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In the areas of the USA, where alfalfa seed is pollinated with leafcutter bees, often the bee keepers end up with only half of their initial bee population. In our climate, these bees double their population every year. We have sold these excess leafcutter bees into the USA for over 40 years. Over that same time we have learned an immense amount about the management of this bee. We share that information with both our bee customers, and the alfalfa seed/leafcutter bee growers who grow alfalfa seed for us.

Delivering Bees in Washington

Often we can make changes in our bee management to mitigate the issues we see. The key things we look at are percent of cells that contain a healthy bee larva, the percent that are parasitized, and the percent of cells that develop into female bees.

The USA alfalfa seed growers who source their leafcutter bees from us are buying:

  •  Our long term leafcutter bee management experience.

  •  The knowledge the bees they purchase were extensively tested.

  • The test results showing live count, percent parasites, percent females, and percent disease.

  • The test results they get are actually for the bees that are delivered.

  • The guarantee the bees were raised on our farm, and not blended with other bees.

  • Delivery at no extra cost into the USA Western states.

  • Pricing that guarantees the bees but follows market downturns.


For those of you not familiar with leafcutter bee production, here is some more information. The cycle starts with bee larva in cocoons that have been overwintered at about 5°C. These cocoons are placed in trays with screens, warmed up to about 29°C and the bee larva turns into a bee. This is timed so the bees emerge from the cocoons about the time the alfalfa begins to flower.  

The trays go out to the alfalfa seed fields, placed in little shelters, and the screens are removed. The bees leave the trays, mate, and begin looking for a little hole to begin reproduction. These little shelters contain nest boxes which are filled with the exact hole the bee needs to make its cocoons. The leafcutter bee makes a small capsule in the hole using leaf pieces. The bee fills the capsule with pollen and nectar, and in doing so it pollinates our alfalfa seed field. Next the bee lays an egg in the nectar, and closes off the capsule with more leaf pieces. The egg hatches, the larva eats the provisions, spins a cocoon around itself and goes dormant until the next year. This process is repeated over and over with a number of these capsules made in one tunnel. 

After about 6 weeks of making new bees, and pollinating the alfalfa seed crop, the old leafcutter bees all die. We are left with boxes containing tunnels filled with cocoons containing bee larva. These come into storage, the cocoons are extracted from the tunnels in the winter. Some of those cocoons are kept for our next years’ crops, and the excess are sold. They are primarily used to pollinate alfalfa seed, but are good pollinators of other crops, including hybrid canola and low bush blueberries.

Leafcutter Bees

The entire bee population is tested extensively in our own laboratory. We expect that over 90% of the cocoons should develop into a healthy leafcutter bee. All the leafcutter bee cocoons tested are cut open and carefully examined. If the cocoon contains other than a healthy larva, this is tabulated.

Without leafcutter bees, our alfalfa seed fields would be only hay fields. Alfalfa flowers have to be “tripped” to be pollinated to produce seed. The leafcutter bee is the only domesticated bee that will reliably pollinate alfalfa in our climate. We started with these bees in 1972, growing alfalfa seed and producing leafcutter bees. There was little information known or published at that time. The early leafcutter bee pioneers learned from each other, and by trial and error.

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