Image above: A caterpillar devouring leaves in a garden. From (http://chiquibaylon.net/2009/11/garden-pests/).
By John Michael Greer on 22 September 2010 in Archdruid Report -
(http://thearchdruidreport.blogspot.com/2010/09/animals-iii-unwanted.html)
In the sort of imaginary world where candy canes grow on trees and financial crises caused by too much debt can be solved by adding even more debt, the only animals a backyard gardener would ever have to deal with would either be small livestock who keep the refrigerator full, or helpful critters from the surrounding ecology who come fluttering or slithering in on cue to pollinate plants, turn plant matter into compost, and generally make themselves useful to the garden and the gardener. Alas, we don’t live in such a world, and if you have a backyard garden, you’ll be dealing with plenty of other animals whose goal in life is to eat the food you grow before you can get to it.
Call them the Unwanted. If that sounds like the title of a second-rate Western, that’s not wholly inappropriate, because most American gardeners seem to think of them in terms borrowed from Hollywood cowboy flicks: your garden is the inevitable happy but helpless Western town, the animals we’re discussing are the black-hatted bandits, and you’re the gunslinger with the tin star on your shirt who stands there in the middle of Main Street waiting for the baddies to show up, with both hands hovering over the grips of your six-sprayers.
Popular though the image is, it’s not a useful approach to managing a garden ecosystem. The idea that you ought to control unwanted animals by squirting poisons all over everything may not be the dumbest notion in circulation these days, but it’s arguably pretty close; a healthy garden, remember, is one with a diverse population of living things in balance, and the toxic compounds too many gardeners like to spray all over everything are just as deadly to bees and other helpful creatures as they are to the ones you think you need to get rid of. Most of them aren’t exactly healthy for you, either, and dumping poisons on your own food supply is not generally considered to be a bright move.
For that matter, it’s not even an effective way to get rid of the critters you don’t want. It’s important to understand why this is the case, because it points up a crucial difference between the unhelpfully mechanistic approach that governs so many activities in contemporary industrial society, on the one hand, and the ecological approach that ought to guide your work as a green wizard, on the other. Imagine, then, a big field full of a single crop, sprayed regularly with a chemical poison to keep some insect or other from dining on that crop. In ecological terms, what do you have?
What you have is a perfect environment for any insect that can learn to live with the chemical poison. That insect is looking at an abundant food supply, helpfully guarded by a chemical “predator” that will take out other insects who would otherwise compete for the same food supply. Offer evolution a chance like that, and it won’t be slow to take you up on the offer – which is why losses to insect pests for most crops in the US have risen to levels not far below those that were standard before chemical pesticides came on the market, even though most pesticides are being used at or above their maximum safe dosage per acre.
It doesn’t help any that nearly all chemical pesticides are single chemical compounds, each of which interferes with the biochemistry of its intended target in one and only one way. The fetish for chemical purity that runs through so much modern technology has many downsides, and this is one of them. Plants that have evolved chemical defenses against insect predators use as many as a couple of hundred substances that attack an insect’s biochemistry at many different points, an approach that makes it extremely difficult for ordinary random mutations in the insect population to work around them. Rely on a single compound with a single chemical pathway, though, and you make things easy for evolution; one mutation in the right place is all that’s needed, and sooner or later the luck of the draw will go in the insect’s favor.
The same bad habit, interestingly enough, lies behind the explosion of antibiotic-resistant bacteria in recent years. Any given antibiotic relies on a single effective substance with a single impact on the bacteria it’s supposed to combat; even the sort of antibiotic cocktail used so often nowadays has only two or three active ingredients. Compare that to St. John’s wort (Hypericum perforatum), which is best known these days as an antidepressive but had a much bigger role in traditional Western herbal medicine as a medicine for wounds, and contains dozens of antibacterial compounds – hypericin, rottlerins, xanthones, procyanins, resins, oils, and more. It’s precisely this complexity that makes it impossible for microbes to evolve resistance to herbal treatments.
Crusaders on their way to the Holy Land used to take a wineskin, stuff it with St. John’s wort flowers, and fill the skin with olive oil; by the time they got to where the fighting was, the oil was blood red, and they used it to dress sword wounds to keep them from festering in the not exactly sterile conditions of a twelfth-century military camp. American laws being what they are, I would probably get in trouble for practicing medicine without a license if I encouraged you to consider herbal remedies such as St. John’s word for infection, or even recommended that you read such excellent books on the subject as Stephen Harrod Buhner’s Herbal Antibiotics, so of course I’ll do no such thing.
The same logic, though, can be applied with a good deal less risk of legal trouble to a backyard garden. Instead of trying to get rid of unwanted creatures in your garden by the simple-minded and easily circumvented approach of a single poison, you need to change the environment so that it no longer encourages the Unwanted to hang around. That isn’t as easy as squirting poison all over everything; it requires you to learn about the life cycle and environmental needs of each of the creatures you intend to discourage, and to figure out ways to deprive them of things they need, make your garden welcoming to things that eat them, irritate, annoy, and frustrate the living daylights out of them until they throw up their forelimbs in despair and go bother someone else.
Sometimes a few simple things will do the trick. One classic way to keep raccoons from eating your sweet corn before you get to it, for example, is to intercrop the corn with some vining plant that will twine all around the cornstalks. Raccoons hate unstable footing, and the tangled, sliding mess of vines you’ll get around your corn will often annoy them enough that they’ll settle for the contents of your neighbor’s garbage can instead. Combine that trick with other methods of making life annoying for raccoons – for example, raccoons detest baby powder, and this can be sprinkled liberally on corn ears and leaves to make them leave corn alone – and barriers of the sort raccoons can’t easily get past – for example, once the silks have turned brown and pollination is over, you can cover individual ears with old knee-high stockings held on with rubber bands, and – and the fellow in the bandit mask isn’t likely to bother your corn much.
Some insects, similarly, can be dealt with by the simple expedient of physically removing them. On a large farm this would be a herculean task, to be sure, but in a small intensive garden, it becomes workable. Japanese beetles, for example, can be handpicked off your vegetables; do it first thing in the morning, when they’re still groggy, and put a tarp on the ground under the vegetables to catch those that fall off. In effect, you become an additional predator of Japanese beetles, and put enough pressure on their population to keep it from getting out of control.
In much the same way, one very effective way to limit the number of slugs in your garden is to find the places they like to hide in the daytime and remove these, except for one nice convenient board left flat on the ground in the middle of the garden. Every day, go out and gather up all the slugs that have hidden under the board, and feed them to your chickens, who will be delighted by the treat. (Those gardeners who lack chickens can drop the slugs into a pail of salted water.) Do this regularly and you’ll keep the slug population of most gardens down to the point that damage to plants is minor at best.
Not all problems with the creatures who want to eat your vegetables, or for that matter your animals, can be solved that easily. Any gardener worth his or her salt has a couple of good books on pest control, and takes the time to learn as much as possible about the habits and weaknesses of insects, mammals and birds who have to be controlled if you’re going to get food out of your garden. A few good over-the-fence conversations with local gardeners can also clue you in to methods that have been evolved locally. A garden notebook, kept up to date with notes on what works and what doesn’t, is another valuable resource.
Perhaps the most important resource, though, is the awareness that in planting and tending a garden you’re working with an ecosystem, not running a machine. Machines require purity; ecosystems thrive on diversity, which is the opposite of purity. This means that you should have many different crops growing in your garden at any given time, and they should be intercropped rather than grown in nice neat blocks, so that an insect or a plant disease that gets started on one plant can’t simply hop to the next one. It means that you should be prepared to use a series of partial deterrents when something that likes to eat your vegetables gets out of balance with the system, rather than attempting a knockout blow that may just knock out something you need.
It also means that you need to accept that a certain number of your plants are going to get sampled by other living things, and concentrate on keeping that number within acceptable limits, rather than trying to drop it to zero. You may not want raccoons and slugs in your garden, but they play necessary roles in the wider ecosystem, and as a green wizard – rather than a poison-toting sprayslinger – your job is to learn to work with that wider system in ways that work for all concerned.
Resources
Two excellent books on keeping your vegetables safe from your rivals are Rhonda Massingham Hart’s Bugs, Slugs, and Other Thugs and Helen and John Philbrick’s The Bug Book. Most organic gardening books also contain useful hints on keeping the Unwanted at bay, while books on raising small livestock such as chickens and rabbits almost always discuss ways to keep predators from dining on your animals before you do.
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