532 FIELD AND GARDEN PRODUCTS 



with the freshly cut roots or root stocks destroys them for some dis- 

 tance from the point of contact. Crude sulphuric acid is probably 

 the most effective of comparatively inexpensive materials that can 

 be used for this purpose, but its strong corrosive properties render 

 it dangerous to handle. Carbolic acid is less corrosive and nearly 

 as effective. Arsenite of soda, a dangerous poison, is sometimes 

 effective, applied as a spray on the growing weeds. 



3. Roots may be starved to death by preventing any develop- 

 ment of green leaves or other parts above ground. This may be 

 effected by building straw stacks over small patches, by persistent, 

 thorough cultivation in fields, by the use of the hoe or spud in waste 

 places, and by salting the plants and turning on sheep in perma- 

 nent pastures. 



4. The plants may usually be smothered by dense sod-forming 

 grasses or by a crop like hemp, buckwheat, clover, cowpeas, or millet 

 that will exclude the light. 



5. Most roots are readily destroyed by exposing them to the 

 direct action of the sun during the summer drought, or to the direct 

 action of the frost in winter. In. this way plowing, for example, 

 becomes effective. 



6. Any cultivation which merely breaks up the root stocks and 

 leaves them in the ground, especially during wet weather, aids in 

 their distribution and multiplication, and is worse than useless, 

 unless the cultivation is continued so as to prevent any growth 

 above ground. Plowing and fitting corn ground in April and May, 

 and cultivating at intervals until the last of June, then leaving the 

 land uncultivated during the remainder of the season, is one of the 

 best methods that could <be pursued to encourage the growth of 

 couch grass, Johnson grass, and many other perennial weeds. 



Weeds Attracting Special Attention. The influence of the 

 Russian thistle agitation is plainly manifest in the attention given 

 to certain weeds during recent seasons. Nearly one-half of those 

 received at the United States Department of Agriculture with re- 

 quests for naming and information belongs to species which are 

 more or less prickly, and many of them have been mistaken for the 

 Russian thistle. While but few complaints have been received in 

 regard to the older well-known weeds, such as ragweed, dog fennel, 

 and shepherd's purse, it is not to be supposed that these are becom- 

 ing less abundant or less troublesome. People are generally 

 familiar with these common weeds too often so familiar that the 

 weeds have come to be -accepted as a matter of course and a necessary 

 evil. Complaints about Canada thistle, couch grass, and Johnson 

 grass indicate that these weeds, even when well known, can not be 

 disregarded ; but in general it is the new weed coming as an added 

 evil that attracts attention. 



Aside from the Russian thistle, the following ten species of 

 weeds in the order given have received the most notice, according 

 to the reports received at the United States Department of Agricul- 

 ture: 



