Dosage makes the poison: Read herbicide labels


By Ethan Proud | PREVIEW Columnist

“Dosage makes the poison” is an old adage that holds true today. A little bit of something might be good for you, but a lot of it can cause problems. 

The same goes for herbicides. When used properly, they can have zero to minimal nontarget damage and support native biodiversity. When used incorrectly, they can cause a myriad of issues. For example, some herbicides are safe around trees, while others are not and can kill your brand new planted maple tree or, worse, a mature tree.

So, how do you know how to use the herbicide you just purchased? The label is the material affixed to the container and contains all of the legal uses and restrictions for the product. Not following the label directions is a violation of federal law. The label will instruct how much herbicide to use on which plants and how to safely treat around water, sensitive plantings and more. The label will also cover what protective equipment you need to wear while making the application.

Reading the label is the second or third step in making any herbicide application. The first step is to determine if you need to use an herbicide in the first place. Some considerations for whether to use an herbicide or not include: 

• What is the target species?

• How much of the target species is present?

• Can it be removed manually?

• Is manual removal time effective and economically efficient?

From there, the second step is herbicide selection and then reading the label or perhaps reading the label and then making a decision depending on your knowledge of the products available.

Once you have made your herbicide selection, you need to determine if the timing is correct or if you need to wait. Some herbicides have pre-emergent properties and can be used in the spring prior to germination or in the fall prior to the ground freezing. Some herbicides will offer species specific information such as: effective on seedlings at X rate, increase rate to X for mature plants or treat during full bloom to senescence. 

The next step is to determine your output method. Here we are assuming that you are using whatever equipment you have on hand, whether it is a handheld sprayer, backpack sprayer or an ATV-mounted sprayer. Your output method is either spot treatment or broadcast. Treating one property you might use both methods. Broadcast spraying is great for either large populations of weeds or in areas where the chance of nontarget damage is little or nonexistent. Spot spraying is preferred for sites adjacent to sensitive areas or areas with susceptible desired vegetation. Spot spraying is also a more kind option for your wallet as it decreases the amount of herbicide you need to use, though it may be more time-consuming.

All in all, the label provides the most accurate information on how to use an herbicide product. If you have questions on how to interpret the label, please reach out to the Archuleta County Weed and Pest Department. You do not have to have purchased the herbicide from us to request help.

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