Spraying Pests In the Organic Garden
No matter how carefully you control growing conditions with healthy soil and proper watering, no matter how well-thought out your integrated pest management system, no matter how lucky you’ve been in the past, sometimes a pest problem arises in your garden that requires spraying the little buggers. What you spray and how you spray can make all the difference.
Most organic gardeners prefer sprays that break down quickly in the environment or opt for homemade products that make the plant unpalatable or difficult for the insects to populate. These sprays are often made of garlic, cayenne and other peppers, as well as strong scented herbs. The idea is to confuse the insect’s sense of smell (which is often located in their feet) and make them think they are where they don’t want to be. They’re often the organic gardeners first line of defense when pests are spotted.
The second line? Citrus oils, diatomaceous earth, even compost tea are known to work on some insects. Then there are the manufactured products you can make at home that suffocate the pest or make their environment inhospitable. These include soap solutions, often made at home and horticultural oils. Then there are other solutions including those with baking soda, alcohol, and ammonia. Boric acid is a well-known deterrent for migrating insects, one that acts as a stomach poison. Bleach is used especially in greenhouses to disinfect and control diseases. These ingredients are toxic unless diluted and dangerous if not handled correctly.
Botanical pesticides derived from plants have been used since before the development of synthetic pesticides and new ones designed for the natural gardener seem to pop up all the time. One of the most effective natural spray solutions we’ve ever used involved the pest themselves. Taking a tip from a fellow gardener, we ground up a bunch of the beetles that were attacking our beans in an old blender (no more margaritas from that appliance!) and sprayed the involved plants. The beetles disappeared and the plants recovered. Since then, the EPA has warned that bug juice may contain pathogens and might be unhealthy for humans. As in many things involved in the organic garden, more research is needed. Err on the side of caution.
The list of “natural” pest controls is long and constantly growing. We’ll be looking at more of the things you spray in detail over the coming weeks. But for now, let’s talk about how to spray. Some precautions always need to be taken, no matter how safe the spray. And how you apply the spray has a lot to do with how effective it will be.
Consider the size of your job. A hand-held, pump sprayer like the kind window cleaner is dispensed from is perfect for small jobs. If you’re using sprays that aren’t poisonous, like garlic-herb concoctions, citrus oils, or soap mixtures as well as chemical-based or otherwise harmful biological pesticides, use different sprayers for each. And always wear rubber gloves when using the latter to prevent contact with the skin. Be extra careful to keep even natural sprays made with garlic or chile peppers from your eyes. Manual pressure sprayers — the kind you pump — work well for larger areas. Be sure to clean it thoroughly after each use.
If you’re using pyrethrins or another chemical dust, use a hand duster designed expressly for that purpose. They cover better and allow better direction of the dust. Just sprinkling these powders on plants isn’t very effective. Using a duster, with its puff of air, not only covers better but forms a miniature cloud around your affected plant leaves.
For non-chemical dusts like diatomaceous earth, place the dust in a small paper bag in which you’ve punched several small holes and shake it over the affected areas. You can also put the dust in an old sock and beat it with a stick but we’ve found this method tends to be less accurate as the sock swings wildly with each blow.
There are several good sources of information for using various plants, household product, and chemicals that work naturally, including Barbara W. Ellis and Fern Marshall Bradley’s The Organic Gardeners’ Handbook of Natural Insect and Disease Control, Dead Snails Leave No Trails by Loren Nancarrow and Janet Hogan Taylor and Natural Pest Control: Alternatives to Chemicals for the Home and Garden by Andrew Lopez. Better yet, share your experiences using natural pest controls with us… please!