The four layers

IPM for varroa is usually described as four layers that work together: monitoring, cultural methods, genetics and treatment. The more of the first three you build in, the less the last one has to do.

1. Monitoring, the layer everything rests on

You cannot manage what you do not measure. A wash of about 300 bees every 30 days from spring through fall gives you the number that tells you when to act and whether your other layers are working. Without it, every other tactic is guesswork. This is the cheapest and most important habit in the whole plan, and the mite count calculator does the math for you.

2. Cultural methods that use the mite against itself

A few management tricks knock mites back without a single treatment.

  • Brood breaks. When a colony has no open brood, mites have nowhere to breed and sit exposed on adult bees. A split, a swarm or caging the queen for a couple of weeks all create one. Time an oxalic treatment to the break and it lands several times harder than it would with brood present.
  • Drone brood trapping. Varroa strongly prefer drone brood. Put a frame of drone comb in the nest, let the bees fill and cap it, then pull and freeze it before the drones emerge. You take a batch of mites out with the comb. Miss the timing and you have raised mites instead, so this one lives or dies by the calendar.
  • Screened bottom boards. A small help at best. Mites that fall through cannot climb back, but on its own a screened board barely moves the count. Treat it as a minor assist, not a control.

3. Genetics, the long game

Some bees fight mites for you. Stock selected for Varroa Sensitive Hygiene, or VSH, detects mite-infested pupae and pulls them out of the cells, which interrupts the mite's reproduction before it finishes. Colonies with strong hygienic behavior carry lower mite loads for the same treatment effort. You do not need a breeding program to benefit. Buying locally raised, survivor-stock queens moves your yard in this direction one requeening at a time.

4. Treatment, applied with precision

The chemical layer is still here, it just does less and lands better. When your count crosses threshold, you reach for the treatment that fits the season and the weather, which is the whole point of the which treatment guide. Because your cultural and genetic layers have taken pressure off, you treat fewer times and with better timing, which also slows resistance to the products you rely on.

Putting it together

A worked example. You run local survivor-stock queens. You wash every colony monthly. You make spring splits, which give you increase and a brood break in one move. You slip a drone frame into your strongest hives and pull it on schedule. When the late July count still crosses threshold, and it often will, you treat, but you treat strong colonies with the right product for the weather, and you confirm the result with a follow-up wash. No single layer carries the yard. Together they keep the mites under the line with less chemical than treating blind ever would.

Sources and further reading

Track your counts, splits, drone frames and treatments in your hive records. IPM is a season-long pattern, and the pattern is only visible if you write it down.