Know before you spray

Herbicides ineffective on some weeds


Springtime and summer mean weeds. For a lot of people, that means pulling out the chemical herbicide to spray the plants into submission instead of the hard work of pulling the weeds out by the roots. But those herbicides aren't always what they're cracked up to be. Resident New Mexico expert Richard "The Bugman" Fagerland, an integrated pest management specialist and former IPM manager for the city of Santa Fe, shared a recent exchange that illustrates the problems:


When I was driving recently, I saw a fellow spraying weeds. I won't say who it was, but I did contact the organization doing the spraying. I stopped and asked the fellow what he was doing. This is our conversation:

Me: What are you spraying?

Him: I am spraying weeds.

Me.: What are you using?

Him: Roundup. Very good product and safe.

Me: Roundup is listed as cancer causing in California.

Him: We aren't in California.

Me: So Roundup can only cause cancer in some states?

Him: (No answer)

Me: What kinds of weeds are you spraying?

Him: Weeds!

Me: What species? Roundup controls some weeds and just suppresses other species and they are listed on the label whether they are controlled or suppressed.

Him: What does suppressed mean?

Me: When a weed is suppressed, its growth is slowed down, but it isn't killed.

Him: (Silence)

Me: Do you know what kind of weeds you are spraying or not?

Him: I was told they are weeds and we kill them.

Me: The weeds over there are pigweeds and you won't kill them, you will only suppress them. If you want to kill them, pull them out of the ground.

Him: (No answer)

Me: Do you know the Roundup label requires you to wear a long-sleeved shirt and you are wearing a short-sleeved shirt?

Him: It's hot out here.

I just shook my head and walked back to my truck. This fellow had no idea what he was doing. To him and probably many others, weed control is just spraying toxic herbicides on any plants they want. I suggest that if you see anyone spraying weeds in your area, stop and ask them the same kinds of questions and see if they are qualified. I suspect there are more weed sprayers who have no idea of the identity of the weeds they are spraying and what they are actually doing besides polluting the ecosystem.

Want to learn more? Contact Fagerlund at (505) 385-2820, or


Richard Fagerland is an integrated pest management specialist who promotes alternatives to herbicides and pesticides.