196 THE MONTHLY BULLETIN. 



CONTROL. 

 Being an annual plant entirely dependent upon its seed for repro- 

 duction one would expect to find Russian thistle easy to eradicate, but 

 like all noxious weeds, it is easier to keep it out than it is to control 

 it after it has become established. In regions where it is not yet 

 known all avenues of introduction should be watched so that it may 

 be discovered and killed before it is too late. Where it is established, 

 control measures should be put into operation at the proper time 

 fend the work should be thoroughly done. 



There have been several methods recommended by those who have 

 studied the weed, but of them all the surest is crop rotation and the 

 numerous cultivations which it entails, which gives the weeds no oppor- 

 tunity to mature. Since the life of the seed is not more than two 

 years, a rotation of that length of time should completely control 

 the pest. 



Where hay and grain are grown exclusively, the problem becomes 

 more complicated. After the hay is removed from the field, plow- 

 shallow. This will bring the buried seeds near the surface and allow 

 them to germinate, as Russinn thistle is essentially a dry season weed. 

 If the ground is too hard to plow, use a drag or a harrow. With the 

 spring plowing all the small weeds will be killed. The seed for the 

 spring planting should be tested for purity and should be gotten in 

 early in order to give it a good start before the dry season sets in. 

 Grain Avell started will generally hold the thistle in check. 



Burning the stubble after a field lias been headed for grain has been 

 recommended, as the temperature at which death occurs in the seeds of 

 Russian thistle is between 72 degrees and 78 degrees C. But the writer 

 does not favor this method for the following reasons : First, it is a 

 dangerous proceeding, espe'^ially in the dryer regions of California, 

 where foothill fires are so apt to cause great damage ; second, it aids in 

 burning out the soil, a condition which is too often found in California 

 and the Southwestern States; third, organic matter and aeration can 

 be given to the soil by turning this stubble under; fourth, good 

 manure can be added to the soil and good results obtained by turning 

 a large bunch of stock into the field and grazing it thoroughly. Ths 

 thistles that have not been eaten or trampled by the stock can be 

 killed before maturity by fall plowing. 



In 1912, Mr. K. S. Knowlton, county horticultural commissioner of 

 Kern County, began war against the Russian thistle. The district 

 most affected in his county was Tehachapi. Two months ago the State 

 Commissioner of Horticulture visited that region with "Sir. Knowlton, 

 and found the pest entirely under control. This speaks well for the 

 perseverance which the farmers and fruit growers of that region have 

 shown, for it is only by cooperation and persistent thoroughness that 

 such weeds can be suppressed. It also demonstrates that the weed 

 can be controlled and lands once overrun with it redeemed from its 



ravages. 



I want to emphasize the fact that the fight against Russian thistle, 

 as well as against all our noxious weeds, must be characterized by the 

 word thorough. It is useless to attempt a halfway job— time wasted. 

 Every one should cooperate — road supervisors and railroads. No 

 farmer can hope to keep his land clear of any pest when the roadsides 

 and neighboring places continually restock it for him. 



