22 



WEED CONTROL: APPLIED BOTANY 



A. S. Crafts 



Among the agricultural practices that have benefited by mechanization and 

 chemicalization, weed control has been one of the last to undergo extensive 

 development. Although much fundamental work had been done prior to 

 1944, introduction of 2,4-D during that year brought about an abrupt increase 

 in activity, and within the last twelve years, weed control has become a 

 multimillion-dollar business. Compared with plant breeding, use of fertilizers, 

 development of insecticides, and mechanization of culture and harvest of 

 crops, however, chemical weed control is still in its infancy. 



When we look into the future, attempting to chart the course of agricul- 

 tural progress, we realize that the bringing in of new arable land, the altering 

 of climate, the improvement of fertilizers, and even the continued breeding 

 of superior crop varieties are all laborious and costly procedures. One of the 

 most promising means for increasing production would seem to be to elimi- 

 nate competition and plant depredation by the use of modern pesticides. 

 Among these, the herbicides seem most promising. 



The growing of plants has always been a struggle. Anyone who has grown 

 up on a farm can remember the perennial job of hoeing weeds in the corn or 

 pulling them from the beets or garden crops. And many a boy has wondered, 

 why grow some plants and destroy others? Why not use the weeds? But 

 agricultural experience has proved the usefulness of crops and the detrimental 

 effects of weed competition. Insects and plant diseases likewise prey on the 

 farmer's crops. Only within relatively recent years have means become avail- 

 able for handling some of these enemies. 



Out of the some quarter of a million plants in the world, only a few are 

 useful as crops, and likewise only a few are weeds. But during the develop- 

 ment of agriculture, by various means of sifting and screening as superior 

 plants have been found and improved, superior weeds seem to have been 

 carried along to compete with them. Furthermore, insects and diseases have 

 sought out the farmer's choice crops and, until recent times, seem to have 



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