REPORT OF THE SOCIETY 77 



The advantage of spraying to kill this plant is that it is not necessary to 

 come into contact' with the leaves as would be necessary or unavoidable if an 

 attempt were made to cut it. 



Wild Carrot (Daucus Carota L.). — Spraying with a 10% solution of sulphuric 

 acid applied at the rate of 89 to 134 gallons per acre will check it. 



Spreading Dogbane {Apocynum androsaemifoliiim L.). — When growing on 

 waste ground it may be got rid of by spraying with a 5% or stronger solution of 

 caustic soda. 



Corn Gromivell {Lithospermum arvense L.). — Spray with 20% iron sulphate 

 when the first blossoms appear. 



Heal-all {Prunella vulgaris L.). — Repeated spraying with 20%, iron sulphate 

 will kill it. 



Dandelion {Leontodon taraxacum L.). There is no doubt whatever that 

 dandelions growing on a lawn can be checked by spraying with a 20 per cent 

 solution of iron sulphate, but the length of time required to kill the dandelion 

 roots absolutely, seems never to have been finally settled. This chemical kills 

 at the same time white clover, but does not appear to do any permanent harm to 

 grass unless in exceptional cases. 



Experiments carried out at Guelph, Ont., during three years showed that 90% 

 of the dandelions on a lawn were destroyed by spraying six times during the 

 season. Twent\' gallons were used to spray one-eighth of .an acre. The results 

 obtained at Geneva, New York State, were not so satisfactory. After spraying a 

 plot six times in the season and again six times in the following season, there were 

 still alive 1085 dandelions on 1000 square feet; one and a half pounds of iron sul- 

 phate per gallon of water were used for the first sprayings and two pounds per 

 gallon of water during the second season. Further spra^dng in the second season 

 had to be discontinued owing to injury to the grass. 



Clothur {Xanthium canadense Mill.). It may be killed when three to eight 

 inches high, by spraying with 20% iron sulphate. 



Greater Ragweed {Ambrosia trifida L.) This weed can be kept from forming 

 seeds by spraying with a 20% solution of iron sulphate or 1}^ pounds of sodium 

 arsenite in 52 gallons of water. Spraying should be done when the grain is 8 to 

 10 inches high. 



Common salt, 130 pounds in 52 gallons of water, is also a good spray for this 

 plant. 



White Top {Erigeron anniius L.) Iron sulphate of the usual strength (20%) 

 appears promising. 



