PkKEN N I AL PErrElUiKASS 
9 
necessary, either re-ploAved or hand hoed. This method will prove 
* effective and eliminate perennial peppergrass in small areas. 
I 
Third — Another method is to fence off the patch and turn in 
sheep, which eat it very readily. They will crop the weed close to 
the ground and eventually exhaust its vitality. This is not as effec- 
tive as the hogs and is of doubtful value but it will prevent the 
weeds from forming seeds and in that Avay check somewhat the 
spread. 
' V Fourth The weed, when in small patches, can be killed by com- 
■ pletely covering the ground with some material that shuts out the 
light and prevents the plant from growing through it. Plate III 
i; shows this method as used by Mr. Luther Norland of Sanford. 
Mr. Norland put roofing over the infested spots and extended 
j i it out two feet beyond the weed in all directions. He found it neces- 
sary to lap the roofing and nail it to 1x2 inch strips of lumber in 
order to prevent the weeds from forcing their way between the 
jv strips of roofing. This method will require that the patch be fenced 
t off so that livestock will not walk over the roofing and make holes 
through it, and it is recommended that the field be left covered 
i for two years. Care should be exercised in extending the roofing 
I at least two feet in all directions beyond any visible signs of the 
1 plant as it is able to force its .way a considerable distance hori- 
I zontally. This method is expensive in first cost but if properly pro- 
tected the same roofing can be used later in another place. This 
I is probably the most effective cover that we have seen in use. Almost 
I any other material which can be used would not prevent the shoots 
f| from coming up to the surface through some crack or crevice. 
i In addition to the above methods chemical sprays have been 
A' used effectively in combating many of our worst weeds. Plants 
i 1 of the mustard family are especially susceptible to chemical treat- 
' I ments. Although no spraying experiments have as yet been car- 
I ried out with this species, it is known that an iron sulphate spray 
.? will kill the common peppergrass. The objection to this, however, 
lies in 'the fact that the spray kills only that part of the plant above 
the ground. Consequently one spraying is no more effective than 
jS one cultivation and to make it effective it would be necessary to 
iff spray the patch several times during the season. 
» If salt is used as a control measure a sufficient quantity must be 
% spread over the soil to make it strongly akaline. Thi& will not only 
I* kill the peppergrass but wdll also destroy all other vegetation. If 
