Read and follow label instructions.
This is an important phrase! It affects the safety and effectiveness of the products you use. Failure to read and follow label instructions can injure or kill you or others, lead to plant burn, harm beneficial insects and wildlife.
What exactly does it mean? How do we intepret the labels on pesticides?
Any pesticide, organic or otherwise, is labeled with one of the following words:
Those are in increasing levels of toxicity: Caution products are the lowest toxicity, Danger are the highest. The toxicity is based on direct harm the pesticide may cause by swallowing it, inhaling it, getting it on your skin, or getting it in your eyes. Tests are done to determine how lethal it is and how likely to cause skin or eye irritation.
Different products with the same active ingredient may have different Signal Words due to differing dilution rates of the concentrated or mixed solutions.
These give you a guide as to what makes a particular pesticide dangerous to you or others. It may be swallowing or inhaling the pesticide, absorbing it through the skin or eyes, or direct irritation from contact with the concentrate or mixed spray.
Personal Protective Equipment (PPE):
The label will tell you which protective clothing or gear to wear, how long you, children and pets need to stay out of the treated area. Most people fail to heed this, but it is key to protecting yourself and others from harm.
The label will state whether it is toxic to wildlife. Unfortunately, the impact on bees is not always mentioned. The likelihood of drift, runoff, leaching, and groundwater contamination may be mentioned. These are technical terms that you should understand before you apply the product.
You may not recognize the name, because a chemical may be better known by its trade name. Example: Daconil is the trade name of chlorothalonil. Manufacturers do not have to disclose the inert ingredients, but do have to list their percentage.
California’s Prop 61 requirement:
If an ingredient in the product, active or otherwise, is “known to the state of California to cause cancer” that must be on the label. It's up to you as to whether that matters to you.
Storage and Disposal
There are general instructions for how to dispose of partially used or empty pesticide containers. Where do you keep your pesticides?
What if you lost the label?
Nearly every company now puts pdf copies of their product labels online. Hey, you can increase the font size and actually read it!
Do organic pest control products have the same labeling?
Yes. Anything that is sold as a pesticide in California has to be labeled. Organic pesticides aren’t necessarily safer than conventional ones.
Here is an example of a commonly used home garden fungicide:
Monterey brand FRUIT TREE, VEGETABLE & ORNAMENTAL FUNGICIDE
“Active ingredient: chlorothalonil 29.6%” You may know this as Daconil, a trade name.
“Known to the State of California to cause cancer.”
Signal Word: “Warning.” Red flag. This is one of the more toxic products homeowners can buy. I always urge purchase and use of a Caution labeled product if possible.
Precautionary Statements: “May be fatal if inhaled. Harmful if swallowed or absorbed through skin. Causes moderate eye irritation. Avoid contact with eyes, skin or clothing. Do not breathe spray mist. Prolonged or frequently repeated skin contact may cause allergic reaction in some individuals.”
Now we know where the Warning label comes from. Given these specific warnings and that higher-toxicity Signal Word, it is important to use the exact protective equipment listed.
PPE: The following are required: long-sleeved shirt, long pants, shoes and socks, protective eyewear, specific types of waterproof gloves, an approved respirator with an organic vapor cartridge or canister with a specific type of filter. You should not even open the bottle until you are wearing all of these listed items.
“Keep children and pets off treated area until dry.” The sprayed material on the leaves can poison them.
Environmental Hazards: Chlorothalonil can kill aquatic invertebrates and wildlife, can drift to nearby water, can runoff into surface water for “several days or weeks after application.” It can leach into groundwater, even when used according to the label.
Directions for Use: These give specific rates of application for certain pests on certain types of plants, by name. The rates are not the same for every crop. Do not exceed them, as they are based on tested effectiveness and are the basis for how toxic the product is considered to be. In some cases they will tell you a maximum amount you can use per year.
The Preharvest Interval (PHI) tells you how many days before harvest you can apply it. These vary by crop (14 days for onions, 7 days for cabbage, day of harvest for carrots), so you need to check the label carefully.
“Avoid spraying plants during extremely hot and sunny weather.” This is because chlorothalonil, like many pesticides, can burn the foliage during hot weather. “Do not apply … within one week … of oil or an oil-based pesticide.” Same issue: you may burn the leaves when used in combination with oil.
Storage and Disposal: These don’t vary much from one product to another, but it is wise to read them. In particular, disposal of the empty container has specific requirements. When you use the last of the bottle, rinse it three times and pour the rinse water into the spray tank. Then puncture the bottle (to prevent re-use) and dispose of it according to local regulations. If you don’t know what those are, contact your local agricultural commissioner.
For some discussion of a new product for vegetables and fruit trees, here is a previous blog article: