Whorlbd Milkweed 
31 
Doubled disced June 26. 
Double disced July 8. 
Plowed with tractor 8 inches to 10 inches deep July 23. 
Double disced August 26. 
Double disced September 20. 
Double disced October 15. 
The principle followed in this treatment was to keep the 
plant from having any green leaves during the season; at no 
time was the milkweed allowed to form any green leaves. As 
soon as a very few showed through the surface the plot was 
double disced. The persistence with which the roots continued to 
send up stalks thru the soil was remarkable. It must be remem- 
bered that no rains fell during the period from June 1 to Septem- 
ber 1, and that by the latter date the upper 8 inches of soil was 
as dry and as porous as an ash heap. Every bit of milkweed in 
this upper layer was dried up and dead but the roots below the 
furrow slice continued to send shoots to the top of the soil thru 
the dry dirt until fall. Figure 23 is a picture taken of some of 
these shoots. In most cases these roots were about the size of or- 
dinary binding twine or smaller, and yet enough shoots were sent 
up to make the stand as thick as it was originally. 
From May 16 to May 20, 1919, this plot was double disced 
and harrowed. On May 20 part of the plot was planted to pota- 
toes and part to corn. These two crops were treated as follows 
during the season. 
Hoed June 10. 
Hoed June 26. 
Cultivated three times over July 25. 
Cultivated August 10. 
The crop was given the treatment of an ordinary farm crop, 
with the exception that a little more care was given. 
The rainfall during the 1919 season was considerably greater 
than in 1918, but the corn and potatoes were not irrigated. De- 
spite this treatment the milkweed was thicker in 1919 than it 
had been at the beginning of the experiment in 1918. The pota- 
to and corn crop were not in any way held back by the milkweed. 
In fact, due to the summer fallow the previous year, the crops 
were very good, as shown in Figure 24. The experiment was a 
good demonstration, proving conclusively that thorough work, 
begun early and continued thruout the season, and followed the 
next year by a hoed crop, is inefficient as a means of eradicating 
milkweed. 
