118 



CHAPTER XXII. ; 



ARTIFICIAL REMEDIES FOR THE POTATOE DISEASE. 



Division of subject (464). Destruction of Aphis considered : by 

 human means (465) ; by tobacco (466). Effects of water, thunder- 

 storm, on Aphis rosae (467) ; on vastator ("468). Burning infected 

 leaves (469). Effect of leaf-burning in beet (470). Quicklime 

 (471). Ducks and soft-billed birds (472). Coccinellae and ich- 

 neumons (473). Wheat (474). Early ripening (475). Early 

 potatoes (476). Autumn planting (477). Recapitulation (478). 

 Contagion (479). Burning infected haulms (480). Isolation of 

 crops (481). Means to be adopted over large districts (482). 

 Same means for all crops (483). Propagation from healthy sets 

 (484). Generation of fibre (485). Means of inducing this (486). 

 Sets (487). Varieties resembling the wild potatoe (488). 

 Planting in sand or peat (489). Dryness, warmth, and light 

 (490). Propagation of the young stalks (491, 492). Requisites 

 for healthy propagation (493, 494). Diminished starch (495). 

 Starch cells (495). Remedies which have been proposed (497). 

 Drying (498). Cold and dryness (499). Review (500). 



(464.) THE artificial remedies to be adopted to lessen the 

 potatoe malady may be divided into four great classes. 

 One class comprises those means which we should take to 

 lessen the numbers of the insect, and thus strike at the root 

 of the cause. The second class contains the treatment to 

 be pursued for stopping the contagion. The third class 

 comprises those remedies which are destined to prevent the 

 continuance of the disease in the infected plant; and, 

 lastly, we have to consider a fourth class, where we desire 

 to lessen the baneful agency of the malady when it has 

 actually occurred. 



