Preemergent herbicides

Trifluralin is a common preëmergent selective herbicide, a dinitroaniline. With about used in the United States in 2001, and in 2012, it is one of the most widely used herbicides. Trifluralin is also used in Australia, New Zealand, Iran, India, Brazil and previously in the EU. Introduced in 1964, Trifluralin was the first organofluorine compound used as an agrochemical.

Pendimethalin is a selective herbicide of the dinitroaniline class used preëmergently and postemergently to control annual grasses and certain broadleaf weeds. It inhibits cell division and cell elongation. Pendimethalin is approved in Europe, North America, South America, Africa, Asia and Oceania for different crops including cereals (wheat, barley, rye, triticale), corn, soybeans, rice, potato, legumes, fruits, vegetables, and nuts, plus lawns and ornamental plants.

Metolachlor is an organic compound that is widely used as an herbicide. It is a derivative of aniline and is a member of the chloroacetanilide family of herbicides. It is highly effective toward grasses.

Benfluralin (or Benefin) is a herbicide of the dinitroaniline class. The mechanism of action of benfluralin involves pre-emergent inhibition of mitosis, root and shoot development, same as trifluralin, from which benfluralin was developed in 1963. thumb|Shows states where benefin (as Balan DF) is registered (Green) or not (Red). Not shown: Hawaii, where it is registered.

MCPB, 2,4-MCPB, 4-(4-chloro-o-tolyloxy)butyric acid (IUPAC), or 4-(4-chloro-2-methylphenoxy)butanoic acid (CAS) is a selective phenoxybutyric herbicide. In the United States it is registered for use on pea crops before flowering, for post-emergence control of broadleaf annual and perennial weeds including Canadian thistle, buttercup, mustard, purslane, ragweed, common lambsquarters, pigweed, smartweed, sowthistle, and morning glory. It has low to moderate acute toxicity, with kidney and liver effects as the main hazard concerns.

Oryzalin is a herbicide of the dinitroaniline class. It acts through the disruption (depolymerization) of microtubules, thus blocking anisotropic growth of plant cells. It can also be used to induce polyploidy in plants as an alternative to colchicine.

Isoxaben (N-[3-(1-ethyl-1-methylpropyl)-1,2-oxazol-5-yl]-2,6-dimethoxybenzamide) is an herbicide from the benzamide and isoxazole family.

Dithiopyr is a preemergent herbicide for crabgrass control in turf and ornamental grasses. It is effective on 45 grassy and broadleaf weeds. Dithiopyr inhibits root growth of susceptible weeds as well as turf grass and thus should be used only on established turf with a well-developed root system. Its duration of efficacy is approximately 4 months, so lawns should not be reseeded during this time frame following application of the chemical. Dithiopyr acts primarily as a preemergent herbicide but can also be used in early postemergent control of crabgrass.

chemical compound

Prosulfocarb is a preëmergent herbicide used agriculturally in Australia, the EU, Japan, New Zealand, (since 2020), Morocco and Iran, for control of annual ryegrass and toad rush in wheat and barley crops. It was introduced to the EU in 1988 and is rapidly growing in use, with sales increasing by over 500% in France since 2008.

Butralin is a preëmergent herbicide used to control suckers on tobacco in the United States, Australia, Mozambique and, for food crops also, China. It is a dinitroaniline, first registered in the US in 1976. It was used in the EU until a ban in 2009 due to its ecotoxicity.

chemical compound

Tri-allate or triallate is a selective preëmergent thiocarbamate herbicide, used to control wild oats and sundry grasses and broadleaf weeds, often co-applied with trifluralin, which is much weaker against wild oats than tri-allate. Residual control can be expected for 6 to 8 weeks. It is used in Australia, India and the United States. It was first registered in 1961.