OUTLINE OF CHAPTER FIVE 



CROP ENEMIES AND FRIENDS 



tfeeds: 



Some annuals: 



Charlock, chess, corncockle, dog fennel, pigeon grass, cocklebur, 



horse weed, wild lettuce, ragweed, Russian thistle 

 Some biennials : 



Bull thistle, burdock, wild carrot 

 Some perennials: 



Bind weed, Canada thistle, dandelion, horse nettle, nut grass, 



oxeye daisy, rib grass, sorrel, wild onion 

 Destroyed by 



Clean, cultivated crops 

 Preventing the maturing of seed 

 Smother crops 

 Fungous Diseases: 



Some characteristics of fungi : 

 Feed on other plants and animals 

 Lack chlorophyl or leaf green 

 Reproduce by spores instead of seeds 

 Some fungous diseases: 



Blight, black knot, mildew, mold, rot, rust, scab, smut, wilt 

 How to protect crops : 

 Destroy fungi, 



On soil, by burning diseased plants 

 In soil, by depriving them of host plants 

 Plant and breed resistant varieties 

 Store fruit and grain when they are dry 

 Remove spores from infested seed 

 Destroy spores of fungi by 

 Dust spray of flowers of sulphur 

 Liquid spray of copper sulphate, lime, and water (Bordeaux 



mixture) 



189 



