Swep or MCC is a carbamate herbicide discovered in the 1960s, formerly used to control annual weeds and grasses in rice, potatoes, cotton, corn, peas, peanuts, and sorghum, and is no longer used in the US Notably, swep must be applied at high rates per acre compared to other herbicides, 3.75-5.62 kg/Ha (3.35-5.01 lbs/ac.).
Mechanism of action Swep interferes with cell division and growth.
Environmental behaviour Swep is relatively volatile, with a vapour pressure of 187 mPa, so swep can be lost to the atmosphere. In a laboratory soil degradation test, the amount of swep in soil halved in 21 days. Degradation is by microbial breakdown, not by chemical means. 3,4-Dichloroaniline (DCA) is swep's primary metabolite, roughly one part in six of which is further transformed to 3,3',4,4'-tetrachloroazobenzene (TCAB). DCA can be broken down (mineralised) by many microbes, including strains of variovorax, sphingomonas and achromobacter. A "consortium" of a couple of bacteria strains can convert swep to DCA and then break down the 3,4-DCA. DCA is an intermediate, and does not accumulate in meaningful quantities are swep decomposes.
Uses Swep is usually formulated as an emulsifiable concentrate (EC). Swep can control grasses, broadleaf weeds, and sedges, including barnyard grass, purslane, chenopodium and trifoliate grass. It is used on cereals and vegetables including leek, green onion and garlic.
References
External links Swep in the Pesticide Properties DataBase (PPDB)