POTATO 



and used either for pig feeding or for manure. In 

 the north of Europe much spirit for drinking is 

 made from potatoes; it is called Potato- brain ly. 



The potato is subject to several diseases, the 

 chief of which is that serious fungous nllevlion now 

 commonly known as the jmtuttt ilnriute. This 

 disease was first obwvtd in ( iermany ; the earliest 

 known outbreak of a grave character occurred at 

 Liege in 1842. It broke out in Canada in 1*44. 

 and at once proved very destructive. In the 

 following year it made its appearance in the 

 British Isles, having been first observed in the Isle 

 of Wight. Its ravages in Ireland in 1846 and 1847 

 brought a terrible famine upon the small farmers 

 of that country, and at frequent intervals since it 

 has caused great loss in the potato crop. 



It has been proved beyond doubt that a particular 

 fungus always accompanies this peculiar and 

 destructive disease. The point is still doubted 



by some, but it is 

 now very generally 

 believed that this 

 fungus is the main 

 cause of the dis- 

 ease. Thismysteri- 

 ous fungus, Phy- 

 to/i/ithora infest- 

 am, runs through 

 a strange life-cycle 

 every year, and is 

 by no means easily 

 kept at bay. It 

 is l>elieved that, 

 except in tempera- 

 tures below 40" 

 and above 77 F., 

 it is always pres- 

 ent, ready to 

 pounce upon a 

 weak potato-plant, 

 and liable to de- 

 velop into an epi- 

 demic should the 

 climatic con.l i t ions 

 be favourable to 

 fungus-life. These 

 conditions are 

 damp, dull, calm 

 Beettooofpouto leaf. loer "rfac weather, and a 



p^r6,'eVi'ST "hydra? mnist or wet soil, 

 or thread of the fungm I'kytnphtliora enveloped in mists 

 infaiaia; <t,d, contdla or bud pore ; morning and even- 

 A o.pore: / BXMpore bunting ;., -pi" *,, t u- t 

 to liberate the zoogonidla ; g, antlu-r- "'- " 

 Idla or male portion, and A, oogonla the fungus is un- 

 or female portion, of a rungu<< m tin- able to l>ear a tern- 

 centraltliuofthel.-r,i.iit wi,..ti,,T , M . riltllre above 77" 

 portion, of the Phytophthora, a. } , , , . , 

 once aanerted, or of anothiT lun-ii,, u 



Pythlnur, l doubtful (<lanientr'i practical Import- 

 CAroHfde, 1891 X ance. The tomato 



is also subject to 



the attacks of the Phytophthora, but the ravages 

 of the fungus may be stop|M-d by raising the tem- 

 perature of the tomato-house to over 77 F. On 

 the potato crop the fungus generally makes its 

 appearance alxmt the third week in July, almost 

 invariably beginning its attack in the leaves of the 

 potato-plant. There it is first seen in a delicate 

 white bloom, accompanied by dark blotches, caused 

 by the spawn of the fungus having pierced the leaf 

 and set up putrefaction. With favourable climatic 

 conditions it wi'l now develop with great rapidity 

 a single genii multiplying ten thousand times iii 

 a few days in a tcnipe'ruture from 60 to 68 F. 

 The fungus ramifies throughout the leaves, blasting 



them as it pro, I,, and causing an oflensive 



odour which is now unfortunately familiar to the 

 farmer. The spore* of the fungus are -o light and 

 fine that they float through moist air, and are 



carried about and spread from one patch of potatoes 

 to another by insects and birds. From the leaves 

 the germs spread to the leaf-stalks, the stems, and 

 the tubers. The spawn readily pierces the kin of 

 the tulwr, consuming or rotting the cells, and 

 corroding the starch, and ultimately reducing tin- 

 potato to a black mass of lot tenne-. . In this last 

 stage of its yearly course of destruction the fungus 

 provides means of continuing its curious life. It 

 produces some kind of ' rest ing-spores,' which, pos- 

 sessed of amazing vitality, lie dormant during winter 

 and spring, and carry on the disease to the crop of 

 the succeeding year, which in its turn passes the 

 fungus through another round of its mysterious life, 

 to lie handed on again from crop to crop as before. 

 There is still uncertainty as to the precise character 

 of these spores ; but, "be what they may, their 

 tenacity of life is great 



Of the many remedial measures that have l>een 

 tried, the following have been found most useful 

 in preventing or mitigating the onslaught of the 

 fungus: (1) Earthing up the drills with a deep 

 covering of earth, with the view of preventing the 

 fungus from passing down the stem, or through the 

 soil to the tubers; |2) cutting off the diseased 

 potato-tops before the fungus reaches the tubers ; 



(3) removing and burning all dead and decaying 

 potato stems, leaves, and tuliers, especially alter 

 a crop which has been attacked by the disease ; 



(4) planting varieties which have been known to In- 

 exceptionally successful in resisting the disease ; 



(5) growing the potato crop under such general 

 cultural, sanitary, and mammal conditions as will 

 ensure to the fullest extent possible the healthy 

 and vigorous development of the crop; (6) careful 

 selecting and storing of potatoes to be used as seed ; 

 and (7) dressing the potato-tops, both before ami 

 after the appearance of the disease, with sulphate ,,i 

 copper. No certain prevention or absolute remedy 

 has as yet been discovered, but all these measures 

 have been carried out with advantage. The dis- 

 covery of the copper remedy is likely to be of great 

 importance to potato growers. This is the mix 

 ture about 3 to 6 parts of sulphate of copper and 

 quicklime to 100 parts of water which proved so 

 effectual in combating the allied parasite fungus, 

 I'l-ninospora in/estans, that attacks the vines, and 

 there is good reason to believe that it will lie 

 almost equally successful in averting the potato 

 disease. It is well known that a vigorous variety 

 of potatoes grown under conditions favourable to 

 its healthy development is most successful in 

 resisting tin- fungus. It is with the potato as 

 with a human being deprive it of wholesome 

 food and healthv sanitary surroundings, and dis- 

 ease will speedily ensue. The prevalence of this 

 particular disease in recent years is a sure indi- 

 cation of a deterioration in the constitutional 

 vigour of the cultivated potato. The other dis 

 eases from which the potato crop is liable to sutler 

 are Curl, Srab, Dry Rot, Wet Rot, and a fungus 

 known as Peziza post mini. ( 'nrl is a disease affect- 

 ing the foliage and general health of the potato- 

 plant, and does not seem to be necessarily connected 

 with the presence of any vegetable parasite or 

 insect enemy. .SVr6 is a disease of the tubers, 

 which become covered with brown, oblong, and 

 finally continent and cup -shaped spots, whilst under 

 the surface is a powdering of minute olive yellow 

 grains, a fungus called Tultfrrinin scabies, of the 

 divi-ion Il\ phoiiivcetes. llrt/ Hut is also ascrilied 

 to the growth of a fungus of the same order, 



iKiriuin snlani, and attacks the tubers either 

 when stored for winter or after being planted. 

 It was first observed in Germany in 1830, and 

 caused great loss in that country throughout many 

 years. The tisanes of the potato-tuner become 

 hardened and completely filled with the mycelium 



