BEET, SPINACH, AND CARROT DISEASE. 79 



(318.) From the above account of the turnip disease, 

 we see in the first place that the white turnip is visited 

 with a malady identical in every respect in character with 

 that of the potatoe : the leaf dies, the stalk dies, the root 

 dies, and the two phenomena of gangrene, the dry and 

 wet, are shown. In the second place, the same insect is 

 found upon the plant previously to this change taking 

 place ; and, lastly, the disease appears at those parts of the 

 plant which the creature punctures. Our argument is, 

 therefore, cumulative, for two plants are attacked by the 

 same insect, and this attack is followed by the same 

 disease. 



CHAPTER XIII. 



BEET, SPINACH, AND CARROT DISEASE. 



Beet attacked by the Aphis (319). Mode in which the disease pro- 

 gresses (320 322). Number of insects on a plant (323). An- 

 other species of Aphis (324). Spinach attacked (325). Effects 

 of attack (320). Action of disease (327). Effect of rain on dis- 

 eased plant (328). Carrot subject to the disease (329). Opera- 

 tion of disease upon it (330,331). Disease identical in all plants 

 attacked (332). 



(319.) THERE is another plant of very great importance 

 which this destructive creature infests, and that is the 

 beet-root, including the mangel-wurzel and all its other 

 varieties. The leaves of the beet are frequently to be 

 seen completely loaded with this animal. 



(320.) There is a small field of beet in the Kentroad, 



