WiioRLEi) Milkweed 
33 
Fig-. 24 — Corn crop on Plot IV, August 1919. Note the 
small milkweed in foreground. 
ches deep was dug along the full length of the patch on the side 
away from the ditch. This trench was then ‘‘moved across'’ the 
patch and all the roots thrown out, (Fig. 25). 
On August 23, it was estimated that 3 per cent, of the milk- 
weed was showing up, and the patch was thoroughly regrubbed. 
During the season of 1919, twelve spindling shoots of milkweed 
came up in the patch. The plot was covered with a heavy stand 
of horsemint which effectually shaded the ground and held the 
milkweed back. In this case over 99 per cent, of the milkweed 
was killed. It is noticeable that in this ca^e work was not begun 
unitl later in the season than on any previous plot, and that the 
ground was immediately taken by a plant that effectually shaded 
the Soil. It has been noticeable in all the eradication work for 
this plant that work begun early in the season is ineffective. 
The closer it was to seeding time when work was begun the 
larger was the percentage of milkweed killed for the effort ex- 
pended. 
