THE MONTHLY BULLETIN. 471 



MAN AS A WEED DISSEMINATOR. 



So far I have given Nature 's modes of distribution ; those which 

 follow are largely the result of pure carelessness on the part of the 

 farmers and they can be eliminated if we can just make them see the 

 necessity for it. 



I have noted six ways in which man is the direct means of weed 

 spreading: first, by carrying fragments of root stocks and seeds from 

 field to field in threshing machinery, plows, etc. ; second, by scattering 

 manure on field or orchard from stock fed with cheap grade grain and 

 hay which contains many impurities ; third, by permitting the highways, 

 commons and canals to go uncut, thus letting the wind and water 

 transport hundreds of thousands of seeds everywhere ; fourth, by care- 

 less scattering of the straw packing of fruits, vegetables and other com- 

 modities which are transported by rail or steanxship ; fifth, by the con- 

 struction camps along the railroads, and droppings from cars loaded 

 with hay, straw, or grain. The Russian thistle was introduced into 

 California from a railroad construction camp. However, the roads are 

 not wholly responsible for the damage they do. They are merely trans- 

 porting media for impure agricultural crops which farmers ship. In 

 my opinion they have been very good about cleaning their rights of way. 

 Why should a farmer be allowed to ship a load of hay infested with 

 dodder, and possibly Canada thistle seed, any more than he should be 

 allowed to ship a load of potatoes infested with eelworm or Fusarium? 

 I do not believe this should be allowed, and I believe that some day the 

 quarantine service will be extended to include agricultural products 

 infested with all injurious weeds, not merely three or four of the most 

 noxious. 



This brings us to the question of impure seed, which is the sixth and 

 most important means of weed spreading. The impure seed problem 

 is one of vital importance, especially so in California, because we have 

 not yet all the pests of cultivated crops found east of the mountains. 

 There is the Sudan grass question and the possible spread of Johnson 

 gras.s, and there is the constant danger of the advent of Canada thistle, 

 or crab grass in pastures. Furthermore, it is impossible to get the best 

 crops from weed infested fields. Mr. Waite of Imperial County esti- 

 mates the loss as 25 per cent. Not only do the weeds take up space, 

 moisture and nourishment which should go to the crop, but they also 

 reduce the selling value of the grain and the value of the hay as food. 

 The Ohio census placed the loss from dockage on grain in that state at 

 $2,000,000 in 1910. In sowing seed the farmer must necessarily sow a 

 certain amount of weed seed. No seed can be absolutely guaranteed 

 weed free, but he does not have to sow seed which contains five, ten, 

 twenty, and sometimes a higher per cent of impurity when he can have 

 it tested. And right here is a point which shows the importance of being 

 familiar with the principal weed seeds found in agricultural crops. If 

 two samples were tested and one was found to contain six to eight per 

 cent of common dock, clover or trefoil, and the other was found to con- 

 tain one-half to one per cent of Russian thistle, or small seeded dodder, 

 you can readily see that the first would be the more desirable despite the 

 high per cent of weed seed present. If seed testing is undertaken be 



