Authors: Anna Hess
Volume 2 in the Permaculture Gardener series
by Anna Hess
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A praying mantis moved into a bed of buggy beans in search of a high-protein snack.
Insects are one of the worst problems facing many organic vegetable and fruit gardeners. For the last seven years, my husband and I have grown most of our own food, and some days I was ready to throw in the towel. Our squash plants melted into puddles of wilted leaves just before they set fruit (vine borers at work), tiny grubs defoliated our asparagus plants (asparagus beetles chowing down), and mysterious insects arrived in the night to eat our Swiss-chard leaves (striped blister beetles being bad). Our broccoli heads were so covered in cabbageworms that it seemed easier to toss the food than to eat it, and Japanese beetles dripped from our grapevines.
Our neighbors told us to spray, but even seemingly safe pesticides like Bt gave me the willies. Is there a way to grow our food without any chemical inputs at all?
The answer is yes, but only if you're willing to bend a little to nature's whims. A garden ecosystem is always going to be at least slightly out of balance because we've manipulated the soil and landscape to promote productivity, but we still can do our best to bring natural forces to bear against insect pests.
is full of the techniques I use in my own garden to keep pest insects in check without spraying anything. I hope they work as well for you!
(As a final side note before you delve into the meat of this book, I wanted to alert you to the glossary in the back. Now and then I'll use a term like "permaculture" or "Bt" and assume you know what I'm talking about. If you do—great! If not, just flip to the glossary for a quick refresher course on these advanced homesteading topics.)
Part 1: Good and bad bugs
Chapter 1: Pest-invertebrate identification
I was concerned when I saw the dark scales above on dead asparagus stalks, but I soon realized these were simply eggs of the innocuous katydid that sings me to sleep on autumn nights.
My first rule when dealing with garden insects is to identify everything I see. Many new gardeners assume every bug is bad, but the truth is that a significant number of the creepy crawlies you'll find on your vegetables are either random passers-by, are beneficial pollinators, or are predators of leaf nibblers. The trick is to know the difference, and to understand how larger animals fit into the complex web of garden life. While this book can't introduce every garden character, I can at least hit the highlights and help you find the resources to fill in gaps on your own.
Types of invertebrates
The most common types of invertebrates visible to the naked eye in a garden are annelids (worms), molluscs (snails and slugs), myriapods (centipedes and millipedes), arachnids (spiders and mites), crustaceans (sowbugs and crawdads), and insects.
When setting out to identify an unknown garden resident, it's handy to have a framework to fit them into. Most critters you'll find in your garden are known as invertebrates because they have no backbone. (I incorrectly call them "bugs" throughout this book when I'm not feeling very scientific.) The chart above shows the wide range of invertebrates you can find in most backyards.
In the next section, I'll introduce you to the worst garden pests in the U.S., but what should you do if your leaf nibbler isn't on that list? When I find an unknown denizen of the garden, I usually start my identification campaign with the internet. If you go to www.images.google.com and type in some identifying features, your pest's mugshot may pop right up. For example, when I saw my first asparagus beetles, I typed in "orange beetle on asparagus," and the species I was looking for turned up on the first row.
It's particularly handy to know the main types of invertebrates because a good search often includes the category of invertebrate, its color, and the plant the bug is found on. The picture at the beginning of this section introduces you to the major types of invertebrates found in a garden: annelids, molluscs, myriapods, arachnids, crustaceans, and insects. Among insects, the most common categories are beetles (with hard wing covers), flies (with only one pair of flight wings, the other wing pair having been reduced to knobs), true bugs (with sucking mouthparts and including cicadas, aphids, leafhoppers, and shield bugs), grasshoppers and their kin (including crickets and katydids), butterflies and moths (and the caterpillars that are their larvae), hymenoptera (ants, bees, and wasps), and dragonflies (along with the related damselflies). If you can tell these major groups of insects apart, you'll be well on your way to identifying the next unknown bug in your garden.
It's handy to be familiar with each stage of an insect's life cycle. The photos above all show Mexican bean beetles: eggs, a larva, and an adult.
If a simple image search fails, I turn to books next.
Garden Insects of North America
by Whitney Cranshaw is my favorite invertebrate field guide because its full-color photos usually help me narrow down my search quickly. Several other field guides to garden insects (or just to insects in general) exist as well, and any of these titles will help you identify your garden friends and foes.
But sometimes books fail me as well. At that point, I usually turn to www.bugguide.net, which is the Wikipedia of the invertebrate world. You can often identify an invertebrate (or at least get close) by working your way through bugguide's key, but if I'm thoroughly stumped, I instead log in and submit a photo, requesting identification help. One of the volunteers gets back to me within a day or two, telling me which species (or category) of invertebrate I've found. Those of you less technologically inclined may get the same results by capturing the questionable insect in a jar and taking it to your local agricultural extension agent for identification. (Visit www.csrees.usda.gov/Extension/ to find the closest extension agent to you.)
No matter how you identify the invertebrates in your garden, it's essential that you don't skip this step! I focused on insect identification first for a reason—you can't work to promote the good bugs and minimize the bad bugs if you can't tell them apart.
Worst garden pests
A survey by Mother Earth News showed that home gardeners' worst pests varied by location.
Although you probably won't be able to identify every invertebrate in your garden, it's worth knowing the worst offenders on sight. A
Mother Earth News
survey of 1,300 gardeners provided a list of the twelve worst pests in home gardens, which are divided up regionally on the map above. This section includes a quick run-down of the natural history and common treatment methods used for each pest. As you read, please keep in mind that many of the mainstream organic treatments mentioned in this chapter aren't quite as kind to the earth as a permaculture gardener might like—I'll suggest alternatives later in the text.