What to Expect in May in Northeast WI

Here is what to expect in and around the hive in May.

In the hive

Egg laying and brood rearing are in high gear, with the brood area expanding rapidly. The bees are foraging for pollen and nectar to support this colony growth. They are likely to be less defensive than in fall, with less to protect and lots to do! With the growing population and possible overcrowding, mid-May is the beginning of swarm season. Queen cups are being built along the lower edges of brood frames. If the hive is crowded, some cups will likely be laid in. The drone population is growing. The Varroa mite population is also building.


  • Colony inspections should now take place every two weeks and include evaluating the brood pattern, confirming the presence of the queen and/or eggs, evaluating colony growth and available room, monitoring for pests and diseases, and other metrics. Record Keeping is key to making these inspections useful and actionable.
  • If you cannot inspect every one of your colonies, inspect those that are not showing as much activity on the outside.
  • If the bottom hive body is empty, you might consider moving it above brood nest.
  • If you install a package or nuc, allow two weeks for the colony to establish before you inspect it.


  • The bees should be foraging for what they need, but they also need a lot at this time, so remain vigilant and prepared to feed sugar syrup or a pollen supplement if necessary.
  • Provide supers if the brood chambers are full and the population/stores are growing with the first honey flows of spring.
  • Feed package bees or nucs upon their arrival.

Pests, parasites, and diseases

  • Monthly inspections should include monitoring for a range of pests and diseases: look for problems on the outside of the colony, in the brood, and on the adult bees themselves.
  • Monitor Varroa mite levels. At this point in the year, if you find two or more mites (per 100 bees) from a sugar shake, ether roll, or alcohol wash, you will want to treat. Treatment methods will depend on your management goals, the condition of the colony, and external conditions. Drone comb can be an effective cultural method at this time of year. This may be a good time to break the brood cycle (and therefore the Varroa reproduction cycle) by caging the queen or making splits.
  • Monitor for Nosema. It is present all year, but regular monitoring will still help you understand your normal levels and when/if they peak, particularly if you are seeking to understand why a colony is struggling.
  • Replace with fresh foundation or newly drawn comb two of your oldest frames in each hive body to reduce the accumulation of Nosema spores, American foulbrood spores, and pesticides.

Population management

  • Install any new packages or nucs that arrive.
  • Swarm control: if you do not want your bees to swarm, provide them with plenty of room and check that the colony is not honey bound (meaning that there is honey in or around the brood nest effectively restricting the access of the queen from other areas where she would lay eggs). Move the honey combs out of the brood nest and into a super if needed.
  • Keep an eye out for swarm cells. You may consider splitting the strongest colonies, particularly if you are looking to grow your operation or keep nucs in reserve. Cutting out swarm cells can prevent swarming as well, but needs to be done thoroughly and often (every few days).
  • You may be able to catch swarms this month.
  • Combine weak and strong colonies or equalize them if you want, but only after you have checked for diseases in the weak colony.
  • If your inspection reveals that a queen is under performing, if you want the vigor of a young queen, or if you want to introduce new stock for Varroa resistance or other properties, you might consider re-queening. This is a good month to do it, although local queens are probably in short supply this early in the year.
  • This is the best time (swarm season) to rear queens. To get from an egg to a mated and laying queen takes about one month takes about one month. Continue to build your cell builder colony while preventing it from swarming.
  • Check regularly for swarm cells, and cut out any you find.


  • Remove any remaining insulation, winter wraps, mouse guards, etc. Entrance reducers can be left on; many beekeepers use them year-round.
  • Consider adding a queen excluder to manage the honey supers more easily.
  • Set up bait hives if you want to catch a swarm.
  • Foundation will be more likely to be drawn out during a honey flow.

Hive products and services

  • Cut-outs tend to be easier this time of year, when populations are low.
  • You may be able to trap a small amount of pollen for later use or sale; this needs close monitoring to keep the pollen usable and frequent breaks to keep the bees adequately provisioned.

Yard maintenance

  • Mow the yard as necessary.

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