Naturally Bug-Free (6 page)

All of these caterpillars were collected by a mud dauber (
Sceliphron
sp.), which paralyzed the plump morsels and stashed them in the nest chamber along with an egg. The dauber's baby will feast on the caterpillars as it grows. Photo credit: Brian Cooper.

Instead of spending your money on insects, why not spend a bit of time encouraging the good bugs you already have to stick around and reproduce? Many depend on flowers during some stage of their life cycle, so you can encourage them just like you did native pollinators by ensuring you have copious pollen and nectar sources available throughout the growing season.

In fact, you might receive double the benefit from any nest sites you put out for your native pollinators. Brian Cooper erected mason-bee blocks in his garden, and ended up encouraging mud daubers by providing wet mud nearby. Brian wrote: "When we went to harvest the bees, we found mud daubers also laid eggs in some of the unused cells. They collect food for their young inside the cell before they cap it with mud. I found one cell that was filled with caterpillars and a dauber larvae, and another cell with a pupa of the mud dauber and just bug parts left over."

Dragonflies (and toads) need a small pond in which to lay their eggs.

Weedy edges will also encourage predatory insects since the predators need to be able to find lots of insects to eat even when your garden pests are under control. In addition, dragonflies need a pond into which they can lay their eggs, and many insects will benefit from having a very shallow body of water from which they can drink. When attracting predatory insects, it's imperative not to use any pesticides (even organic ones) and to allow low levels of pest insects to fly under your radar. If there aren't any bad bugs around, your predatory insects won't have anything to eat and will go somewhere else.

Assassin bugs, like this immature wheel bug (
Arilus cristatus
), use their long mouthparts to suck other insects dry.

In fact, you've probably sensed a theme throughout this chapter. To encourage the good bugs, let nature move into your garden. Leave things alone and the beneficials will come.

Chapter 3: Garden vertebrates

The last chapter may have made it sound like good bugs are the holy grail of bad-bug control. However, it also helps to pay attention to the wider ecosystem when managing populations of pest insects. Even though you may not realize it, your bug problem might have actually started with a decision to eradicate snakes from your orchard or turtles from your tomato patch. So I'll spend a bit of time answering the question: Which vertebrates are friends and foes in the garden?

Wild vertebrates

Deer are one of the few vertebrates with no redeeming value in the garden.

I'm going to skim over large mammals since most people are familiar with these creatures and will soon learn which ones are helpful or problematic in the garden. Here in southwest Virginia, deer are our worst large-mammal problem, but bloggers in South Africa report monkeys tearing apart their gardens, wild boars root up Japanese gardens, and parrots (instead of mammals) wing in to eat Australian gardens to the ground. Among slightly-smaller American mammals, woodchucks (aka groundhogs) and rabbits are also problematic garden browsers, while skunks are mostly beneficial (although they can root up the garden inappropriately while trying to find their favorite foods: beetle grubs and cutworm larvae). In general, I suspect most of us would prefer for all large mammals to steer clear of our gardens.

This shrew, caught by our dog, was actually a beneficial part of the garden ecosystem.

Then there are the small mammals, which mostly consist of little critters that look like mice to the untrained eye. Small mammals can be good, bad, or neutral in the garden, so it's handy to know which animal is which.

Voles are mice-relatives that tunnel through the garden, gnawing on potatoes and carrots, eating the bark around the base of young fruit trees, and generally making trouble. You can tell voles from other small mammals by their rounded bodies, long fur, small ears, and short tails. We've found that a good dog and cat can provide quality vole control in the garden, although you may have to put up with churned earth where your dog obsessively raced the vole back along its underground tunnel.

Shrews and moles are often blamed for the damage done by voles, but these species are insectivores and live almost entirely by eating both good critters (like earthworms) and bad critters (like slugs) in your soil. Shrews can be distinguished from voles by the fact that their ears are concealed by fur and their teeth are often stained brown. Moles are larger, with long-nailed, paddle-like front feet used for digging, and with eyes and ears concealed by fur. Mole tunnels are another giveaway that you're dealing with insectivores—in addition to the shallow runways that voles also create, moles excavate deeper tunnels, then mound the earth on the surface.

Unless you're trying to create a perfectly flat lawn, you should be happy when you see signs of shrews and moles since they prove that your soil ecosystem is in balance. You can encourage voles and moles in the same way you encourage smaller soil workers—by feeding the soil with rich organic matter but otherwise leaving the earth alone.

The last type of small mammal you may notice in the garden is bats. These aerial predators eat large quantities of flying insects, so they can make their hunting grounds more habitable to humans. Bats don't have much impact on the garden itself, though, so I'll leave you to research more about these fascinating furry fliers on your own.

Wrens (top photo) and phoebes (bottom photo) are common garden residents that eat insects, among other foods.

Like small mammals, birds can be either good or bad in the garden. Despite stories about crows digging up sprouting corn kernels and cardinals eating the fruits from berry bushes, most birds we see in our garden seem to be acting as beneficial predators near the top of the garden food chain—in other words, they're eating insects.
Edible Forest Gardens: Volume 2
, by Dave Jacke, lists the following birds as particularly beneficial in the garden for their insect-consumption skills: swifts, woodpeckers, flycatchers (including the phoebe, which is a common garden resident in the eastern U.S.), vireos, chickadees, titmice, nuthatches, brown creepers, wrens, bluebirds, wood warblers, tanagers, and orioles. As an added bonus, I've noticed that birds enjoy perching on stakes and trellises in the garden, depositing their manure around the bases of the plants below.

This downy woodpecker is pecking apart a praying-mantis egg case, but woodpeckers are also prone to eat borers and codling-moth larvae on fruit trees.

Woodpeckers deserve a special mention since they seem to be good friends of fruit trees. In
Organic Orcharding
, Gene Logsdon reports that promoting woodpeckers by leaving natural woodland adjacent to your orchard can reduce overwintering codling moth larvae by 52%, and one of our readers emailed that woodpeckers in his yard were eating borers in his apple trees. Like some other birds, woodpeckers are cavity nesters, so they can be encouraged with appropriate birdhouses, or by leaving standing-dead trees outside your garden perimeter.