Safer ways to defend your garden from bugs
Let’s say you’ve just planted a garden and want to be ready when the insects attack. You’ll have no difficulty finding items at the garden supply store that promise to do the job. But you wonder–is this stuff safe? Well, pesticides and insecticides are less dangerous to humans than these products were back in days of indiscriminate spraying of DDT. But they are by no means safe enough to be used without extreme caution. And some products that are safe for humans can still wreak havoc on other creatures. Even some of the “natural” pest killers are not completely safe. What’s a careful gardener to do? Try the following less-toxic or completely nontoxic ways of defending the health and beauty of your lawn and garden.
- Prevention is better than cure.Before investing in insecticides, find out about ways to prevent pests from attacking in the first place.
- Keep plants healthy. Plants are really the same as people in one important respect. A person who is well nourished, in good physical condition, gets good care, and avoids stress, is less likely to get sick than someone who neglects nutrition and good health practices. For a plant, the first line of defense is fertile soil, a location appropriate to the plant’s needs, the right amount of water, and attention. Unhealthy plants lose their natural resistance to insects.
- Know thine enemy. If you do see something being attacked, first make sure you know which insect is doing the damage. Bring a sample of the ailing plant to a reliable, knowledgeable garden shop and ask. Or contact the nearest branch of your local U.S. Department of Agriculture Cooperative Extension Service. This agency has a wealth of information–and may be able to suggest a simple solution that doesn’t require application of insecticides.
- Kill ‘em with your bare hands. Or, well, gloved hands. If you catch them early, a lot of pest infestations can be halted by hand. When the tomato hornworms appear, for instance, pull them off your tomato plants immediately and smash them or drown them in soapy water. To get rid of snails and slugs, go out for a few moments at night with a flashlight and collect and kill them. You will quickly see their population diminish. A colony of aphids can be rubbed off with a cloth and soapy water.
- Water early. Watering at night leaves a damp environment that encourages mold and mildew. It also inspires invasions from insects, slugs, and snails.
- Rotate annual flowers and vegetables. Planting the same thing in the same place repeatedly makes it easier for insects that like a certain plant to get established.
- Confuse bugs with variety. Planting solid beds of the same flowers or vegetables can encourage insects. If you mix up the plants, you literally mix up the bugs because if the plant they love is next to one they hate, they don’t like to hang around. For example, cabbage worms hate tomatoes, so a tomato plant next to a cabbage plant will repel them.
- Prune properly. Many bushes, trees, and other perennials are more vulnerable to insects if they have dead wood, or if their branches are so close together that they don’t get sufficient ventilation. So, make sure they are properly pruned. Sometimes an insect infestation can be stopped simply by pruning away the infected part.
- Collar your seedlings. Just putting a circular band around a seedling, such as a tin can or a cut-up plastic bottle can afford a lot of protection for a delicate young plant, at no cost.
- Check your plants often. The earlier you spot an infestation the better. Take a good look at the backs of leaves, where many insects lay their eggs and begin their lives.
- Take ants seriously. While the bustling activities of ants have their charm, and they probably aren’t eating a plant, they “farm” other insects, such as aphids. Ants move parasites eggs and larva onto plants, and then tend to them. Among rewards for the ant are “milking” the parasites by licking off juices they secrete. Disgusting but true. So if you observe ants bustling up and down a trunk or stalk, check for the tiny insects that work for the ants. Then annihilate the ants as well as their employees.
- If you have a problem, first consider the least-toxic approaches.
- Use horticultural soaps. These are usually nontoxic and widely available. You can make you own simply by mixing a teaspoon or so of liquid dishwashing detergent in a gallon of water.
- Exploit sex in the insect world. Sexual attractants called pheromones lure insects into romantic encounters. There are various products baited with pheromones to entice and catch insects on sticky surfaces or in some other trap. If you’ve had an infestation in a previous year, put these traps out just before the insects emerge.
- Try BT. Bacillus thuringensis is a bacteria that infects and kills insect larvae. Be cautious in its use, however, as it could harm your beneficial insects. It is harmless to humans and animals.
- Stick ‘em up. There are sticky, tarry, or syrupy substances on the market that you apply on a plastic or rubber band wrapped around trunks and stalks. Insects that crawl up the plant from the ground simply can’t get past these gooey barriers without getting stuck in them and dying. It is effective against ants, cutworms, inchworms, gypsy moths, cankerworms, pecan weevils, obscure root weevils, forest tent caterpillars, and tussock moths, among other nasty pests.
- Then try botanicals. If you must use a pesticide, choose a botanical first. They are made from plants rather than synthesized in a chemical factory. Having withstood the test of time, botanicals are safer than many synthetic chemicals. They often contain one of the following active ingredients:
- pyrethrum, from a type of chrysanthemum, is a low-toxic choice, though some people might experience an allergic reaction. There are also synthetic pyrethrums that work the same way.
- rotenone, from the root of the derris plant, is very effective on aphids, beetles, and caterpillars. It is, however, very toxic to fish, so don’t use it near a fish pond. It doesn’t harm bees.
- sabadilla, from the seed of a type of lily, is nontoxic to humans, though it can cause sinus and lung irritation. Since it can harm bees, don’t apply it to blossoms, and apply it at night, when the bees aren’t foraging for pollen and honey.
- neem, from a tree, is most effective on moth larvae, and can also harm butterflies.
- As a last resort, the stronger poisons. A responsible doctor doesn’t use the most powerful antibiotics unless an infection is serious or life-threatening. The same principle should apply to your plant doctoring. If plants are so sick that you face a choice of letting them die or using a non-botanical, synthetic poison containing active ingredients such as carbaryl, diazonon, or malathion, make sure that you are getting the one that is most effective for your target insect. Use as little of these poisons as possible and carefully follow every precaution on the label.
When shopping, look for
- Clear, detailed directions. Make sure the labeling on the product lists its active ingredients, gives thorough instructions, and clearly describes whatever precautions should be taken for you and the plant.
- One of the best ways to control pests is to invite their natural enemies to your garden to feast on the criminals. The beneficial insects that feast on bad bugs are attracted by plants such as alyssum, yarrow, dill, and fennel.
- If you have had a persistent problem with flying insects, you can prevent them by getting nets or plastic covers to protect the plants. If you use the plastic, however, you’ll have to be careful not to overheat the plant, because the cover will act like a mini-greenhouse.
…to you and your health Creating a healthier garden without resorting to insecticides is not only safer, but can give you a more varied landscape. A border of flowers or herbs around your vegetable garden, planted to attract insects, has a beauty of its own. Mixing different plants together to frustrate insects will break up what might be a boring uniformity. …to your wallet Gardening the natural way, without insecticides, may cost you less in the long run because you won’t need to buy insect poisons and weed killers. And by keeping your plants healthy you may well enjoy bigger vegetable yields. …to the Earth Even when they considered safe for humans, pesticides can do grave harm to birds, fish, and wildlife. Avoiding the use of them will reduce your lawn and garden’s impact on the environment.
- Bug panic. Just because one plant is being hit by insects doesn’t mean they’re about to destroy your entire lawn or garden. Wait and see what happens before rushing out to buy an insecticide. In fact, using an insecticide could actually cause problems by killing beneficial insects like ladybugs, which devour harmful insects like aphids.
- Confusing good and bad insects. Just because you see an insect on a damaged plant, this doesn’t make it the culprit. In fact, it may be a beneficial insect that feasts on bad bugs.
- Bug zappers. Those contraptions that attract bugs to a light and then fry them can also kill off beneficial insects.
- The National Insecticide Information Center is an invaluable source for product information.
- Some of the most useful items in any garden shop are the books about gardening. What you can learn from them about safe control of insects can turn out to be worth many times the cost of the book.