'I'iiK DandkIvIon in Colorado 
13 
ing the season of freest blooming. These little birds usually at¬ 
tack the closed heads, in which the seeds are nearly mature, by re¬ 
moving some of the bracts from one side, after which they pick 
out the seeds and devour them in large numbers. The common 
house finch and the goldfinch consume a great many dandelion 
seeds in the same manner, while even the despised English spar¬ 
row has been occasionally observed at the same good work. 
EXPERIMENTS IN THE ERADICATION AND CONTROL 
OF DANDELIONS IN LAWNS 
During several years experiments have been carried on by the 
writer at the State Agricultural College for the purpose of learn¬ 
ing the most effective and cheapest methods of eradicating and 
controlling the dandelion in lawns. These experiments have in¬ 
cluded the means commonly employed for this purpose, such as 
digging and the use of gasoline, while particular attention has been 
given to the matter of spraying with iron sulphate. 
The following records give the methods employed and the 
results of this series of experiments to the present time: 
Experiments in 1909 
A piece of old lawn, in which the dandelions were uniform 
and so thick as to nearly hide the soil, was selected on the Col¬ 
lege grounds. This was laid off into small plats of equal size and 
treated as follows, using commercial sulphate of iron, or “cop¬ 
peras”, dissolved in water and applied with a bucket spray pump 
so as to thoroughly wet the foliage of every plant: 
Plat No. Strength of Solution Date of Application Re sult October 1 
I.... 
20% 
August 6, August 31, 
September 23 
No dandelions to be 
found 
II.... 
10% 
August 6, August 31, 
September 23 
Less than 1% of 
dandelions present 
III.... 
5% 
August 6, September 23 
About 20% of 
dandelions present 
IV. . . . 
2.5% 
August 6, September 23 
Dandelions injured 
to some extent 
The first spray on Plats i and 11 caused the dandelion leaves 
to turn black and die, but new leaves were pushed out from the 
strongest and oldest plants in a few days. The grass was also 
somewhat blackened at first and throughout the experiment the 
color was a darker green than that on untreated areas. By the 
first of October all dandelions had completely disappeared from 
Plat I, while only two or three were to be found on Plat II. It is 
evident that a 15 per cent solution should be practically as ef¬ 
fective as the 20 per cent for this purpose, and that three appli¬ 
cations, the first as soon as the plants are in full leaf in spring, 
the second in about three weeks and the last in midsummer, should 
