Use organic pesticides with care

Created on 1/6/2010

I’m definitely an advocate of using organic pesticides whenever possible. The less toxic substances we dump into the environment the better, but I feel the need to stress to people that just because something is organic doesn’t mean it’s harmless. Many times they have less long term implications than synthetic chemicals, but it’s important to read the labels and use them properly. In recent studies, even some natural pesticides are shown to be carcinogenic.

One example that pops to mind is rotenone. The chemical in rotenone comes from the legume of a tropical plant. It is often used by native peoples to kill fish. They’ll peel and pulverize the root, toss it in the water, and wait for the fish to float to the top. Modern fish biologists use it to eliminate entire populations of fish from lakes, usually in a plan to reintroduce native species that are in danger of being pushed out or hybridized in the area. Rotenone interferes with the fishes’ ability to utilize oxygen, and is an effective means of starting over.

In the garden, it’s used to knock out aphids, Japanese beetles, cabbage worms, stink bugs, and a multitude of other creepy crawlies. Even though it’s been used for decades as a natural pesticide it is classified as “moderately hazardous” by the World Health Organization. There have been rare cases of poisoning in children, and there is an argument whether it causes Parkinson’s disease. A lot isn’t known about it, yet.

Pyrethrins are another organic option for many gardeners. This common substance is derived from a Chrysanthemum. Although a chemical coming from a daisy may seem safe, it can cause severe allergic reactions to some people who have asthma or are highly sensitive to these types of plants.

The other drawback with both pyrethrins and rotenone is they are non-specific on what they kill. If you dust plants with them, they’ll harm beneficial insects as well as the bad characters. It’s an important point to remember before reaching for them.

When using either of these two organic chemicals, be sure to read the label and follow the safety directions. They don’t print warnings for the fun of it. Wear gloves and long sleeves to keep it off of your skin, as well as a mask and eye protection. You don’t want to inhale either substance. These are tools for us to use, but we have to be wise about how we handle them.

On the other end of the spectrum, the commonly used insecticidal soaps are fairly safe around everyone. They’re made up of potassium or sodium salts that penetrate that break down the outer covering of the insect. Obviously, it has to have direct contact with the pest, and isn’t effective once it dries. Other than being careful on what plants you spray (some are more sensitive to it and can be burned) insecticidal soaps are fairly innocuous on the toxicity scale. You can spritz away bugs up until you harvest. Just be sure to wash the veggies before adding them to your salad.

Even with insecticidal soaps or other safer substances, such as Neem (a spray made from the seeds of the neem fruit), they’re not to be used indiscriminately. Choose the less toxic substance or techniques that will do the job with the least amount of repercussions