212 



Disease in the Potatoe. 



Vol. IX. 



Disease in the Potatoe. 



A COMMITTEE was Ordered by the Phila- 

 delphia Agricultural Society some time since, 

 to collect facts and materials for a Report on 

 the disease of the potatoe now prevailing. 

 As a part of their action, the following trans- 

 lation was made at their desire, of a paper 

 on the subject, by Professor Von Martins, 

 one of the most celebrated scientific men of 

 Europe, and they now publish it as a part of 

 the Report that they intend making at some 

 future time. 



The Potatoe epidemic of last year, or the 

 rot and scab of the potatoe, described by 

 Dr. C. F. Ph. V. Martins, Munich, 1842. 



Certain diseases of the potatoe plant have 

 been observed for more than eighty years. 



Curl. — The curl has been observed in 

 1776-79, in the principality of Goettingen, 

 and was described first in 1779. The so 

 called, white table potatoe, was almost tha 

 only sort attacked at first. In 1780-90, the 

 disease appeared frequently on the British 

 Isles, where it is said to have been first ob- 

 served in Ireland, whence it spread over 

 England and Scotland. John Holt mentions 

 two other diseases, as having appeared con- 

 temporaneously with the curl, viz: the can- 

 cer, which appeared, according to him, chiefly 

 in wet seasons; and the scab, which appeared 

 to be produced by dry seasons. 



In Hanover, tlie curl was first observed by 

 Thaer, in 1790, and in the beginning of this 

 century it showed itself most destructively 

 in Southern Prussia, since which time it has 

 shown itself at different places in Germany; 

 nowhere, however, to any great extent 

 Putsche, a monographer of the potatoe, gives 

 the following description of the curl ; the 

 plants attacked by it look very poor; ste 

 of a brownish green, or of a variegated 

 colour, with rubiginous spots, penetrating 

 into its pith; leaves rough, wrinkled, curled, 

 shrunk, with short petioles, covered with 

 spots, some of a light green, others of a yel- 

 lowish green colour. The pith of the sick 

 plants is often found rust-eaten, as it w^ere, 

 and parched. Early in the fall tlfe plants 

 turn yellow and perish. The few tubers 

 found, arc of a bad flavour, soapy and hardly 

 eatable, leaving, when eaten, a feeling of 

 scratching in the throat. The very skin of 

 the tubers is difterent from that of the sound 

 ones, its colour being partly brown, partly 

 of a pale yellow, or often with both colours 

 blended. 



Experience has shovv'n that certain varie- 

 ties of potatoes are more liable to this dis- 

 ease, than others; that they are less exposed 

 to it on mountains, than in the level coun- 



try; that the round and oblong red varieties 

 arc more readily attacked by it than the 

 white ones, and that this disease is propa- 

 gated by the seed-potatoes, and does not dis- 

 appear before the fourth or fifth generation, 

 even when the plants are well taken care of. 



llvst. — Another disease, which is men- 

 tioned as occurring contemporaneously with 

 the curl, is compared by Putsche with the 

 rust otthe grain. According to his descrip- 

 tion, small rubiginous spots appear on the 

 leaves of the sick potatoe plants, and spread- 

 ing gradually further, cover finally the whole 

 surface of the leaves. The perspiration of 

 the leaves being impeded, the stems become 

 parched and wither, or, where this latter 

 does not take place, black nobs are developed 

 in the tubers, which are harder and more 

 stringy than the rest of their substance. 

 The causes of this disease are unknown ; it 

 is often but of short duration, and is cured 

 by a gentle rain. 



Mr. Hampe mentions a disease of the po- 

 tatoe under the same name of rust, where 

 the tubers show spots of the colours of the 

 rust, with excoriations here and there. This 

 disease occurred in cold, wet summers, when 

 fresh dung had been brought upon the soil. 



Blue pox. — Another disease, called blue 

 pox or blue tumor, not yet observed by Mr. 

 Martins himself, has appeared in several 

 parts of the kingdom of Saxony, and in the 

 Upper Harz. According to Mr. Hampe's 

 description, blue spots and risings are first 

 observed on the skin of the tubers; after- 

 wards a dark coloured texture, similar to a 

 rhizomorpha — probably the forerunner of a 

 mushroom — appears, which surrounds the 

 tuber, penetrating even its interior, followed 

 by blue spots and streaks in the heart of its 

 substance. 



It is said to be produced by an improper 

 admixture of saw-dust and pine-straw, and 

 other imperfectly decomposed organic sub- 

 stances with the dung. Very wet weather 

 causes then the final outbreak of the dis- 

 ease. 



Rot. — The disease which has lately com- 

 mitted so great ravages in the potatoe crops, 

 seems to be the same that was described first 

 in 1769, by Gleditsch, and may be called the 

 rot. In Germany it has been called " rot of 

 the stem," "fruit cancer," "rot, or gangrene 

 of the tuber." This same disease seems to 

 have prevailed in the Saxon Voigtland, in 

 1783, when the summer was very hot and 

 very foggy. It was described in 1784, by 

 Dr. Ackermann. In the present century it 

 beiran to show itself first epidemically in 

 1830, in France and Germany; in the latter 

 country, in Rhenish Bavaria, Northern Bo- 

 hemia, Saxon Mountains, Erfurt, Anhaltj 



