Sebastopol gardener shares why killing garden pests may be a bad thing

Sebastopol biologist, gardener and writer Frederique Lavoipierre is on a peacekeeping mission.

The former education director for Santa Barbara Botanic Garden wants to convince us to lay down our arms against the insects we fear are invading our gardens. We need to declare a truce, she says.

Rather than labeling the tiny creatures that crawl over or alight on our plants as friends or as foes to destroy, think of them all as allies, she says, each with a role in keeping your garden in healthy balance. Even aphids and other so-called pests provide food for other critters that we do want to inhabit our gardens.

For 10 years, Lavoipierre wrote a column called “Garden Allies” for Pacific Horticulture Magazine, focusing on wildlife visitors to the garden. She was persuaded by Timber Press to compile those columns, along with a few new essays, in a new book, “Garden Allies: The Insects, Birds & Other Animals That Keep your Garden Beautiful and Thriving.”

The book is illustrated with delicate black-and-white drawings by Craig Latker, a landscape designer and illustrator who has done work for The Nature Conservancy, Sunset Books and University of California.

Lavoipierre’s point? As much as possible, maintain a live-and-let-live approach to your landscape and its inhabitants and nature will, in most cases, take care of the rest.

“I think of everything as prey and predators. Everything is food for something else,” she says.

On a recent walkabout at Sonoma Garden Park, a thriving habitat garden tended by the Sonoma Ecology Center, Lavoipierre noted that there are probably thousands of species of insects going about their daily business in this one garden.

During her five years in Santa Barbara, when groups would come to the garden, she frequently pointed to a big live oak tree and said, “There are 800 species of insects eating that oak tree, eating every part of it. The leaves, the acorns. They’re under the bark; they’re under the roots, but we don’t see them because insects are really good at hiding from predators. They’re tasty little morsels.”

Lavoipierre believes many books and other information sources about so-called “integrated pest management” are too complicated for the average gardener. They often suggest that we try to identify everything that flits, crawls or slithers in our yards — something that’s impossible even for an expert.

“Even most entomologists specialize in just a small group of insects because there are so many,” she says.

Healthy habit

Encourage a good habitat in you garden and you won’t have to put much effort into controlling insects, according to Lavoipierre. They’ll take care of it.

“It’s a whole food web. If you decide every time you see an aphid that you’re going to get rid of it, then what are the ladybugs going to eat? What are the lacewings going to eat? You have to have some of everything. If you’re a hummingbird, you want aphids to feed your babies.”

Lavoipierre recommends including a wide variety of plants in your garden, of varying sizes and types, including things like bunch grass. Also, non-native plants are more prone to pests and diseases, so make sure you have a good selection of native plants, she says.

“I try to create a lot of little micro habitats (and) layers,” she says. “Perennials, shrubs and trees. Perennial grasses are fantastic. They provide a wonderful habitat at the base. Ladybugs sometimes will overwinter there.”

Of course, Lavoipierre does have her limits. She doesn’t want aphids on her rosebuds or cabbage plants.

But rather than killing them with pesticides, she will wash them off with a blast of the hose. Vegetable crops can be protected from invading caterpillars or leaf miners with row cover.

And she does resort to Sluggo, a mild organic pesticide, to deal with voracious snails and slugs. She also may use Sluggo on earwigs, which are not native and have no predators here. But she tries to be patient because very often, Mother Nature will take care of the problem.

Lavoipierre recalls that once, many years ago, she noticed an infestation of whiteflies on her currant bushes. At the time, she thought she should do something about them but promptly forgot. When she checked the plant much later, all of the aphids were gone and the currents were ripe and ready to eat. Something else had feasted on those aphids.

Another time, she discovered a colony of aphids crawling all over her bank of lupine. She came back the next day and found a battalion of soldier beetles devouring them.

Watching her garden carefully, sometimes with a looking glass, taught her many lessons, such as the benefits of leaving a bare patch of dirt along the edges of walkways for the solitary bees that are ground dwellers.

Think before you attack, she cautions gardeners. Is it just a few insects on a plant? That’s unlikely to be a problem. But if the plant is covered, it may be an infestation that will require some nontoxic eradication.

Early fascination with insects

Lavoipierre was born in Liverpool, England, to a French mother and a South African father who was an entomologist. The family lived in Singapore for several years and then moved to the U.S. and eventually settled in Davis, where her father was a researcher at the university.

“He loved insects, so when we would go out in nature we were always looking for beetles and moths and butterflies,” she says. “So I got my interest when I was little. Out in the garden, he would show us lacewing eggs.”

Lavoipierre came to Santa Rosa Junior College to study biology and horticulture and later went to Sonoma State, where she earned a master’s degree in biology with an emphasis on ecological principles of sustainable landscapes. While there, she became the founding director of the SSU Sustainable Landscape Professional Certificate Program, through which she coordinated the Garden Classroom and Entomology Outreach programs.

Her fascination with insects has informed so much of what she teaches and writes about.

She encourages people to leave something for the wildlife. Those spent sunflowers are food for many insects. When your herbs start to flower, don’t remove them all. Leave a few as fodder.

“Insects are key partners in maintaining the web of life and in supporting healthy gardens,” writes Lavoipierre, now a consultant who splits her time between Sebastopol and a temporary home in Walla Walla, Washington. “Without insects and the intricate relationships that connect them to plants and to other organisms, all life would ultimately collapse.”

A third of the food we eat, she notes, is dependent on pollination and pollinating insects. But just as important are the insects that provide food for other critters and regulate pest populations.

“This is a fantastic garden to come to if you want to see a good example of a really diverse garden,” she says at the Sonoma Garden Park, which spreads over 6 acres at 19996 Seventh St. E. in Sonoma. As she makes her way among the rows of ornamentals and raised beds, she frequently stops for a close-up look.

“Here’s a swallowtail. It’s very likely laying eggs on celery. Go ahead and lay eggs there,” she tells the creature. “And here’s a wasp, hunting around probably looking for caterpillars.”

Her rule of thumb is: If it’s not doing damage, leave it alone.

Even the dreaded wasp can serve a purpose.

“People hate them. But I tell people these paper wasps actually prey on caterpillars,” Lavoipierre says. “So if you have a paper wasp nest and it’s hanging over your front door, you want to get rid of it. But if it’s in the backside of the garage or a side yard, maybe you just leave it. If you’re lucky, they’re getting your cabbage butterfly caterpillars.”

It’s all about thinking differently about the insects that inhabit the garden.

“Everybody is interested in bees and pollinators,” she says. “Now let’s take the next step and look at the insects that are preying on pests and what they need. And one of the things they need is those pests.”

You can reach Staff Writer Meg McConahey at 707-521-5204 or meg.mcconahey@pressdemocrat.com. OnTwitter @megmcconahey.