Caution sign of pesticide spraying

An insect infestation can trigger panic in anyone—especially when a serious pest threatens your home or garden. And while we might be tempted to reach for anything that promises to stop whatever is causing the destruction, it’s worth hitting “pause” on this impulse to dig a little deeper. When it comes to pesticides, the promise of a quick fix often comes with unintended consequences. In some cases, the chemistry of the product is more harmful than the intended pest.

Don’t be fooled—pesticide chemistry is serious business. Even “eco,” “organic,” or “natural” pesticides need due diligence to ensure the product you choose won’t have harmful side effects on your health or your environment. The number one rule when considering or choosing pesticides is to read the label.

The law requires pesticide labels to provide information about safe use, storage and traceability. To determine which pesticides are the most effective and the least toxic to apply, it’s worth carefully reviewing a few areas on the label prior to bringing a pesticide home.


Signal Words

The words “danger,” “warning,” and “caution” are likely familiar to anyone who uses basic household cleaning products. These words are the first indicator of how toxic a product will be to humans and animals. If there are two products that control the same pest, signal words can help you choose which one is the least toxic. Here are standard terms ranked in order of the most toxic to the least toxic.

Danger Poison Highly toxic by any route into the body.
Danger Can cause severe eye damage or skin irritation.
WARNING Moderately toxic either orally, dermal, or through inhalation; causes moderate eye or skin irritation.
CAUTION Slightly toxic either orally, dermal, or through inhalation; causes slight eye or skin irritation.

Active ingredients

As a horticulturalist, the first thing I look for when I pick up a bottle of any chemical compound at a store are the “active ingredients.” What exactly am I putting around my home? You might want a product to get rid of ants, but what’s the active ingredient that’s going to do the work?

By law in Canada and the US, the formulation of the pesticide must be on the face of every pesticide container, listed as “Active Ingredients” or “Guarantee.” Each active ingredient is identified by its common name. The concentration is listed as the percentage by weight or volume.

While these names may not be part of your regular vocabulary, a quick search on your smart phone will help you find the LD50 rating and details of any health concerns. You can do a pesticide label search on your mobile device. Health Canada offers online searching or searching via apps. In the US, you can search online through…