Effects of roundup

Asked September 2, 2014, 2:20 PM EDT

Does round up kill worms, ladybugs and other microorganisms that are helpful in a garden? Seems most of the neighbors use it without a thought to that.

Denver County Colorado

1 Response

Before any pesticide/herbicide (including glyphosate, aka "Roundup") is registered for use in the United States, the active ingredient must undergo years of required studies to investigate the potential for negative/toxic effects on humans, wildlife and other non-target organisms. These tests are conducted on representative small mammals, birds, fish, invertebrates (including earthworms), honey bees, and soil microbes, to name a few. The evidence from these studies indicates that glyphosate will not cause unreasonable adverse effects to wildlife and other non-target organisms when used according to label directions. In 1993, when glyphosate was reregistered in the U.S., the Environmental Protection Agency (EPA) stated: “Based on current data, EPA has determined that the effects of glyphosate on birds, mammals, fish and invertebrates are minimal” (U.S. EPA 1993). In addition to studies required by the U.S. EPA and other regulatory bodies, many other studies have been conducted with glyphosate products during more than 30 years of use. The weight of evidence from these studies supports the conclusion from regulatory studies that no unreasonable adverse effects are predicted from the normal use of glyphosate (Sullivan and Sullivan, 2000).

Numerous studies support the conclusion that normal use of glyphosate will not increase earthworm mortality. A comprehensive review of the effects of agricultural chemicals on earthworms reviewed the effects of glyphosate on earthworms (Edwards and Bohlen 1996). Glyphosate's effect was ranked as zero on a scale of zero (relatively non-toxic) to 4 (extremely toxic). Monsanto and several independent researchers have conducted studies in which no adverse
effects were observed when earthworms were exposed to glyphosate residues in soil at rates equal to or greater than labeled rates (Giesy et al., 2000). In field studies, it has been demonstrated that earthworms thrive under conservation-tillage cropping practices, in which glyphosate herbicide is often used (Giesy et al., 2000).

In a screening assay in which 18 different beneficial insects were exposed to
the original Roundup1 formulation on a synthetic surface, the formulation was found to be “harmless” to 13 species, “slightly harmful” to four species and “moderately harmful” to one species (carabid beetle) (Hassan et al. 1988). A subsequent semi-field test with a similar glyphosate formulation indicated that even when carabid beetles were directly oversprayed at the maximum use rate, no mortality was observed.

Hiqh quality, peer-reviewed research suggests that, when used according to all label instructions, glyphosate should pose no hazard to earthworms, insects (including honey bees) and soil microorganisms.

Citations for the above have been included below for your reference.


Edwards CA, Bohlen PJ (1996) Biology and ecology of earthworms. Ed. 3. Chapman & Hall Ltd. London.

Giesy JP, Dobson S, Solomon KR (2000) Ecotoxicological risk assessment for Roundup herbicide. Reviews of Environmental Contamination and Toxicology 167: 35-120.

Hassan SA, Bigler F, Bogenschütz H, Boller E, Brun J, Chiverton P, Edwards P, Mansour F, Naton E, Oomen PA, Overmeer PJ, Polgar L, Rieckmann W, Samsøe-Petersen L, Stäubli A, Sterk G, Tavares
K, Tuset JJ, Viggiani G, Vivas AG (1988) Results of the fourth joint pesticide testing programme carried out by the IOBC/WPRS-Working Group “Pesticides and Beneficial Organsisms”. J Appl. Entomol 105: 321-329.

Sullivan DS, Sullivan TP (2000) Non-target impacts of the herbicide glyphosate: A compendium of references and abstracts. 5th Edition. Applied Mammal Research Institute, Summerland, British Columbia, Canada.

U.S. EPA (1993) Reregistration Eligibility Decision: Glyphosate. U.S. Environmental Protection Agency.