3,5-dinitro-ortho-cresol [DNC ]. They are not soluble in water but are soluble 

 in oil and may be applied in an oil carrier, or emulsified with water and 

 applied as an enriulsion. The parent connpounds are used for pre-ennergence 

 and nonselective post-emergence weed control. The salts of these connpounds, 

 including sodiunn, ammonium, various annines, and others, are water soluble, 

 and are used for selective pre-emergence and post-emergence weed control 

 in some crops. 



The dinitro compounds are yellow dyes that impart a yellow coloration to 

 clothes and skin. These compounds can be used for weed control without 

 danger if precautions are taken to avoid inhaling the vapors or coming in 

 contact with the spray drift or spray solution. When these materials are 

 used as pre-emergence sprays, severe injury to the crop often results if 

 extrennely high temperatures occur in the Z-v/eek period follov/ing treatment. 



The dinitro compounds are highly toxic (1^0^= 26 to 45 mg./kg.) for rats, 



2. Chloro Substituted Phenols 



These include pentachlorophenol [PCP], which is soluble in oil but not in 

 water, and its sodium salt (sodium pentachlorophenate), which is soluble in 

 water. PCP is used as a fortifying agent in oil sprays for nonselective weed 

 control. PCP in oil and sodium PCP in water are also used for selective 

 pre-emergence weed control in several crops. 



The chlorophenols are of intermediate to high oral toxicity (LD^q = 50 to 

 500 mg./kg. for the various formulations) when fed to rats. 



SUBSTITUTED BENZOIC ACIDS 



2, 3, 6-trichlorobenzoic acid [2, 3,6-TBA] and certain of its isomers are 

 effective herbicides. 2, 3, 6-TBA is translocated in plants and is effective in 

 controlling wild garlic, quackgrass, some species of brush, and a number of 

 perennial broadleaved herbaceous weeds, including bindweed. 



Sodium and amine salts of 2, 3, 6-TBA are sold commercially as a liquid 

 concentrate containing a stated annount of 2, 3, 6-TBA plus a naixture of its 

 isonners. 



Amine salt fornnulations of polychlorobenzoic acids [ PBA] are also avail- 

 able commercially as liquid concentrates. 



CARBAMATES 



The carbamates include isopropyl N-phenylcarbamate [IPC], isopropyl 

 N-( 3- chlor ©phenyl) carbamate [CIPC], 2-chloroallyl diethyldithiocarbamate 

 [CDEC], ethyl N, N-di-n-propylthiolcarbamate [EPTC], and sodium-N- 

 methyldithiocarbamate [SMDC]. They are relatively insoluble in water but 

 are formulated with organic solvents as emulsifiable concentrates. The 

 carbamates forna emulsions ■with ^water and may be applied as either low- or 

 high-gallonage sprays. They are effective as selective dormant post-emergence 



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