Garden Tip #430

The pollinators need our help. Not just because humanity’s food supply relies on pollinators, but because invertebrates are the backbone of a healthy ecosystem. Concerned gardeners will find guidance and an action plan in The Pollinator victory garden: win the war on pollinator decline with ecological gardening: how to attract and support bees, beetles, butterflies, bats, and other pollinators by Kim Eierman (2020).

Eierman’s Tips for a Pollinator Victory Garden

Don’t use pesticides of any kind, including organic; and avoid buying nursery plants treated with “neonics.” A quality nursery should be able to tell you whether their plants have been treated with this systemic pesticide.
Create over-wintering habitat by leaving some fallen leaf litter on the ground. Soil organisms will also appreciate the leaf litter.
Create growing season habitat for solitary, ground-nesting native bees by leaving a sunny, sandy patch of soil free of mulch. Then watch out for little mounds with a hole in the center, kind of like a tiny volcano, for evidence of a bee making a nest for her larvae.
Native pollinators prefer native plants, and some rely exclusively on native plants. Eierman compiled a list of plants for the Pacific Northwest on her website, Ecobeneficial.com.

Eierman makes the case for pollinators

Grass-carrying wasps

Who has moved into the tubes in my mason bee house? There are these strange bundles that seem to have dead crickets entombed in them. Do I need to remove them?

Your description and photos convince me that these bundles were made by grass-carrying wasps (Isodontia species) who store food (such as crickets!) with their cocoons to nourish the larvae when they emerge. Your mason bee house was a convenient location to nest. They look for any hollow cavities (such as stems, trees, or even window tracks), and the mason bee tubes were a perfect spot.

They would have built the nest in early summer, emerging later (late July through September) to visit flowers for pollen and nectar.

Grass-carrying wasps are beneficial insects just like mason bees, and serve as pollinators, too. This article from Heather Holm’s Restoring the Landscape with Native Plants (author of Bees: An Identification and Native Plant Forage Guide, 2017) mentions them visiting Solidago, Eupatorium, and Plantago.

As far as removing the grass-shrouded crickets or katydids, I would follow your normal mason bee housecleaning schedule. Usually, cleaning the tubes would be done between October and December. This page from David Suzuki’s web page describes the process.

If you are curious to see a grass-carrying wasp in action, entomologist Michael Raupp’s Bug of the Week page includes a video of a wasp creating its nest.

Beneficial insects, Grass-carrying wasps, Honeybees and pollinators

Washington Bumble Bees in Home Yards and Gardens

“To better conserve and protect bumble bees in home landscapes in the Pacific Northwest, this publication aims to develop public awareness and appreciation of bumble bees and their role in pollination. It will also help readers recognize bumble bees, understand their general life cycle, and suggest things homeowners and the general public can do to encourage these fascinating and beneficial insects.”

Bee Basics: An Introduction to Our Native Bees

A 48 page booklet by By Beatriz Moisset, and
Stephen Buchmann. Published by the USDA Forest Service and Pollinator Partnership Publication. Topics include biology, species guide, life cycles, foraging habits, and conservation.

bumble bee nest removal

I am taking a large, overgrown fern out of our backyard, to make room for more lawn (we are doing the opposite in other parts of our outdoor space). While I was cutting off the fronds, to get to the root, bees started to hang out near the cuttings. There seems to be a bumblebee nest at the base of our fern. I know that honeybees have been dying. Should I leave the bees’ nest? They are not aggressive, but I would like to take out the plant. Is there some way to move the nest?

Bumblebees are bees native to North America, and they are above all important
pollinators, so if you can leave them, that would be ideal. Fortunately, bumble
bees nest for only one year, so if you don’t mind waiting until fall to remove
your plant that might be the best solution for you and them. This
information, and more, is in Garden Insects of North America, by Whitney Cranshaw
(Princeton: Princeton University Press, 2004). Like honeybees, bumblebees are currently experiencing
a decline, so it’s a good time to protect them. The Xerces Society has useful information on this and other bee-related topics.

Bees choose their nests in the spring, when a queen bumblebee comes out from hibernation. They often choose an old rodent or bird’s nest, or something else with lots
of good insulation, and establish a colony. Find more about the life cycle of bumblebees here. In fact, you can encourage bumblebees to nest in spring by building them a
nesting site! The Xerces Society describes nest plans, if you would like to encourage bumblebees elsewhere.

If you do decide you need to move the plant before fall, you might be able to
get information on moving the next by contacting the Puget Sound Beekeepers
Association or a Seattle-area stinging-insect enthusiast, Jerry the Bee Guy. Another local stinging insect removal expert is Dan the Bee Man.

Ladybugs: benefits and drawbacks

Ladybugs: are they beneficial? Invasive? I know that nurseries sell them for release into the garden. Is that a good idea?

The type of ladybug most often for sale is an introduced species. This factsheet from Linda Chalker-Scott of Washington State University provides a thorough explanation of why it is problematic.

Multicolored Asian lady beetles are generalist predators and they can be beneficial in the garden, but they also displace the North American native species of lady beetle. Purchasing them is not recommended and is probably a waste of money because, well, they have wings, and they will fly away. Former University of Washington Botanic Gardens director Sarah Reichard’s book, The Conscientious Gardener, advises that you instead avoid using insecticides so that your landscape will naturally attract beneficial insects, particularly native ones.

Another drawback of releasing ladybug larvae in your garden is that they sometimes find their way indoors, where you don’t want them to be. The multicolored Asian lady beetles (Harmonia axyridis) look for crevices to spend the winter hibernating and they seem particularly fond of light colored south walls. If you don’t want to find thousands of these beneficial insects flying around your house on the first sunny day in spring, fill the cracks in your house siding with caulk. For a description, management ideas, and detailed vacuum cleaner bagging instructions, Ohio State University Extension has a fact sheet on these insects. Inside a home, the insect droppings are a human health hazard, and can trigger asthma and other allergic reactions.

controlling woolly aphids on apple trees

Is there something I can do to prevent my apple trees from getting woolly aphids? I’d rather not have to spray anything.

Encouraging beneficial insects is one step you can take. A 2013 study at Washington State University found that planting Alyssum flowers attracted syrphids which did a good job of reducing woolly aphid populations. Here are highlights of the paper that was published based on the study’s findings:

Sweet alyssum flowers had the highest attractiveness to syrphids.
Faster suppression of woolly apple aphid occurred on trees closer to alyssum flowers.
Higher densities of natural enemies were observed near sweet alyssum plantings.
Natural enemies were found to move between sweet alyssum and adjacent apple trees.

As Washington State University’s HortSense website (search under “tree fruit,” “apple,” then “aphids”) indicates, encouraging beneficial insects is a good practice for the control of all 3 main types of aphids affecting apples, be they woolly, rosy, or green:

Control honeydew-feeding ants, which may protect aphid colonies from predators.
Encourage natural predators including ladybird beetles, lacewings, syrphid (hover) fly larvae, and parasitic wasps. Avoid use of broad-spectrum insecticides which kill these beneficial insects.
Hand-wipe or prune to control small, localized infestations (when practical).
Provide proper nutrition. High levels of nitrogen encourage aphid reproduction. Switch to a slow-release or low-nitrogen fertilizer.
Wash aphids from tree with a strong stream of water before leaves curl.

Our Native Bees

[Our Native Bees] cover

Paige Embry is an engaging and humorous writer exploring the topic of bees. And not just any bees. She is passionate about “Our Native Bees”, which is also the title of her new book. She gives honey bees their due, but laments they “get all the press – the books, the movie deals – and they aren’t even from around here.”

While I haven’t seen many movies on honey bees, the author makes her point. We have native bees that are far better pollinators, do equal work with fewer numbers, fly in nastier weather, and often use better technique. An example of the latter is buzz pollination, or shaking the pollen from the flower. Honey bees haven’t learned this trick, but bumble bees and others have and their work facilitates some of our favorite foods, including tomatoes.

This is not a field guide. While the author lives in Seattle, her scope for natives includes most of North America. There are some excellent, close-up photographs, but their purpose is to supplement the text, not help with ID. Instead, this is an investigative study of many apian topics and to recognize that bees are diverse and have the power to fascinate people, even when we mislabel or misunderstand them.

One of the author’s major themes is agriculture. For example, she studies the production of lowbush blueberries in Maine and neighboring New Brunswick, an interwoven history of wild plants, wild bees, managed plants, managed bees, and the impact of various attempts at pest management. Recounting this could be deadly dull, but in Emery’s hands, it is most engaging.

Throughout all the stories, there are questions asking what is possible. Can native bees provide better solutions for our pollinating needs? Can we provide better solutions for the needs of native bees? The author provides some answers to these questions, but I think her underlying goal is that we join her on a journey to a better understanding and appreciation of the diversity of bees, especially native bees.

Excerpted from the Spring 2018 Arboretum Bulletin.

Garden Tip #132

Yellowjackets are at their most aggressive in late summer so it is understandable that people want to destroy their nests. Before you pull out the can of pesticide, remember that wasps are considered beneficial insects that eat plant-eating bugs, and will only inhabit their nest for one season. This article from University of Minnesota Extension gives good advice on how to deal with these insects.