Warfarin, red squill, zinc phosphide, and ANTU are generally recomoiended for 

 use by the public. They are usually available commercially and are the ones with which 

 the untrained individual is the least likely to experience difficulties. Commercial 

 preparations of prepared baits containing arsenic, phosphorus, and strychnine are 

 commonly sold on the retail market; their use is best restricted to indoor protected 

 stations where accidental poisoning hazards are minimized. Barium carbonate, once 

 rather widely recommended, is rarely used today as it is too weak to be effective. 

 Thallium sulfate is very dangerous and quite costly; except for some grain-treated 

 baits used for mouse control, it is used almost exclusively by professional operators. 

 Sodium fluoroacetate , or Compound 1080, is not available to the general public because ' 

 of its extreme toxicity. 



Of the first four materials mentioned above, red squill is considered among the least 

 hazardous poisons for the untrained individual to handle. Its emetic factor offers 

 protection to animals capable of vomiting. However, since some farm animals do not 

 vomit, care must be taken to prevent their contact with the material. Red squill is a 

 relatively distasteful mild poison, hence its shortcoming; so nauch must be incorporated 

 into the bait that some rats object to the taste and soon learn to refuse it. ANTU, if used 

 properly, will give good results against Norway rats, but is ineffective against roof i ats 

 and, like squill, is of no value against house mice. The strong reluctance of rats to 

 accept a second dose as well as the marked tolerance which is developed have combined 

 with the accidental hazards to reduce sharply the use of ANTU throughout the country. 

 It should not be used more often than at four month intervals to obtain best results and 

 baits containing the material should not be left in place for more than three or four days. 



Zinc phosphide is not widely used, partly because it is not readily available and 

 partly because of its high toxicity and strong odor. However, this offensive odor and 

 unattractive color provide a safety factor. Most domestic animals will not touch baits 

 prepared with it, but rodents seem to like the pungent odor of phosphorus compounds. 

 Furthermore, all species of rats and mice, both domestic and native, readily accept 

 zinc phosphide treated baits. The net result is that of the three poisons thus far 

 mentioned, it is the most likely to produce universally satisfactory results. 



A greater degree of protection to other animals, when either zinc phosphide or 

 ANTU is used, may be obtained by incorporating tartar emetic (antimony and potasium 

 tartrate) in the bait mixture. Approximately equal amounts with ANTU or three parts 

 of tartar emetic to eight parts of zinc phosphide provide about the same relative degree 

 of protection to other animals as may be expected in the case of red squill. 



Warfarin, outstanding in its value to the general public, is the most recent material 

 to be added to the list. It incorporates a radically different principle of control by poisons. 

 An anti-coagulant, this chemical must be taken daily over a period of several days as 

 opposed to the single dose compounds. The aninnals, apparently not associating the 

 cumulative effect of internal hemorrhaging with their food supply, return to feed on 

 warfarin treated baits again and again. Thus the problem of bait shyness is largely 

 overcome. At the same time, hazards to other animals from single accidental feedings 

 is greatly reduced. Since repeated feedings are required, permanent covered bait 

 stations provide an excellent technique for exposure; relatively large supplies of bait 

 obviate the necessity for daily care. Warfarin possesses the added advantage of being 

 effective against all species of rats and mice. 



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