Areas frequented by livestock should not be treated with sodium arsenite 

 because of hazard of poisoning: Sodium arsenite is highly toxic for mammals 

 (LD50 = 10 to 50 mg./kg.) when administered orally. 



2-CHLORO-N,N-DIALLYLACETAMIDE (CDAA) 



CDAA is formulated as an emulsifiable concentrate. It has shown 

 promise for pre-emergence control of weed grasses in soybeans, corn, 

 and in certain other crops. CDAA is less effective on broadleaved weeds 

 than on grasses. It often causes some temporary stunting of broadleaved 

 weeds which opens the way to more effective control by timely cultiva- 

 tion. CDAA may cause serious irritation to the eyes. This hazard can be 

 reduced by wearing goggles and rubber gloves during application. 



DICHLORAL UREA (DCU) 



DCU is used for pre-emergence weed control in sugar beets. It is more 

 effective for control of grasses than for broadleaved weeds. It is low in 

 solubility and is formulated as a wettable powder. 



DCU is claimed to have low oral toxicity. 



METHYL BROMIDE 



Methyl bromide applied at heavy rates as a volatile temporary soil 

 sterilant will kill most weed seeds and plants. It has a boiling point of 

 38° F., and is sold in sealed cans as a liquid under pressure. When released 

 at 68° F., it becomes a gas 3.2 times heavier than air. The gas must be 

 released under an airtight cover for use as a soil sterilant. Confining the 

 gas under an airtight cover for 24 hours is usually sufficient for weed 

 control if soil in the treated areais moist and has been loosened to aid gas 

 penetration. It is safe to plant crops 2 to 3 days after the airtight cover is 

 removed. Methyl bromide gas is poisonous to man and animals . Effects of 

 exposures within a 24-hour period are cumulative. Skin contact can produce 

 severe burns. The gas is colorless with a slight, sweetish odor, and warn- 

 ing traces of other gases, such as chloropicrin, are sometimes added. 



Methyl bromide is relatively toxic, having the power to be absorbed by 

 the skin as well as by inhalation. 



2,3-DICHLORO-l,4-NAPHTHOQUINONE (Dichlone) 



Dichlone is available as a dry, wettable powder that wets and disperses 

 readily in water. It is used for control of blue-green and green algae in 

 lakes and ponds. It mixes well with oil, is chemically stable, and, as an 

 algicide, remains active in water with a pH up to 9 or 10. 



Dichlone is relatively low in oral toxicity (LD5Q = 1,500 mg./kg.) for 

 rats. 



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