1913.1 PUBLIC DOCUMENT — No. 31. 35 



WEED EXTERMINATION: 



G. E. STOKE. 



In recent years a groat deal has been done along tlie lines of 

 weed extermination, and many different methods have been ex- 

 perimented with and some of them adopted. There arc several 

 proprietary articles and meclianical devices on the market pnr- 

 ])orting to solve some of the phases of the weed question, but 

 ni'ost of them are rather expensive when used on a large scale. 

 When one needs only a small amount of wccdicide, however, it 

 is better to buy the easily procured proprietary article than to 

 bother with the crude material, which is often hard to ol)tain. 



Sulfate of iron has proved valuable in the west for the ex- 

 termination of such tender plants as mustard and others when 

 used as a spray in grain fields, and it can also be used for 

 hilling dandelions in lawns. It is inexpensive Avhen bought in 

 bulk, although the proprietary article, consisting of pulverized 

 sulfate of iron mixed with nitrate of soda and sand and put out 

 in expensive containers, is not so cheap. Arsenate of soda, 

 which can be bought in bulk or as a commercial article, and 

 similar compounds are also used as weed killers. 



Of the several mechanical devices used for weed extermina- 

 tion, some are designed to pull up the weeds and others to kill 

 them by injecting poisonous chemicals into the roots, while still 

 otlicrs do the work by burning. Even electricity has been tried, 

 but with rather unsatisfactory results, since considerable cur- 

 rent is required to kill even small plants. Salt, copper sulfate, 

 carbolic acid, nitrate of soda and many other materials have 

 been used as Aveed killers, and undoubtedly in the future 

 cheaper and more efficient methods will be found. 



Ai?sr:is"ATE of Soda. 

 Arsenical compounds appear to be the most poisonous to 

 weeds. Of these, arsenate or arsenite of soda is usually em- 



