14 VERMONT AGRICULTURAL REPORT. 



and convenience of application, are the things to determine 

 choice among the various compounds available. Without at- 

 tempting to list all of these, we include those whose worth has 

 been best established by trial. 



Salt. (Sodium chloride). This is probably more commonly 

 used than any other compound, chiefly because of cheapness and 

 handiness. Its action depends almost wholly upon the with- 

 drawal and retention of moisture from the plant, therefore it 

 should be applied dry or in strong solution, and it is most effect- 

 ive in hot, dry weather. Salt can be used in any weed killing 

 operation, but is most valuable on roadways, etc., and for certain 

 lawn weeds. 



Blue vitriol. (Copper sulphate). This is more powerful 

 in herbicidal action than salt, but its cost prohibits its general 

 use. For most purposes it is best used in solution, from 2 to 

 lo percent being efficient. It is often used on gravel walks, etc., 

 but salt will generally be found cheaper and arsenical poisons 

 more efficient. Its chief value is against charlock, as noted below. 

 Kerosene, Petrol en in oils. Kerosene and other coal oil prod- 

 ucts will kill plants. On account of handiness it is frequently 

 used, but it is weak in efficiency and relatively more costly than 

 any other chemical here listed. A pint of crude carbolic acid will 

 do much better service than two gallons of kerosene, and cost 

 much less. Gasoline is more effective than kerosene in some 

 cases. When crude petroleum is available at a very low price it 

 is commended. 



Carbolic acid. This is one of the quickest and most valua- 

 ble herbicides. The crude acid is relatively cheap. It is not 

 quite equal to the arsenical poisons for penetrating the soil or 

 in lasting effects but is often preferable on- account of cost or 

 convenience. It does not corrode metals, hence may be applied 

 with any can or pump. An effective method is to squirt the 

 strong acid from an ordinary oil can upon the roots or crown of 

 individual weeds. If to be sprayed or sprinkled broadcast on 

 the foliage or ground it should be diluted with from 15 to 30 

 parts of water, and this mixture agitated frequently during use. 

 Sulfuric acid. (Oil of vitriol). This is, of course, de- 

 structive to everything it touches. It can be applied in the crown 

 or about the roots of coarse or especially hardy plants, providing 

 one is willing to kill the adjacent vegetation also. In general, 

 carbolic acid will be preferred, partly because sulfuric acid can 

 be handled only in glass vessels. 



Caustic soda. A strong solution of this makes a cheap and 

 effective herbicide, commended especially for pouring on soil 

 where it is desired to destroy poison ivy or other deep rooted 



