We received a comment on our Research with Pre-Emergence Herbicides, Native Plants blog post and felt it was such a great question, that our response should be shared in it’s own post. Read on…
“Will you also be monitoring effects of herbicide on other native species: arthropods, birds, reptiles, etc.?”
This is an open-end question and I could spend days addressing it. With any pesticide, there are good and bad consequences -you must weigh the benefits with the potential side effects. Herbicides are suppose to impact plants only; however, there are some instances when herbicides can be toxic to plant pathogens or arthropods. Some herbicides can also change the feeding behavior of insects. There has been a lot of talk about the most commonly used herbicide in the world, glyphosate (A.K.A. Roundup), and it’s impact on frogs. But something else is often over looked. Pesticides are made of an “active ingredient” (the poisonous component) along with “other ingredients”. The “other ingredients” are patented secrets and we don’t always know what is included in the herbicide. Pesticide manufacturers want their product to be as effective as possible and they do that by adding adjuvants or surfactants. The role of an adjuvant or surfactant is to increase the penetration of pesticide into the target organism. The idea is the more pesticide the target organism receives, the better it works. Unfortunately, the EPA only requires testing of the “active ingredients” and not all the “other ingredients”. Sometimes these “other ingredients” have detrimental effects on non-target organisms.
Another potential side effect of herbicide is the consequence of removing existing vegetation. Many insect-weed studies have shown that the removal of weeds, by hand or chemical, has an equal effect on insect populations. It is likely the same outcome would be detected for birds or other seed specialists, as well. The big difference is that applying herbicide to 1,000 acres is much easier than hand removing weeds in such a large area.
With all that said, with this experiment, we are looking at only one herbicide and 6 native plant species. We are conducting this research in greenhouse-like conditions that don’t lend well to examining side effects on other organisms. We would have to conduct a targeted study (like this one) that did specific assays examining the effect of an herbicide on tiger beetles.
-CSR’s Senior Scientist, Kelly Tindall
Conservation Seeding & Restoration Inc is not an herbicide spray company. The services we offer do not revolve around chemical applications, but rather the restoration of native plant habitats. When we do use herbicides we treat weeds only so that native grasses and plants can establish themselves and out-compete weeds for water, light, nutrients, and space.