Contents vii 



PAGES 



Setting the plants in the field 92-93 



Cultivation 93-96 



Irrigation 96 



Fertilizers 96-112 



Kinds of fertilizers ... 99 



Function and form of plant-foods 99-103 



Commercial fertilizers ... . . . . 103-105 



Home-mixing of fertilizers 105-107 



What fertilizer to apply 107-108 



Humus . 108-109 



Green-manures .... . . . 109-110 



Other materials as fertilizers ... 110-112 

 Application of fertilizers .... .112 



notation 112-118 



Plant-food . . . ... . 113-114 



Root excretions ... . 114-115 



Mechanical effect on soil 115 



Insect, fungous and weed enemies ... . . 115-116 



Rotation to be used .... 116-118 



Conclusion 119 



CHAPTER VI 



Vabieties .... 120-136 



CHAPTER VII 



Insects Affecting Sweet Potatoes 137-154 



The sweet potato flea-beetle 137-139 



Tortoise beetles 139-143 



The two-striped sweet potato beetle .... 140 



The black-legged tortoise beetle 140-141 



The golden tortoise beetle 141-142 



The mottled tortoise beetle 142 



The argus tortoise beetle ... 142-143 



Control of tortoise beetles 143 



Saw-flies .... 143-145 



Sweet potato weevil 145-154 



Description 147-148 



Life history . . . '. 148-152 



Control 152-154 



CHAPTER VIII 



Diseases of the Sweet Potato . . .... 155-169 



Stem-rot (wilt, blue-stem) . 156-158 



Control of stem-rot 157-158 



