Clomazone is an
agricultural
Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
herbicide
Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...
, and has been the active ingredient of products named "Command" and "Commence". The molecule consists of a 2-chlorobenzyl group bound to a N-O heterocycle called isoxazolidinone. It is a white solid.
Clomazone was first registered by the USEPA on March 8, 1993, and was commercialized by FMC Corporation. It is used for broadleaf weed control in several crops, including soybeans, peas, maize, oilseed rape, sugar cane, cassava, pumpkins and tobacco. It may be applied pre-emergence of incorporated before planting the crop. Clomazone is relatively volatile (vapor pressure is 19.2 mPa) and vapors induce striking visual symptoms on non-target sensitive plants. Clomazone undergoes biological degradation, exhibiting a soil
half life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...
of one to four months. Adsorption of the herbicide to soil solids slows degradation and volatilization. Encapsulation helps reduce volatility and therefore reduces off-target damage to sensitive plants.
Clomazone suppresses the
biosynthesis
Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. ...
of
chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...
and other plant pigments.
[Gara, Pedro M. David; Rosso, Janina A.; Martin, Marcela V.; Bosio, Gabriela N.; Gonzalez, Monica C.; Martire, Daniel O. "Characterization of humic substances and their role in photochemical processes of environmental interest" Trends in Photochemistry & Photobiology 2011, vol. 13, pages 51-70.]
References
{{Herbicides
Herbicides
Chloroarenes
Isoxazolidinones