When Good Pesticides Do Bad Things

Gardeners have a tendency to believe that organic products are always safe. After all, doesn’t “organic” sound down-to-earth, homey, and friendly? But when referring to pesticides or fertilizers, organic really only means the product was derived from natural sources rather than synthetic (read “chemical”) ones. And Mother Nature can pack quite a wallop: toxic products abound in the wild. Think of strychnine and cyanide.

That’s why a gardener interested in maintaining a healthy environment shouldn’t spray pesticides indiscriminately. If the product is a pesticide (therefore, if it kills pests), it’s doing some kind of damage. You can just as easily kill beneficial or harmless insects like ladybugs, bees, and butterflies with rotenone (an organic pesticide) as with imidan (a synthetic one).

Safer Use of Pesticides

Here are a few tips on treating insect pests while causing the least amount of disturbance to the environment.

1. Use the least toxic product possible under the circumstances. You can handpick caterpillars when they aren’t numerous… and you’d be amazed at how readily spraying with plain water can knock pest insects off their hosts. Soaps and oils are also fairly safe pesticides (they aren’t poisons, but kill by inhibiting the pest’s breathing): just don’t spray them directly on non-target insects.
2. Use traps or barriers to keep pests away in the first place: a collar of cardboard can keep cutworms at bay and covering a crop with floating row cover will prevent many pests from reaching their host plant.
3. Read the label each time you use a pesticide: it may include special precautions on its safe use you need to put into effect.
4. Treat only the plant that has the problem, not all the plants in the area.
5. If possible, don’t spray pesticides on blooming plants, as they’ll likely be visited by beneficial insects.
6. If you have to treat a blooming plant, try to apply the pesticide when pollinators are not present: early in the morning, for example, or in early evening.
7. Don’t spray pesticide on a windy day, as it may be carried to other plants.
8. Don’t spray pesticide when rain is in the forecast either, as not only will it wash off and be ineffective, but the run-off can harm soil insects or even pollute nearby bodies of water.
9. And – probably the best advice of all – when possible, choose plants that are naturally pest resistant. After all, if it doesn’t attract pests, you won’t need to treat it!