Imazamox

Description

Imazamox is registered throughout the world for use in leguminous crops, including soybeans, alfalfa, and edible beans, as well as in imidazolinone-resistant crops (9). A nonionic surfactant or oil adjuvant is required for maximum activity. Imazamox is much more active when applied post-emergent to the weeds compared with pre-emergence application (9). One difference between imazamox and other imidazolinones is the much shorter interval needed before sensitive follow crops can be planted. This difference is due to the more rapid degradation of imazamox in the soil compared with other imidazolinones.

Chemical properties

Off-White Solid

The Uses of Imazamox

Imazamox is an imidazolinone based acetolactate synthase inhibitor that is utilized as a herbicide for weed control.

The Uses of Imazamox

Herbicide.

Definition

ChEBI: 2-(4-isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)-5-(methoxymethyl)nicotinic acid is a pyridinemonocarboxylic acid that is nicotinic acid which is substituted substituted at position 5 by a methoxymethyl group and at position 2 by a 4,5-dihydro-1H-imidazol-2-yl group, that in turn is substituted by isopropyl, methyl, and oxo groups at positions 4, 4, and 5, respectively. It is a pyridinemonocarboxylic acid, an ether, an imidazolone and a member of imidazolines.

Pharmacology

Imazamox kills plants by inhibiting acetolactate synthase (ALS) (I50 = 1 μM), which is the first common enzyme in the biosynthesis of the branched chain amino acids, valine, leucine, and isoleucine. Imazamox is rapidly absorbed through the leaves of plants. Once it enters the plant, imazamox rapidly translocates to the growing points and growth ceases within 1 day after herbicide application, followed by chlorosis and then by necrosis of the growing points. Total plant death will occur within 2 to 3 weeks after treatment.

Metabolism

Plant Metabolism. The selectivity of imazamox is due to differential rates and routes of metabolism in tolerant crops versus susceptible weeds (10). The primary metabolic route is hydroxylation followed by conjugation to glucose. In imidazolinone-resistant crops, the primary mechanism of selectivity is due to an altered acetolactate synthase that is not inhibited by imazamox (11).
Animal Metabolism. Metabolism studies in the rat showed that imazamox is rapidly excreted in the urine. There was no accumulation of imazamox or any of its derivatives in the liver, kidney, muscle, fat, or blood (9).

Toxicity evaluation

Imazamox has shown no mutagenic or genotoxic activity in the Ames assay, mammalian cell gene mutation assay, in vitro chromosome aberration assay, in vitro unscheduled DNA synthesis (URS) assay, or the in vivo dominant lethal assay inmale rats. The acute toxicity and effects on wildlife and soilmicroflora of imazamox are shown in Table 4. This herbicide also has a low potential for bioaccumulation in fish.