214 



Disease in the Potatoe. 



Vol. IX. 



Manure. — Most injurious seems to be the 

 bringing the seed potatoes in immediate con- 

 tact with the dung. Manure is best applied 

 before the beginning of the winter season. 

 Dung that is too fresh and too hot, is in 

 general injurious. 



Moisture. — With regard to moisture, sta- 

 tionary wetness is undoubtedly injurious. In 

 its native country the potatoe is found thriv- 

 ing in a dry soil, which at certain seasons is 

 strongly penetrated by moisture. 



A rotation of crops appropriate to the lo- 

 cality, has been observed to be favourable to 

 the productiveness of the potatoe. 



Weather. — With regard to the weather 

 as an external cause of the rot, we may 

 conclude from all the reports that have 

 come in, that most parts of Germany that 

 have been ravaged by this epidemic, have 

 rather suffered by too great dryness, than by 

 too great moisture. A long continuance of 

 dry weather in spring, proved very injurious 

 to the sprouting of the seed potatoes in the 

 Palatinate. On the lower Rhine, on the 

 contrary, wetness was found to favour the 

 breaking out of the rot ; the same has been 

 the case in the Harz mountains, and in Bo- 

 hemia. 



A very singular fact observed in several 

 villages of the Palatinate, was that of pota- 

 toes, taken from one and the same cellar; 

 all those laid in the morning sprouted, whilst 

 all those laid in the afternoon failed. 



Martins is opposed to the opinion of those 

 who seek the cause of the rot, in insects la\^- 

 ing their eggs on the potatoes, as but very 

 rarely any eggs have been found on them. 

 He is on the other hand not disinclined to 

 side with those agriculturists, who believe 

 that two different sorts of potatoes of very 

 different degrees of acclimation, being plant- 

 ed aside of each other, the one less acclima- 

 ted, will e.xert an injurious influence upon 

 the other. In the year 1781, already seve- 

 ral farmers ascribed the cause of the curl to 

 the cultivation of the lately introduced 

 large American or ISeio England hog po- 

 tatoe, the same probably as the English 

 cluster, or perhaps also to that of the kin- 

 dred Howard, or large cattle potatoe, in the 

 neighbourhood of the red potatoe then gene- 

 rally cultivated. 



Internal causes. — Martius has observed 

 the rot attacking only the late sorts. In 

 the Palatinate, the gelbe und loeisse Speise- 

 Karloffel, i. e., yellow and white table pota- 

 toe, and among these, more those of a softer 

 and proportionally more juicy texture, were 

 chiefly attacked. In Saxony, Meklenbiirg, 

 and elsewhere again, all sorts were attacked 

 indifferently. 



Points to he observed in the cultivation 

 of the potatoe. — In cultivating the potatoe, 

 we have to attend to the following points, 

 when we wish to obtain a healthy crop. 1st. 

 The seed potatoes are to be raised separately 

 from those destined ibr food, since the growth 

 of the eyes in the tubers takes place at the 

 expense of the amylum contained in them. 

 In gathering and bringing home the pota- 

 toes, they ought to be guarded from all un- 

 necessary concussions. 



2nd. In preserving them in cellars, they 

 are to be kept from freezing, but so as not 

 to prevent a free draught of air, since they 

 begin to perspire soon after being brought 

 in, chiefly in confined places, and continue 

 to do so for four to six weeks, which perspi- 

 ration, when not allowed to evaporate, occa- 

 sions their decomposition. 



3rd. Those tubers will prove the best for 

 raising vigorous plants, whose eyes are yet 

 quite short, but juicy ; and where the tubers 

 have just begun to spend a part of their 

 nutritive matter in the formation of the 

 eyes, which is recognized by a slight with- 

 ering of them. 



4th. Great care is necessary in propa- 

 gating the potatoe by cuttings, as those 

 whose eyes were wounded, have been found 

 particularly liable to the rot. Chiefly the 

 upper part of the tuber, lying opposite to its 

 point of connexion with the plant, and hav- 

 ing the greatest number of eyes, ought to 

 be used for planting. The cuttings ought 

 to be kept for eight days at a moderately 

 warm place before planting them, or to be 

 strewn with wood ashes or gypsum on the 

 cut surface, in order to make them less ac- 

 cessible to the moisture of the soil. 



5th. In laying the cuttings, care must be 

 hnd to lay them with their eyes upwards. 

 Wlien, instead of entire tubers, cuttings 

 only are laid, it is important whether the 

 earth around them lies loosely or closely, 

 ond in what manner the ploughing is done. 

 The rot has been in general less frequently 

 observed, where instead of the plough the 

 spnde is used. With regard to the manure, 

 Martius thinks it is best to cover the cut- 

 tings with earth, and then first to spread the 

 dung over them in the furrows. 



In the ore mountains of Saxony, the farm- 

 ers have improved their potatoe crops in 

 quantity, as well as in quality, by laying 

 whole tubers, instead of cuttings, and pre- 

 paring for every one of them a couch, as it 

 were, of a handfull of dried leaves, or of 

 chopped straw, and covering tliem after- 

 words with earth. 



Gth. It is necessary to heap up the earth 

 around the stem of the potatoe plants, and 



