96 WEEDS OF THE FARM AND GARDEN 



ever, being effectual where a sufficient quantity was used. 

 Stone of Cornell University Experiment Station also re- 

 ported on the successful treatment of certain weeds with 

 copper sulphate, and Moore of Wisconsin reported on the 

 successful treatment of mustard with iron sulphate. 



The above gives an idea of the activity along this line. 

 Perhaps we can do no better than to discuss the different 

 chemicals and their action on weeds separately. 



Copper Sulphate. This well-known fungicide has been 

 found effective for the destruction of certain weeds. At 

 the Iowa station it has been found that it destroyed the 

 leaves of burdock, prickly lettuce, common mustard, prostrate 

 pigweed, and goosefoot. It was ineffectual on the leaves 

 of morning glory, and was only slightly effectual on knotgrass. 

 It did not seriously affect the leaves of the foxtails. The 

 copper sulphate, to be effectual, should be applied ac- 

 cording to the following formula : 12 Ibs. copper sulphate 

 to 52 gallons of water. Spraying should be done in dry 

 weather If it rains immediately after spraying, the 

 spraying should be repeated. Prof. Bolley finds this 

 strength solution is as effective for weeds as 100 pounds 

 of iron sulphate. Professor Howitt of Guelph tells me it 

 is not as effective on mustard as iron sulphate. 



Sodium Chlorid. Salt with some of the weeds experi- 

 mented on by Bolley gave good results, using it at the 

 rate of one-third barrel for fifty-two gallons of water. It 

 is certain, however, that in many of the perennial weeds 

 this will not be effective. It is certainly not effective in 

 the case of the Canada thistle, quack grass, morning 

 glory and milkweed. Salt has been repeatedly recom- 

 mended for Canada thistle, but it is only efficacious where 

 large quantities are used and where cattle are allowed to 

 tramp around or utilize the salt thrown around the roots. 



Salt has long- been recommended to exterminate cer- 

 tain weeds, but Professor Jones of Vermont has shown that 

 while an application of salt may have killed some weeds 



