354 SUCCESSFUL FARMING 



It sometimes necessitates hand labor, which is most expensive. Also the 

 cost of threshing and cleaning the grain is increased by the presence of 

 weed seeds. 



Market values are lessened by impure grain. Many crops are docked 

 full half their value on account of noxious weed seeds. It is estimated that 

 the State of Minnesota alone suffers a loss annually of over $2,000,000, 

 because of weed seeds in the wheat. 



But the loss does not stop here. Some weeds harbor and encourage 

 harmful fungi and insects. For example, the very common clubroot of 

 cabbage thrives on the various members of the wild mustard family. 

 Stubble overgrown with weeds harbors cut worms, beetles and other insect 

 pests. Mildew, smut and rust are often transferred from friendly weeds 

 to the grain crop. 



Furthermore, livestock and even human beings lose their lives as the 

 result of eating poisonous berries or roots. The water hemlock or cow- 

 bane is fatal to sheep and cattle. The deadly loco-weed on the western 

 plains has caused the death of many horses and cattle. 



How Introduced and Spread. — Weeds are great travelers. They 

 travel by means of the wind and water. They are carried by birds, beasts 

 and human beings. They are disseminated by means of manure, feedstuffs, 

 machinery and grain seeds. 



Such weeds as the thistle, milkweed and the dandelion have downy 

 plumes attached to each seed. The faintest breeze will carry them miles 

 away, where they begin life anew. Members of the dock family have 

 seeds supplied with wings which enable them to float upon the water as 

 well as upon the breeze. Some weed seeds have sharp barbs and stickers 

 by which they attach themselves to the hair of animals and to the clothing 

 of human beings, and are thus carried into new localities. 



When it is known how many thousand seeds one weed-plant produces, 

 it can readily be seen how great a calamity it is to let a weed bloom and go 

 to seed. One thistle head contains enough seeds to start several thousand 

 plants the next year. It is estimated that one wild mustard plant produces 

 10,000 seeds, and one pigweed 115,000 seeds. If only a few of these seeds 

 germinated, the situation would not be alarming, but the chances are that 

 if allowed to seed a very high percentage of them will find opportunity to 

 propagate their kind. 



One of the most prolific sources of weed dissemination is in the buying 

 and sowing of impure seeds. Especially is this true of clover and grass 

 seeds. In an analysis of several samples of commercial seed at one of the 

 experiment stations, one sample of red clover seed was found to contain 

 36,000 weed seeds to the pound. A pound sample of timothy seed contained 

 79,000 weed seeds. 



Care should be taken to procure seeds only from uninfested districts. 

 A farmer should have sufficient knowledge of seeds to enable him to detect 

 impurities. It is a wise precaution to send first for samples of seed under 



