NEW ENGLAND FARMER. 



39 



lurking in the system of the parent potato, is com- 

 municated to the progeny, fulfilling the Scripture — 

 "the iniquities of the fathers shall be visited upon 

 the children to the third and fourth generations." 

 Leaving out of the account, therefore, those few 

 cases, where, in consequence of unhealthy seed, 

 the indications of disease are as likely to appear 

 first in one part of the plant as another, the propo- 

 sition, that the rot in the tuber is subsequent to the 

 blight of the tops, is in accordance with truth as 

 well as general observation. 



The inquiry now arises, what is the cause of the 

 blight in the leaves and stalks of the potato? This 

 question has received a variety of answers. In 

 view, however, of all the light which now shines 

 upon the subject, we may say safely enough in a 

 general way, that the blight results from one of two 

 causes — either from the ravages of minute insects 

 or from some peculiar atmospheric influence. The 

 fact that it occurs every year at about the same 

 time, would be equally favorable to either of these 

 suppositions. Every species of insect has some dis- 

 tinct period, longer or shorter, assigned to it, in 

 which to commit its depredations. The rose-bugs 

 are a familiar illustration of this truth. So, too, 

 in the atmosphere, those subtle agencies, which are 

 fatal to life in the animal as well as in the vegetable 

 world, exercise their power only in fixed periods 

 and at regular intervals. Fevers are a familiar il- 

 lustration of this truth. Certain well-attested facts 

 would seem to indicate that some hidden malignant 

 agency in the atmosphere causes the blight. Those 

 " little black bugs," which have attracted unusual 

 attention the past season, undoubtedly aggravate 

 the evil somewhat, but the theory that they are 

 the sole authors of the mischief, has been not inap- 

 propriately termed by Prof. Harris a " humbug." 

 Uf'twi i contiguous fields, peopled alike with little bugs 

 and big bugs, of as many colors as the spirits in the 

 "Witches' Song — fields of similar soil, dressed alike 

 and planted with the same kind of seed at the same 

 time of the year, but of different aspects or expo- 

 sures, the one, open to the wind, is blighted, while 

 the other, protected from currents of air, escapes. 

 In the same field, rows, sheltered by the fence or 

 in gome other way, continue green and flourishing 

 when all the rest have withered. A few hills 

 covered with glass in the midst of a field, yield sound 

 potatoes, while all the rest are rotton. The track 

 of offensive fogs is suddenly and distinctly marked 

 by the blight. Other plants are affected simultane- 

 ously with the potato. Our own water-melon vines, 

 for instance, for the last three years have all been 

 struck fatally at the same time exactly as the pota- 

 to tops, near which they were growing. These 

 facts, and others of a kindred nature, all point to 

 the atmosphere as containing the noxious cause of 

 the disease ; but whether this noxious cause be an 

 excess of carbonic acid, or of carbonate of ammonia, 

 or of" sulphurous' chlorine mixed with certain other 

 gases," or of something else, is yet to be deter- 

 mined. It is an unfortunate fact, that, notwith- 

 standing the unparalleled researches bestowed upon 

 the subject, this vegetable cholera, the potato-rot, 

 like the Asiatic cholera, is under the control of laws 

 not yet fully discovered ; still the experience of 

 practical agriculturists and the experiments of 

 scientific men, warrant us in the belief that the dis- 

 ease may be alleviated and counteracted to a very 

 great extent. As a means of prevention or at least 

 of alleviation of the rot, we venture to make with 



some confidence — a confidence engendered by uni- 

 form success — the following 



RECOMMENDATIONS. 



First. — Plant early. The blight, as a general if 

 not universal rule, strikes the tops in the month of 

 August, at any rate not before that time. If 

 planted early, therefore, the sap of the plant may 

 all be assimilated and the potatoes be ripe before 

 the plague comes. Count Gasparin, an eminent 

 French scientific agriculturist, mentions, as report- 

 ed by the Commissioner of Patents, that " in the 

 south of Europe two crops of potatoes are obtained 

 in one year. The first crop is planted in March 

 and harvested in June ; the second is planted in 

 July, after the wheat is cut, and taken up in Oc- 

 tober. The first of these crops was absolutely 

 sound ; the second was diseased." 



Second. — Plant on light soils, with thoroughly 

 fermented dressing never put in the hill. The richer 

 the soil and the more abundant and concentrated 

 the manure, the ranker and more luxuriant will be 

 the vines. Let the blight strike the leaves of such 

 vines, when in full sap, and the heat of the weather, 

 however intense, will hardly be able to carry off by 

 evaporation the raw and uncarbonated juices ; and 

 if not thus carried off they will as a matter of 

 course become putrescent and eventually corrupt 

 their way down to the tuber. On the other band, 

 the lighter and feebler the soil, the smaller will be 

 the vines. The probability, therefore, is, that 

 should the blight strike them, the evaporation, es- 

 pecially if the weather should fortunately be dry 

 and hot at the time, would carry off the sap with- 

 out endangering the tuber. It is worthy of remark, 

 too, that if the soil should be light-colored, the re- 

 flection of the heat from it would greatly facilitate 

 the process of evaporation. 



Third. — Some have supposed, from the well es- 

 tablished fact that the potato soon decays when ex- 

 posed to the action of ammonia, that the blight is 

 caused by an excess of carbonate of ammonia in the 

 atmosphere. If this hypothesis is correct, sprink- 

 ling the tops at the right time with sulphate of lime, 

 or plaster, as it is commonly called, would remedy 

 the difficulty at once. The sulphuric acid of the 

 lhne drives out the weaker carbonic acid from the 

 ammonia, and takes its place ; while at the same 

 time the ill-treated carbonic acid makes suit to the 

 forsaken lime and is promptly accepted. In this 

 way, by a sort of unscriptural exchange of wives, 

 carbonate of ammonia and sulphate of lime become 

 sulphate of ammonia and carbonate of lime — an ar- 

 rangement, whatever may be said of its morality, 

 very profitable for the soil. 



Fourth. — A careful writer, A. G. Comings, be- 

 fore referred to, in a recent number of the Farmer, 

 thinks that carbonic acid is the cause of the rot, 

 and that whatever will remove or neutralize this 

 acid, " will be gratefully acknowledged by the af- 

 flicted potato." If this supposition is true, the 

 difficulty could be easily remedied by the application 

 of lime to the soil or to the tops or to both. The 

 carbonic acid would immediately unite with the lime 

 and form carbonate of lime, an insoluble salt, fa- 

 miliarly known as chalk or marble— a substance 

 alike inefficient for good or evil to anything that 

 grows. An equally sure remedy would be secured 

 by the agency of any one of the alkalies or of the 

 alkaline earths— the former making with the car- 

 bonic acid soluble carbonates, the latter insoluble 

 carbonates. 



