Phytotoxic Substances:  Test Results and Research
Toxicity of Herbicides to Lemna
Phytotoxicity Research


Herbicide Toxicity to Lemna:  Test Results.

Comparative toxicity of 16 herbicides to Lemna minor

Toxicity is based on counting the fronds in the cultures each day.  The EC50 is the concentration of the dissolved test substance that gives a 50% inhibition of growth rate.
 
Chemical Class Herbicide
96-h EC50
(g/L)
95% C.I.
(g/L)

Acetanilide Alachlor
198
80-316
Acetanilide Metolachlor 343 187-872
Triazine Atrazine 153 89-217
Triazine Cyanazine 705 577-834
Triazine Metribuzin 37 22-47
Triazine Simazine 166 102-230
Sulfonylurea Chlorsulfuron 0.7 0.5-0.9
Sulfonylurea Metsulfuron 0.4 0.3-0.5
Pyridine Diquat 18 37-99
Pyridine Paraquat 51 25-77
Thiocarbamate EPTC 7512 1736-13288
Thiocarbamate Triallate >10000
 ----
Benzonitrile Bromoxynil 8065 3783-12348
Benzoic acid Dicamba >100000
 ----
Dinitroaniline Trifluralin 170 10-330
Phenoxy 2,4-D >100000 ----
Data from Fairchild et al. 1997 (see below), cited in Appendix 5: from Michael Davy, Richard Petrie, and Jerry Smrchek, EPA; Ted Kuchnicki and Derek Francois, PMRA,  USEPA Scientific Advisory Panel Briefing "Proposal to update non-target plant toxicity testing under NAFTA."  June 27-29, 2001 http://www.epa.gov/scipoly/sap/2001/june/sap14.pdf

Fairchild, J.F., D.S. Ruessler, P.S. Heverland and A.R. Carlson. 1997. "Comparative Sensitivity of Selenastrum capricornutum and Lemna minor to Sixteen Herbicides." Arch. Environ. Contam. Toxicol., 32: 353-357.



 


Phytotoxicity Research


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Revised:  April 25, 2003