Bugs are part of gardening. Some are beneficial to our plants, some are detrimental, and most just exists in our spaces along with the rest of nature. And while we support natural gardening and working within the ecosystem around you, some insects are do serious damage to our plants. Vegetable gardeners know this all too well—we’ve all had to deal with squash beetles, vine borers, or hornworms. There are times when a pesticide becomes necessary, but the good news is that there are environmentally friendly options for us that can be effective in keeping our plants and our world safe and healthy. Let’s dig in and learn more about natural pesticides, biopesticides, and their role in our gardens.
Natural Pesticides and Biopesticides
Let’s start as we often do by offering a few definitions for core concepts. Natural pesticides—also known as “organic pesticides”—are substances derived from natural sources that have a pesticide effect when used on plants. These natural sources may be plants—neem oil, ryania, or marigold extract—or the may be mineral in origin like cryolite or diatomaceous earth. For the most part natural/organic pesticides are insecticides, meaning that the work to either kill offending insects or otherwise disrupt their life cycles.
Biopesticides (sometimes styled “bio-pesticides”) are a particular subset of natural pesticides, and are a bit more complex to define. These are pesticides derived from natural sources—including plants, minerals, animal sources, or microorganisms—that control rather than eliminate unwanted pests in the garden. Biopesticides have a very limited range of biochemical actions and decompose quickly, making them far safer than conventional pesticides. Examples include Bacillus thuringiensis, or Bt, a bacterium that is often applied to plants in order to kill insect larvae. This prevents the population from growing and taking hold, thus saving the plants in a natural and environmentally-friendly way. Other substances may be used—including such unlikely candidates as baking soda and canola oil—with a variety of effects including repelling insects altogether, disrupting their mating cycles, luring them into traps, or attracting competing or predatory species.
Both natural pesticides and biopesticides are safer for both us and the environment than conventional pesticides, however they should still be used with a degree of caution. Follow the instructions on the label in order to get the best results for both you and your plants.
Using Natural Pesticides and Biopesticides in Your Garden
While you should always use any garden product per manufacturer’s instructions, we would like to offer some basic guidelines as to which natural pesticides or biopesticides to use for specific pests. This is just a general guide to get you started; as always we recommending checking with your local garden club or county extension office for local advice.
- Pyrethrin: a great insecticide for aphids, beetles, and caterpillars
- Neem oil: A repellent, fungicide, and an insecticide, it works well for a wide variety of insects including mites, whiteflies, and locusts. Also a potent mosquito repellent, but generally not used directly on human skin.
- Rotenone: much like pyrethrin, it affects leafhoppers, beetles, and aphids
- Sabadilla: a plant-derived repellent for caterpillars and leafhoppers
- Sulphur: a fungicide, works great for mold issues and especially powdery mildew
- Kaolin clay: functions as an insect repellent, keeps unwanted guests from taking up residence in your plants.
- Diatomaceous earth: good for crawling insects, slugs, and snails. It functions as a desiccant and dehydrates them.
- Bacillus thuringiensis(Bt): effective against caterpillars and certain types of worms. Generally applied as a liquid spray but some powdered forms exists.
- Spinosad: used for a broad spectrum of insects including thrips, leaf-miners, and fruit flies.
As always we encourage you to do a little research with other local gardeners or horticultural agencies and learn what works best in the area where you live, but these are all strong options and widely available in garden stores around the US and Canada.
A Natural Approach to Pest Control
We hope this blog gets you started on the path of natural pest control and natural pesticides. Our gardens are part of nature and we believe that we should work within it rather than against it. By embracing organic pesticides and biopesticides along with other natural means of pest control, we can make our gardens, ourselves, and our world just a bit healthier and happier.
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