Ethalfluralin is a herbicide. It is a preëmergent dinitroaniline developed from trifluralin, used to control annual grasses and broad-leaved weeds. It was synthesised in 1971, first sold in Turkey in 1975, the United States in 1983.[1] It is used on soybeans, peanuts, potatoes, and as of 2023, is the first conventional herbicide the EPA permits on hemp, as ethalfluralin leaves no residue in the plant.[2] Ethalfluralin is not used domestically.
Ethalfluralin did not leach in soil, and the EPA expects it not to contaminate ground water, though it notes the chemically very similar trifluralin has been found in groundwater. Ethalfluralin is very toxic to fish.
Ethalfluralin works by inhibition of microtubule formation, preventing cell division, and is a Group D / Group K1 / Group 3 herbicide (Australian, Global and numeric HRAC respectively). It is applied at approximately 1 kg/Ha.[3]
In 2024, ethalfluralin was registered in India.[4]
Ethalfluralin is practically non-toxic to birds and mammals, though it causes moderate eye and skin irritation, and skin sensitisation. Subchronic rat and mice studies saw effects to the liver and kidneys, reduced weight gain, and affected enzyme activity. The EPA regards ethalfluralin as a possible carcinogen, due to tumours in chronically exposed rats. Ethalfluralin did not affect the reproductive system or cause strong mutagenisis.[5]
Dietary effect is unlikely as ethalfluralin does not leave residues in plants and doesn't translocate.[2]
Ethalfluralin has been sold as Gilan, Sonalan, Curbit, Sonalen and Edge.