23 



Moore and Stone (1909) reported satisfactory results in Wisconsin 

 from the use of a twenty per ct. solution of iron sulfate sprinkled on 

 lawns with a sprinkling can. Plants not killed by the solution were 

 sprinkled with dry iron sulfate soon after the spraying. This appli- 

 cation killed nearly all the remaining plants and apparently caused 

 no injury to the grass. 



In South Dakota, Olive (1909) reported that the results obtained 

 from spraying dandelions with iron sulfate were not as favorable as 

 those reported by other experimenters. However, young plants were 

 killed by one application, while old, large plants required three or 

 more applications. This worker suggested that, possibly, continued 

 use of the spray for two seasons would give better results. 



Selby (1910) mentioned the fact that, in Ohio, tests of iron sulfate 

 show that the first spraying should be made before blossoming of the 

 dandelions, and stated that two or three later sprayings would prob- 

 ably be found advisable. 



At the time of the preparation of this bulletin for publication a 

 survey of the literature reporting recent work on dandelion spraying 

 shows that nearly all investigators are agreed that iron sulfate has 

 considerable value as a dandelion eradicato.r. In Canada, JFyles 

 (1913) sprayed dandelions with a solution of iron sulfate, two -pounds 

 per gallon of water, and reported that after the third application the 

 weeds were still living altho much of their foliage was destroyed. 

 After the third application the spraying was discontinued since the 

 injury to the surrounding grass was greater than to*the weeds. No 

 mention is made of the location of the trials, but jt is inferred that 

 they were made on lawns. A little later, however, Howitt (1913) 

 reported that after six sprayings with a twenty per ct. solution (two 

 pounds per gallon) of iron sulfate applied with a knapsack sprayer to 

 plots of lawn containing 168 square feet the dandelions were reduced 

 in number over ninety per ct. Aside from the black discoloration 

 which immediately followed spraying and disappeared in a few days, 

 no permanent injury was caused to the grass. Jn fact, it -was noted 

 the following spring that the grass on the sprayed plats was greener 

 and more luxuriant than on the unsprayed plat. In 19.13 a one- 

 eighth-acre plat was sprayed six times with a power sprayer using a 

 solution of similar strength. The results obtained were said to be 

 as satisfactory as those secured with a knapsack sprayer. At least 

 ninety per ct. of the dandelions were destroyed. The method is 



