substances by mode of action. Organic acids (oxalic, formic) and thymol are a solid pillar of the programme, as their risk of resistance is low.
• Following the rules on honey harvest and honey supers; carrying out treatments with a residue risk after the harvest.
• Not using unauthorised mixtures or home-made treatments.
• Not using antibiotics in bees: they suppress the symptoms, do not eliminate the agent and leave residues in honey.

6. Evaluation: the most often skipped step

IPM does not end with the medicine. Once the treatment period is over, measure again with the same method. The difference between the counts before and after treatment is the real efficacy of the method in your apiary. If the expected drop is not there, investigate the possibilities of dose, timing, reinfestation and resistance.

IPM summary for the main pests

Why is it worth the effort?

• The development of resistance slows down; the available products keep working for longer.
• The risk of residues in honey and wax is reduced; the market value of your products is protected.
• Costs fall, because no unnecessary treatments are carried out.
• Colony losses fall, because problems are spotted early.

Topics in this section

Under this heading, varroa monitoring methods and thresholds, acaricide resistance, brood break techniques and the procedure for notifiable diseases are described in detail on separate pages.