1 1 2 Cultivation of Arable Land. Potatoes. Difeafts ofCu-rt. 



numerous minute animalculne, but that the general caufe is in the feed itfelf 



being confumed. 



On this account it is, therefore, that the difeafe abounds more in potatoe 



crops in the rich foils in the vicinity of cities, and in that of well-manured gar 



dens ; as in fuch, infects are the mod predominant. 



Jt is alfo fufpected that fome forts of potatoes are more liable to be attacked 



by animals of the above kinds than others, as they have fcarcely ever been ob- 



ferved to meddle with the yam. Such varieties of the potatoe as have been 



brought from backward diftricts, and which have not bem perfectly riprned, 



are likewife, it is thought, feldom reliihed by thefe infedts. But fuch as have 



been made in any degree fweet and mellow by the action of froft, are fure to 



be attacked by them.* 



As the general experience of cultivators has fully (hewn that the crops of fuch 



potatoe fets as have been brought from high cold climates, where the potatoe 

 fcarcely ever arrives at that (late of perfect maturity in which feed is produced, 



.is rarely if ever affected with the curl for the firft year, this opinion is rendered 



extremely probable. -( 



And the trials of a very extenfive cultivator not only clearly demonftrated that 

 there was not the leaft difference in refpect to the production of this difeafe, 

 whether whole potatoes, large cuttings, fmall cuttings, or the eyes merely, were 

 employed ; but that fuch potatoes as were brought from the late districts about 

 Dumfries in Scotland, were never known to afford curled crops the firft year. 

 The cultivator is, however, cautioned againft ufing them in the third year, 

 as, however rich the land or good the manure may be, they will almofl all be 

 affected with the curl if fet in the fame foil.j 



It is added by the former of thefe experimenters, that the produce of fuch 

 potatoe plants as have once been under the influence of this difeafe will con- 

 ftantly, if planted in the fame ground, continue to produce difeafed crops. 



There is (till another caufe to which this baneful difeafe in the leaf of the 

 potatoe plant has been afcribed ; which is, that of the feafon. It is remarked 

 that where the early part of the feafon is mild and warm, in fuch a degree as to 

 permit the plants to vegetate and fpring up in a perfect manner and to eita- 

 blifh themfelves well in the ground, there will be little or none of the difeafe ; 

 but that where the crop has been planted at too early a period, or where the 

 advance of warm weather is flow and late, the difeafe will (hew itfelf in a high 

 degree. Thus, where the fpring is late, cold, and frofty, and the potatoes fet at 



# partner s Magazine, vol. III. p. 217* + IM. J Billingfley, in Bath Papers, vol. VJ, 



Ibid, p. 218. 



