they should not be used under high tennperature conditions for v/eed control 

 in areas adjacent to susceptible plants, such as cotton, tomatoes, grapes, 

 flowers, and ornamentals. These volatile esters are more phytotoxic per 

 pound of acid equivalent than the amine or other salts of 2, 4-D, MCPA, and 

 2,4, 5-T to naost crops, annual weeds, and hard-to-kill •weeds and brush, 

 especially in the more arid regions and under conditions adverse to rapid 

 plant growth. They penetrate leaves rapidly and their effectiveness is not 

 reduced by rain unless it occurs immediately after application. If a range 

 of rates of application is suggested, the esters should be applied at the lower 

 rates and the amine or other salts at the higher rates. 



(b) Relati vely low- volatile ester s . - -This type includes the butoxyethanol, 

 butoxyethoxypropanol, capryl, ethoxyethoxypropanol, isooctyl, propyl- 

 eneglycolbutylether, and other esters known to be low volatile. The low- 

 volatile esters are less hazardous than high-volatile esters in areas adjacent 

 to susceptible crops when tennperatures are 95° F. or less. When temperatures 

 exceed 95° F., the vapors of both the high- and lo'w-volatile esters w^ill cause 

 injury. Even under such high temperatures the low-yolatile esters are less 

 hazardous to adjacent susceptible crops. 



2,4-DlCHL,OROPHENOXYETHYL SULFATE [sesone] 



This herbicide is fornnulated as the sodium salt and is a white crystalline 

 powder that is soluble in water. When applied to moist soils, sesone is 

 converted into a herbicide with properties similar to 2, 4-D. It is effective 

 as a pre -emergence herbicide for w^eed control in a number of crops. Unlike 

 2, 4-D, however, sesone possesses little or no phytotoxicity as a foliage 

 spray on most plants, Sesone, therefore, is much safer than 2, 4-D as a 

 pre-emergence treatment in areas ^vhere 2, 4-D spray drift, or vapors of 

 esters of 2, 4-D are hazardous to susceptible crops, such as cotton, grapes, 

 tomatoes, and sugar beets. Sesone is not effective as a post-emergence 

 foliage spray; therefore it must be applied to the soil before ennergence of 

 the ^veeds to give effective control. It has been effective as a post-planting 

 spray for w^eed control in strawberries when applied before emergence of 

 the weeds. The herbicide has been erratic in performance during periods 

 of inadequate soil moisture. 



Sesone is of relatively low toxicity (LD5o= 730 to 1,400 mg./kg.) for rats. 



SUBSTITUTED PHENOLS 



The dinitro alkyl phenols and chloro substituted phenols have been used 

 widely as contact selective and nonselective post-emergence herbicides. 

 They also have been used for selective pre-emergence weed control in a 

 number of large-seeded crops, including peanuts, soybeans, lima beans, 

 snapbeans, and cotton. The substituted phenols consist mainly of two types. 



1. Dinitro Compounds 



These include the parent compounds 4, 6-dinitro-ortho- secondary butyl- 

 phenol [DNBP], 4, 6-dinitro-ortho- secondary amylphenol [DNAP], and 



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