108 POTATOE GANGRENE AND OTHER DISEASES. 



destruction by a little insect, yet curiously enough our 

 hope of preservation from this calamity is in a great 

 measure dependent upon the operations of another insect 

 even more minute. 



CHAPTER XIX. 



RELATION OF THE GANGRENE TO OTHER DISEASES OF THE 

 POTATOE. 



The curl (430, 431). Rollins' description; varieties of curl (432 

 434). Putsche and Vertuch's description (435). Curl probably 

 identical with present disease (436). Curl from attack of vastator 

 (437). The rust (438). 



(430.) THE potatoe is affected with other diseases besides 

 the gangrene, such as the curl, &c. The curl was so 

 extremely prevalent some years ago, that the Society of 

 Arts awarded a premium for the best remedy. 



(431.) The curl, though very common at the commence- 

 ment of the nineteenth century, has departed for many 

 years, so that now we can only know the disease by re- 

 port. 



(432.) Hollins describes the half-curl, the curl, and the 

 corrupted. " The half-curled plants have leaves some- 

 what long, and curl only in a moderate degree ; they pro- 

 duce a tolerable crop if the summer be not very dry; but 

 if otherwise, the produce will be small and watery." 



(433.) " The completely curled potatoe plants are seldom 

 more than six or seven inches high. They soon ripen and 



