60 FARM FRIENDS AND FAR1 



season, it is likely to be less dangerus than if it lives 

 two or more seasons. Like other plats, weeds are com- 

 monly grouped as annual s y living but ne year, biennials, 

 living two years, and perennials^ livinpnany years. The 

 phrase winter annuals is given to thce plants that start 

 their growth in autumn and finish thir development the 

 following spring or summer. 



The remedial measures to be taken aainst weeds depend 

 largely upon the term of life. The anuals live from year 

 to year by means of their seeds. Consquently the preven- 

 tion of seeding by tillage or other mean and the destruction 

 of the seed are the most important geeral measures. It 

 has lately been found that some annua, like the mustards 

 may safely be killed in grain fields by sraying with a weak 

 solution of iron sulphate. The biennds reproduce also 

 by seeds, and are to be treated much a the annuals. The 

 perennials commonly reproduce both b seeds and by root- 

 stocks or other vegetative growths, so tat their destruction 

 is generally more difficult than in the ase of the annuals 

 and biennials. 



The methods that may be employee for the destruction 

 of the roots or rootstocks of perennii weeds have been 

 well summarized by L. H. Dewey in thse words: 



(1) They may be dug up and remove, a remedy that can 

 be practically applied only in small ares. 



(2) They may be killed by apply in Chemicals either to 

 the freshly cut root or at the base of th main stem. Salt, 

 strong brine, coal oil, crude sulphuric acid, and carbolic 

 acid have been successfully used for th; purpose. A few 

 drops of carbolic acid applied at the bae of the main stem 

 with an ordinary machine-oil can is te best method that 

 has been yet devised for killing weeds vith chemicals (ex- 

 cept spraying with sulphate of iron). 



