When it comes to bees on farmland, the more the better, according to a bee expert.

During a recent online seminar, Andony Melathopoulos, assistant professor and pollinator health extension specialist at Oregon State University, taught farmers how to make their land more hospitable to bees.

Melathopoulos covered how to recognize bees, create a plant inventory and manage weeds in a bee-friendly way.

Recognizing species

North America has about 3,510 bee species, and OSU researchers have identified an estimated 782 bee species in the state.

Fewer than 10% of bee species are social; most are solitary.

Certain bee species nest in the ground, said Melathopoulos. Some dig burrows, while others — including some bumble bees — nest in existing holes such as rodent burrows. Melathopoulos said leaving a strip of land untilled can encourage ground-nesting bees to settle.

Bumble bees can help increase the fruit set on tomatoes, eggplants and other crops honey bees avoid.

About 30% of species, including mason bees, are cavity nesters, meaning they nest in hollow stems and similar cavities. Farmers can encourage mason bees to stay on the farm by installing tubes 9 inches long with 5/16-inch diameter holes, cleaning cocoons in the fall and protecting them in the winter.

Mason bees, he said, pollinate many fruits, including cider apples and berries.

Strategies

Some bees are polylectic, collecting pollen from many unrelated flowers. Others are oligolectic, preferring a narrower spectrum of pollen sources. Yet others are monolectic, meaning they forage on a single plant species or a few closely related species.

OSU and the Natural Resources Conservation Service have lists of plants that can support bees throughout different regions.

Melathopoulos quoted a Canadian ecologist, Mark Wonneck: “Protect what you have. Add what you can.” In other words, if you already have plants that support bees, nurture them. If you can add more plants, do it.

Melathopoulos said farmers can be strategic in achieving conservation or pollination goals.

For example, he talked about Kim Patten, a retired Washington State University researcher who wanted bumble bees to pollinate cranberries. Patten planted heather to support the bumble bees in spring and timed it so the heather would fall out of bloom just as cranberries came into bloom, providing bees with a continuous source of food without allowing the heather to outcompete the cranberries.

Plant inventory

Melathopoulos said Oregon has a program to help farmers document which bee-friendly plants they have.

First, he said, a farmer should download the iNaturalist software application. Whenever they see a plant on their land, they should take a photo and upload it to the app, which will use an algorithm to identify the plant.

Second, the farmer should map their property’s boundaries using Google Earth, export the map as a “KML” file and upload it to iNaturalist.

Third, the farmer should create an iNaturalist project combining the map with the plant data. Over time, as the farmer takes plant photos, the app will populate the map.

Fourth, the farmer should export the project from iNaturalist and email it to Melathopoulos, who will overlay the farmer’s map with Oregon Bee Atlas data that will help him predict the bee species on the farm. He will then send the farmer a customized chart showing which bee-friendly plants to nurture and which other plants the farmer could add.

Weed management

Melathopoulos recommended that in areas of dense native bee-friendly plantings, farmers should spot-spray, mow or use targeted herbicides that mainly kill grasses instead of flowers.

Recommended resources from Melathopoulos:

• Bee Steward Program
• Book: Weed Control in Natural Areas in the Western United States
• List: Shrubs and trees that support bees
• NRCS: How to choose a good pollinator seed mix
• E-mail newsletter: Bee Notes

How to contact Andony Melathopoulos: 

Andony.Melathopoulos@oregonstate.edu 

541-452-3038

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