Cultivation of A ruble Land. Potatoes* Dij cafes oj. Curl. \ ] 3 



an early period, the crop is moftly injured by the curl ; while thofc that are 

 planted at a later period, and which are not fo much expofed to the effects of 

 cold and froft in their early growth, are more free from the difeafe. In proof of 

 this, it is obferved, that potatoes planted on elevated, hilly, and moift fituations, 

 which cannot befet fo early as in lower and more warm diftricts, and which fel- 

 dom appear perfectly above the ground before the latter end of May, are almoft 

 wholly free from the curl, on which account they are generally had recourfe to 

 as fced. 



But though many of thefe different caufes may operate in producing a ten 

 dency to the production of the curl in potatoe crops, they do not any of them 

 feem fully fufficient lo account for the difeafe in a perfectly fatisfactory man 

 ner. Further in veftigation into the nature of the difeafe is ftill wanting, in or 

 der fully to elucidate its caufe. It appears probable, however, that imperfect 

 culture, too early planting, celd, froft, and backward feafons, or other caufes that 

 have a tendency to diminim the vigor of the plants in the early ftages of their 

 growth and bring on a ftate of debility, may render the items as well as leaves 

 more fweet, and confequently more liable to be devoured by the attacks of ani 

 malcule, at the fame time that, from the imperfect confumption of the fweet nu 

 tritious material elaborated in the fet for the fupport of the young plant, in fuch 

 cafes, the roots may be more expofed to become the prey of infects, and in this 

 way the difeafe be produced. That fomething of this nature takes place feems 

 evident, from the circumftance of only fome of the plants being difeafed, while 

 others nearly adjoining them are in a healthy and luxuriant condition. 



But from whatever caufe this vegetable-malady may take its origin, no effectual 

 remedy feems yet to have been difcovered, but that of a frequent change of feed, 

 and having recourfe to fuch as is brought from a diftance, and from fuch diftricts 

 as are later, and have foils different from that in which they are to be planted. 

 Where the convenience of fhipping admits of it, the beft method is probably to 

 have the feed potatoes from Scotland, or fome of the northern counties of Eng 

 land; as experience has (hewn, that feed potatoes from thcfe parts of the ifland 

 feldora produce many difeafed plants for the firft or fecondyear.* Where infects 

 or animalcule are confidered as the caufe of curl, the changing of the feed 

 muftalfo be a principal mean of preventing the difeafe, as in this way we have 

 juft feen that fuch kinds of potatoes may be employed as they are not difpofed to 

 attack. But, befides this, it may be advifable to have this fort of crop planted 

 as little as poflible on the rich field or garden foils that have been long in a ftate of 

 tillage, and which of courfe abound moft with infects. 



* Rillingfley, in the Bath Papers, vol. VI. 

 VOL. II. Q 



