CHAPTER XVII 



CEREAL PESTS WEEDS 



CLOSELY related to the subject of crop cultivation from 

 a practical standpoint is another one of much concern 

 to the cereal grower, that of crop pests. Crop rotations 

 and thorough cultivation check or prevent the ravages 

 of certain insects and fungous diseases, and summer til- 

 lage is practiced largely for the eradication of weeds. 

 Cereal crop pests are of three classes : (1) weeds, (2) in- 

 sects, and (3) parasitic fungi. 



WEEDS 



Any plant growing where it does not belong is a weed, 

 even though it be of value when planted for a purpose. 

 A stalk of corn in a wheat field is as much a weed as a 

 sunflower. Even a volunteer wheat plant in wheat of a 

 different variety is a serious weed. It is impossible in 

 thrashing to separate the volunteer kernels, which injure 

 the quality of the regular wheat for milling and for seed. 

 Weeds are usually more troublesome in small grain crops 

 than in intertilled crops, as the former are not cultivated 

 during growth. 



477. Weeds are injurious to small grains in a number 

 of ways: (1) they occupy space needed by the crop, 

 crowding out the cereal plants and reducing the stand 

 of the latter. (2) They shade and check the growth of 



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