Marin Master Gardeners
University of California
Marin Master Gardeners

Encourage Pollinators

Andrenidae (Mining Bees) Photo credit: UC Berlelly Urban Bee Lab
Andrenidae (Mining Bees) Photo credit: UC Berlelly Urban Bee Lab
Want to help our ground nesting bees?  Here is information from Xerces Society.

What Do Ground Nesting Bees Need

Seventy percent of native bee species in the United States are ground nesting. There is not a lot known about the specific environments that ground nesting bees seek (compaction, soil type, etc.), but they do seem to be drawn to sunny, bare soil. Regardless of the details, we know that providing nesting sites is key to supporting these vital pollinators.

How to Start

If you’d like to support ground nesting bees in your yard, the first step is to clear vegetation from a sunny, well-drained area. If possible, select sites on an open, south-facing slope. Leave some clumps of grass or other low-growing plants to prevent erosion. Don’t turn the soil in the area, as bees need stable soil to nest in (young bees spend up to eleven months of the year underground).

Ground nesting bee
A wide variety of bees are ground-nesting—representing seventy percent of U.S. bee species. Pictured is an aptly-named mining bee (Andrena sp.). (Photo: Whitney Cranshaw, Colorado State University / Bugwood.org)

Careful With Pesticides

Another important step to support ground nesting bees is to protect them from pesticides. While some pesticide labels direct applicators to not spray a pesticide while bees are foraging, those instructions won’t protect ground nesting bees from exposures to contaminated soil. This contamination is especially bad news for species like the squash bee (Peponapis pruinosa) that nest at the base of crop plants.

There are a surprising number of “soil drench” products marketed for home gardeners to control insect and disease problems. Fortunately, a home gardener should have little to no reason to ever use pesticides. An ounce of prevention is often enough to avoid pest problems. And when a pest—whether it’s an insect, weed, or disease—is actually causing harm, it can be handled through non-chemical methods. You can learn more about managing pests in a home garden in our new guidance, Smarter Pest Management: Protecting Pollinators at Home.

squash bee
It is important to protect ground nesting bees from exposures to contaminated soil, which particularly impacts species like the squash bee (Peponapis pruinosa) that nest at the base of crop plants. As their name suggests, they are key pollinators of squash and gourds. (Photo: Barbara Driscoll)

Agriculture Problems

In agriculture, the common and growing practice of planting seeds coated with insecticides can also lead to contamination levels potentially harmful to bees nesting in and around crop fields. A number of concerns—insecticide-laden dust killing foraging bees, residues running into waterways, and pests building up resistance—have been raised about the practice of planting seeds coated with insecticides. Now evidence suggests that the soil contamination can also harm the many beneficial insects that live in the soil, including native bee species.

Xerces Society

Here at Xerces, we work with home gardeners, farmers, and other land managers to transform their pest management practices into methods that support biodiversity and make lands more resilient.

Read the complete article from the Xerces Society

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