The pests and blights of the tea plant
Watt, George, Sir, 1851-1930 | Mann, Harold H. (Harold Hart)
^ isP{\. fht lu^ p~ & Ui-£-<c 'to THE PESTS AND BLIGHTS OF THE TEA PLANT ( SECOND EDITION ) AGENTS. In Britain. Messrs. E. A. Arnold, 37, Bedford Street, Strand, London, W.C. Constable & Co., 2, Whitehall Gardens, London, S.W. Sampson Low, Marston & Co., St. Duns- tan’s House, Fetter Lane, London, E.C. P. S. King & Son, 2 &: 4, Great Smith Street, London, Westminster, S.W. Luzac & Co., 46, Great Russell Street, London, W.C. Kegan Paul, Trench, Trubner & Co., Charing Cross Road, London, W.C. B. Alfred Ouaritch, 15, Piccadilly, London, E. Williams and Norgate, Oxford. Deighton Bell & Co., Cambridge. On the Continent. Messrs. R. Friedlander & Sohn, Carlstrasse, 11, Berlin, N.W’. Otto Harrassowitz, Leipzig. Karl W. Hiersemann, Leipzig. Ernest Leroux, 28, Rue Bonaparte, Paris. Martinus N i j h off. The Hague. In India. Messrs. Thacker, Spink & Co., Calcutta and Simla. Newman & Co., Calcutta. V. Kalyanarama Aiyar & Co., Madras. R. Cambray & Co., Calcutta. S. K. Lahiri & Co., Calcutta. Thacker & Co., Ld., Bombay. Higginbotham & Co., Madras. Superintendent, American Baptist Mis- sion Press, Rangoon. Rai Sahib M. Gulab Singh & Sons, Mufid-i-Am Press, Lahore. A. J. Combridge & Co., Bombay. Mrs. Radhabai Atmaram Sagoon, Bombay. D. B. Taraporevala, Sons & Co., Bombay. THE PESTS AND BLIGHTS OF THE TEA PLANT (SECOND EDITION) BY SIR GEORGE WATT, M.B., C.M., F.L.S., C.I.E., OFFICIER D’ACADEMIE ; CORRESPONDING MEMBER, ROYAL HORTICULTURAL SOCIETY OF ENGLAND; REPORTER ON ECONOMIC PRODUCTS TO THE GOVERNMENT OF INDIA; AND HAROLD H. MANN, M.Sc., F.I.C., F.L.S., SCIENTIFIC OFFICER TO THE INDIAN TEA ASSOCIATION. CALCUTTA : OFFICE OF THE SUPERINTENDENT, GOVERNMENT PRINTING, INDIA. 1903. §ucc alia. 30* 4*. 69, CALCUTTA : GOVERNMENT OF INDIA CENTRAL PRINTING OFFICE, 8, HASTINGS STREET. r Wellcome institute LIBRARY Coll. welMOmec Call No. PREFACE TO THE SECOND EDITION. — ♦ — “The Pests and Blights of the Tea Plant” was first issued in 1898, and the edition then published became exhausted in less than two years. Numerous demands from planters in all parts of the tea districts showed that another was called for, and it was finally decided to accede to these various requests. In deciding to do so, advantage was taken of the appointment of a Scientific Officer by the Indian Tea Association in 1900, whose investigations, since that date, have carried him over all the more important tea districts of North India, and he was associated with the senior author in the work. The book takes therefore a much wider view of the questions dis- cussed than the former edition, which only professed to be a report of particular investigations conducted on special tours under orders of the Government of India in the Kangra Valley and Assam. In the present, on the other hand, not only has a considerable amount of information obtained since 1898 been utilised, but the book has beer, almost entirely re-written, and is no longer a report on certain specific journeys, but a general account of the pests and blights affecting the tea plant in India, and to a certain extent in Ceylon. We hope it may be found of service both in making the culture of tea more scientific than heretofore, and in placing in the hands of planters the best means of dealing with enemies and diseases of the plant, which seem to be growing in number and in virulence every season. GEORGE WATT. HAROLD H. MANN. Calcutta, March 1903. CONTENTS. — ♦ CHAPTER I.— Introduction — I. — Introductory II. — Sources of Information and Assistance III. — Need for further Investigation and Experiment CHAPTER II.— Plant Life— IV. — Nutritive and Reproductive Systems V. — Circulation of Sap. VI. — Conditions of Maturity . .... VII. — Practical Lessons to be learned , CHAPTER III. — Races of the Tea Plant, Seed Gardens and Improvement of Seed — VIII. — Varieties of Seed ..... IX. — Deterioration of Jat .... X.— Recognition of Different Forms .. XL— Peculiarities produced in the Garden XII. — Origin of Disease ..... XIII. — Improvement of Stock .... XIV. — Advantages of Uniformity of Stock. XV. — Hybrids ...... XVI.— Different Districts require Different Jats. XVII. — Seed Gardens ..... XVIII. — Utilisation of Surplus Tea Seed PAGE x 2 4 6 8 10 U 14 15 16 1 8 19 21 23 25 28 28 31 CHAPTER IV.— Hoeing, Weeding and Tillage generally- XIX. — Necessity of a Friable Soil and of Tillage . 35 XX.— Annual Deep Hoeing 36 XXL— Light Hoeing 38 XXII. — Cultivation of Slopes 41 XXIII.— Treatment supplementary to Hoeing . . 42 XXIV.- Weeds 42 CHAPTER V.— Drainage of Tea Gardens— XXV. — Water and its Relations to the Soil ... 45 XXVI. — Water and its Relations to the Plant . . 48 XXVII.— Indian Authors on Tea Drainage ... 51 XXVIII.— Conditions of Successful Drainage . . .52 XXIX.— Lateral or Feeder Drains . . . . 55 XXX.— Burial of Prunings in Drains ... 61 XXXI. — Treatment of Slopes .... 63 XXXII. — Irrigation in Tea  Importance of Pruning XXXIV.— Theory of Pruning. XXXV. — Treatment of the Young Plant XXXVI. — Pruning of Mature Bushes XXXVII. — Heavy Pruning XXXVIII. — Collar-pruning. XXXIX. — System of Pruning. .VII. — Plucking— XL. — Continuous Production of New Shoots XLI. — Systems of Plucking . . .. XLII. — “ Fine ” Plucking and “ Close” Plucking. XLIII.— Curious Methods of Plucking VIII. — Tea Manuring — XLIV. — General Principles of Manures and Manuring .... .. XLV. — Local Manures Available .. XLVL — Leguminous Trees among the Tea XLV II. — Bones and Oilcakes as Manure. Artificial and Chemical Manures XLV1II. — Systems of Manuring . . .. IX. — The Insect Pests of Tea — XLIX. — Introductory Observations T. — The Beetles ...... X. — The Insect PtSTS of Tea,— continued,— Lepidoptera LI.— The Butterflies and Moths and their Cater pillars ..... LI I. — Bag-worms, Faggot-worms, etc. LI 1 1. — Wood-boring Caterpillar. LI V.— Slug-like Stinging Caterpillars. LV. — Hairy Caterpillars .... _ LVI. — Moths with Mostly Naked Caterpillars , 0LVIL — Leaf-rollers and Leaf-tiers XL— The Insect Pests of Tea, — continued — Diptera — LVIII.— The Flies, Gnats, Gad-flies, etc. XII.— The Insect Pests of Tea,— continued,— Hymenoptera- LIX. — The Saw-flies, Gall-flies, Ichneumon-flies, Bees, Wasps and Ants .... XIII. — The Insect Pests of Tea,— continued,— Orthoptera— LX. — The Grasshoppers, Crickets, Locusts. XIV. — The Insect Pests of Tea,— continued, — Hemiptera — LXI.— The Tea-Mosquito, Tea Green-Fly, Tea Aphis, Plant-Lice, Scale-Insects, Plant Bugs ....... page 67 68 7i 78 89 94 98 101 104 114 117 119 122 140 •47 •53 161 •65 166 179 187 200 202 212 220 228 238 240 243 247 CONTENTS V PAGE CHAPTER XV. — The Insbct Pests of Tea, — continued, — Thysanoptera — LXII. — The Thrips ...... 320 CHAPTER XVI. — The Insect Pests of Tea, — continued,— Pseudoneu- ROPTERA — LXIH. — Termites or White Ants .... 322 CHAPTER XVII.— Arachnoidea— LX1V. — The Spiders, Mites, etc. .... 348 CHAPTER XVIII.— Other Animal Pests— LXV. — Nematode Worms or Eehvorms . . 372 LXVI. — The Snails and Slugs .... 376 LXVII.— The Julus-Worms or Millipedes . . 377 CHAPTER XIX. — Vegetable Parasites of the Tea Plant. — The Blights — LXVIII. — Parasites and Blights on the Leaves . . 380 CHAPTER XX.— Vegetable Parasites of the Tea Plant, — continued— LXIX. — Blights on the Stem ..... 392 CHAPTER XXI. — Vegetable Parasites of the Tea Plant,— continued — LXX.— Fungi on the Root . . . . .411 APPENDIX I. — Insecticide and Fungicide Materials .... 416a APPENDIX II.— Glossary of Vernacular Terms 416 b INDEX 417 LIST OF PLATES. PLATE PLATE I. — No. i. — Bush showing formation of roots on hard pan subsoil. No. 2. — Roots of bush on hard pan subsoil. {From. Photographs by H, H. Mann. ) Facing Page II. — No. i.—* Ageratum, a weed of tea-gardens. No. 2. — Various grasses of tea-gardens. (From Photographs by H. H. Mann) Facing Page 37 43 PLATE III. — Shoots produced in plucking experiment described on Page m — (From Sketch by jf. E. Aird.) Facing Page . in PLATE IV.— No. i. — Serica assamensis — (a) The beetle, enlarged. (b) The bettle at work on the leaf. No. 2.— Xyleborus fornicatus — (a) The larva of the beetle. (b) The pupa of the beetle. (c) The female beetle. ( d ) The male beetle. (e) Twig bored by the beetle. No. 3.— Lachnostema impressa — (a) The mature beetle. (b) The larva of the beetle. (c) The pupa of the beetle. (d) Antenna of beetle, much enlarged. No. 4. — Brachyaspistes tibialis— (a) and (b) The side and back views of the beetle. (All these are from Indian Museum Notes except No. 3, -which is after Cotes.) Facing Page . 167 PLATE V. — No. 1. — The bunch caterpillar — No. 2. — The bagworm, eating leaf— (From Photographs by T. H. Hall.) Facing Page . 182 PLATE VI.— No. 1.— Euproctis latifascia— (a) The caterpillar. (b) The male moth. ( c ) The female moth. No. 2. — Prodenia littoralis — (а) The caterpillar (б) The moth. ( c ) The chrysalis. Vlll LIST OF PLATES. No. 3. — Heterusia cingala— (a) The male moth. (b) The female moth. (c) The caterpillar. {d) The chrysalis, in a leaf. ( From Indian Museum Notes.) Facing Page PLATE VII. — No. 1. — Acanthopsyche subteralbata — (a) The larval case. (b) The male moth. {From Indian Museum Notes.) No. 2.— Clania variegata — (a) The male moth. (b) The head of caterpillar. (c) The chrysalis. (d) The female moth, separated from case. {After Dudgeon.) No. 3. — Larval case of clania variegata. ( After \ Dudgeon.) No. 4. — Clania crameri — (a) The larval case. (b) The larval case, cut open. ( c ) The larval case, from which the male moth has escaped. (d) The male moth. ( From Photographs by H. H. Mann.) Facing Page PLATE VIII. — No. 1. — Amatissa consorta — (a) The young larval cases. ( b ) The full. grown larval cases. PLATE No. IX.— No. 2. — Acanthopsyche snelleni — (a) The caterpillar at work on a leaf. (b) The chrysalis hung from a leaf. (c) The chrysalis from which the male moth has escaped. ( d ) The male moth. ( From Photographs by H. H. Mann.) Facing Page 1.— Zeuzera coffete — Showing caterpillar in its boring, cocoon, and moth. {After Cotes.) No. 2.— Biston suppressaria — (a) The caterpillar. ( b ) The chrysalis, back view. (c) Ditto side view. (</) The moth. {From Indian Museum Notes.) Facing Page 186 191 192 201 LIST OF PLATES. X PLATE X. — No. i. — Thosea recta — (а) The caterpillar and cocoon. (б) The male moth. (c) The female moth. No. 2. — Thosea cervina — (a) Back view of caterpillar. ( b ) Side view of caterpillar. (c) The female moth. (d) The male moth. The cocoon is also shown. No. 3. — Thosea divergens — (a) The cocoon. (b) The male moth. (c) The female moth. No. 4. — Belippa lohor— (a) The cocoon. (£>) The male moth. (c) The female moth. ( From Indian Museum Notes.) Facing Page PLATE XI. — No. 1. — The silken case of the bark-eating borer. No. 2.— The caterpillar of the bark-eating borer. {From Photographs by H. H. Mann.) Facing Page PLATE XII. — No. 1. — The moth of the sandwich caterpillar. No. 2. — The sandwich caterpillar at work. {From Photographs by T. H. Hall.) Facing Page PLATE XIII.— No. 1. — Cremastogaster rogenhoferi— {a) The red and black ant, enlarged. (6) The nest of the red and black ant. {From Indian Museum Notes.) No. PLATE XIV.— No. No. 2. — Helopeltis theivora— (a) Side view of the female tea- mosquito. {b) Back view of the female tea-mosquito. (c) The scutellar horn, enlarged. {d) Back view of the larva, about six days old. (e) Side view of the larva, about six days old. (/) Very young larva. {From Indian Museum Notes) Facing Page 1. — Shoot just attacked by the tea-mosquito. 2. — Bush badly attacked by the tea-mosquito. {Prom Photographs by H. H. Mann) Facing Page 204 323 235 247 263 X LIST OF PLATES. PLATE XV. — No. i. — Twig attacked by the tea aphis. ( From Photographs by J. L. Alexander.) No. 2. — Twig attacked by the tea green-fly. {From Photograph by H. H. Mann.) Facing Page . 289 PLATE XVI. — No. 1. — Ceroplastes cerifera, on tea twig. No. 2.— Carteria decorella — (a) Scale on twig, enlarged. ( b ) Ditto natural size. (c) and (d) Scales, much enlarged. ( e ) Male insect in winged condition. (/) Antenna of winged male insect. No. 3. Fiorinia these — (a) Scale (male), on under-surface of leaf. {b) Female scale, much enlarged. (c) Under-surface of female, removed from scale, enlarged. No. 4.— Ceroplastes myricse — (a) Under surface of female scale. (b) Scale on grass, natural size. (c) Upper surface of female scale. No. 5. — Eriochiton these — (a) Under surface of female scale. ( b ) Tea stem and leaf, with insects. (c) Upper surface of adult female scale. (d) Upper surface of male scale. (e) Side view of male scale. No. 6. — Lecanium watti — (a) Scale on twig, natural size. (b) Un der surface of female scale, enlarged. {From Indian Museum Notes.) Facing Page . 306 PLATE XVII. — The effect of the tea eelwoim on seedlings — {From Sketch by C. A. Barber.) Facing Page . 373 PLATE XVIII.— Tea blights — 1. — Grey blight on leaf, natural size. 2. — Section through a pustule of the grey blight fungus, magnified. 3 and 4.— Spores ot the grey blight fungus, highly magnified. 5. — Spores of the grey blight fungus, germinating : highly mag- nified, 6. — Leaf of tea plant, with blisters formed by blister blight. 7. — Section through a blister, magnified, LIST OF PLATES. XI 8. — Section through spore-bearing cells of blister showing conidio and basidio-spores, highly magnified. 9. — Basidio-spores, highly magnified. 10. — Conidio-spores, highly magnified. 11. — Branch of tea attacked with thread blight. 12. — Fruit of the thread blight fungus, much enlarged. 13. — Section through fruit of thread blight fungus, much enlarged. {From the Kew Bulletin.) Facing Page . 380 388 PLATE XIX. — No. 1. — The brown blight of tea — 6. — Brown blight of tea, natural size. 7. — Section through spore-bearing cells of brown blight, highly magnified. {From the Kew Bulletin.) No. 2. — The blister blight of tea — Upper surface of leaf. No. 3.-rThe blister blight of tea — Under surface of leaf. {From Photographs by T. H. Hall.) Facing Page PLATE XX. — No. 1. — Healthy tea bush. No. 2. — Tea bush affected with thread blight. No. 3. — Thread blight on tea twigs and leaves. {From Photographs by T.H. Hall.) Facing Page PLATE XXI. — No. 1. — Bush badly attacked with red rust, June 1901. No. 2. — Ditto. ditto. {From Photographs by H. H. Mann.) Facing Page PLATE XXII. — No. 1. — Wood attacked by red tust, showing cracks. {From Photograph by H. H. Mann.) No. 2. — Red rust on twig in autumn, enlarged 6 diameters. {From Photograph by T. H. Hall.) Facing Page PLATE XXIII. — No. 1. — The tea canker on young twigs. No. 2. — The tea canker on old stems. {From Photographs by H. H. Matin.) Facing Page PLATE XXIV. — Stump rot of tea, showing incrustation. {From Photograph by H. H. Mann.) Facing Page . 411 392  Photograph by H. H. Mann.) 2. — Representation of First to Ninth Prunings on Mr. L. Alexander’s System ...... (From Sketch by G. Watt.) 3. — First Plucking of Spring Shoots ( From Sketch by G. Watt.) 4. — First and Second Flushes ...... ( From Sketch by G. Watt.) 5. — Results of Second Plucking (1) ..... ( From Sketch by G. Watt.) 6. — Results of Second Plucking (2) . .... (From Sketch by G. Watt.) 7. — The Wireworm — Natural Size and Enlarged (After Miss Ormerod.) 8. — The Orange Beetle, showing back and side view of insect, antenna, and leg ...... (After Cotes.) 9. — The Green Beetle, showing back and side view of insect, and the antenna (After Cotes.) 10. — The Bunch Caterpillar, Cocoon, and Moth (After Cotes.) 11. — Caterpillar of Chserocampa alecto . . .. ( From Drawing by G. Watt.) 12. — The Lobster Caterpillar, Cocoon, and Moth (After Cotes.) 13. — The Spiral Faggot-Worm ...... (From Drawing by G. Watt.) 14. — The Limpet Caterpillar, attacking the upper surface of the leaf (From Sketch by G. Watt.) 15. — The Conical Psychid, attacking the under surface of the leaf ( From Sketch by G. Watt.) 16. — Thosea cotesi, showing the male and female moths and cocoon ...... (After Cotes.) 17.— The Blue Striped Nettle Grub, showing male and female moths and caterpillar " (After Cotes.) PAGli 82 IOO 105 108 112 lx3 170 171 1 77 182 183 184 190 194 198 207 209 XIV LIST OF ILLUSTRATIONS IN TEXT. FIGURE 18. — Gelatine Grub and Cocoon ..... {After Moore.) FIGURE 19- — Dasychera mendosa, showing moth and caterpillar. {After Cotes.) FIGURE 20. — The Tea Cutworm, showing moth and caterpillar {After Cotes.) FIGURE 21.— Ophiasa melicerte, showing moth and caterpillar .. {After Cotes.) FIGURE 22.— A Looper Caterpillar {After Cotes.) FIGURE 23. — The Tea Leaf Roller, showing Leaf-mining stage, Leaf-rolling stage, and caterpillar .... {From Sketch by G. Watt.) FIGURE 24. Caterpillar and Moth of Tea Leaf Roller {After E. E. Green.) FIGURE 25. — Moth of Tea Leaf Roller, much enlarged . ,. {From Drawing by Lord Walsingham.) FIGURE 26. — The Tea Tortrix, showing caterpillar, moth and caterpillar. {From Drawing by E. E. Green.) FIGURE 27. — The Tea Leaf Mining Fly, showing the pupal case . „ {From Sketch by G. Watt.) FIGURE 28. — Locust attacking Tea {After Cotes.) FIGURE 28.— The Tea Cricket— young larva ..... {After Cotes.) FIGURE 29. — Egg of Tea mosquito in shoot ..... ( After Dudgeon.) FIGURE 30.— The Abdomen, Hind Leg, and Ovipositor of Tea-mosquito {After Dudgeon.) FIGURE 31. — The Male of the Ceylon Tea-mosquito .... {From Sketch by E. E. Green.) FIGURE 32. — The Ceylon Tea-mosquito, showing adult female, egg of insect, and leaf with punctures ..... {After E. E. Green.) FIGURE 33. — Puncture in Msesa indica .... .. {After Dudgeon .) FIGURE 34. — The Tea Green Fly, showing mature and immature insects ......... {After Cotes.) FIGURE 35. — The Effect of Green Fly Blight ..... {After Cotes.) FIGURE 36. — Phromnia Marginella, showing adult and larva {After Cotes.) FIGURE 37. — The Tea Aphis, showing wingless and winged forms and antenna, enlarged {After Cotes.) PAGE 210 214 221 223 225 229 230 231 234 239 243 244 254 258 258 259 268 287 289 293 294 LIST OF ILLUSTRATIONS IN TEXT. XV FIGURE 38. — Kangra Bark Louse, showing the scale natural size, and larva enlarged {From Indian Museum Notes.) FIGURE 39. — Male scale of the White Tea Louse, showing colony of scales, and one scale enlarged {After Cotes.) FIGURE 39.* — The Thrip of Tea, showing larva, pupa and perfect insect {After Green.) FIGURE 40. — The Red Spider, showing male and female .. {After Cotes.) FIGURE 41. — The Yellow mite showing male and female, larva and eggs magnified, and damage on tea leaf {After Green.) FIGURE 42. — The Purple Mite, showing side and back view . , {After Green.) FIGURE 43. — The Pink Mite, showing adult and larva. {From Sketch by G. Watt.) FIGURE 44. — The Tea Eel worm, showing various stages. {From Sketch by C. A. Barber.) PAGE 305 308 320 351 361 366 369 374 THE PESTS AND BLIGHTS OF THE TEA PLANT. CHAPTER I. I NT ROD UCTION. i. The culture of the tea plant is of such a special character — perhaps not reproduced in any other agricultural industry in the world — that it is surrounded by difficulties the meaning and force of which can hardly be judged by the standards of ordinary agri- culture either in India or elsewhere. First, the tea plant itself is a perennial tree brought by cultivation to a shrub form, and then grown for leaf, while nearly all cultures of similar plants are made for the production of fruit or seed. Again, while this bush will grow on the greatest variety of soil, and with considerable variation of climate, yet such growth can only profitably take place under very strictly defined conditions, and variations which would often be ignored in ordinary agriculture would be fatal to the commercial production of tea in any district or country. If we add to these considerations the fact that the pests and blights which prey on the leaf and which hence can often be partially, at any rate, ignored in the usual crops, are here of vital importance as removing that for which the crop is primarily grown, an idea can be formed of the very special character of the industry, as agriculture, from whatever point of view it may be surveyed. INTRODUC- TION. Peculiar character of industry. 2 The Pests and Blights INTRODUC- TION. Isolation of industry. Scientific investiga- tions needed. SOURCES of INFORMA- TION. Tours in Tea Dis- tricts by Authors. Introduction. 2. These facts have led, with others, to the commercial growth of the plant in very narrow and well-defined areas, and partly as a result of this isolation, comparatively little is known of the real principles which underlie the success or failure of the industry in a particular place, and less of the methods of preventing or dealing with these enemies of the tea plant which have arisen as an inevitable conse- quence of the devotion of a large area in one district to the crop. 3. In the succeeding chapters we have endeavoured to represent certain aspects of the cultivation of the plant so far as they are known, but which, all of them, call for more careful investigation with a view to reforms. There exists sufficient presumptive evidence to justify the opinion that certain misapprehensions and defective methods of proce- dure have originated constitutional weaknesses that may be said to constantly predispose the plant to actual disease, or, in other words, to render the depredations of its enemies and parasites more alarm- ing than they might be otherwise. We have, therefore, in discussing the subject of the tea plant, its enemies and its diseases, advocated some such reforms in the treatment of the plant that may be found desirable and practicable and should necessarily accompany more specific efforts to battle with the pests and blights. II.— Sources of Information and Assistance , 4. In presenting the observations which we now propose to offer, it should be explained that those which are new are primarily based on the notes made during the journeys of the authors in the Indian Tea Districts from the year 1894 to 1902. These journeys were conducted by Dr. Watt, on behalf of the Indian Government, in the Kangra Valley (October and November 1894), in Assam (March to July 1895 and again in 1897), and in Darjeeling and the Dooars (October and November 1900), and by Mr. Mann, travelling for the Indian Tea Association, in Assam, Cachar, Sylbet and Chitta- gong (in 1900), in Assam and Darjeeling (in 1901), and in the Surma Valley and the Darjeeling Terai (in 1902). The present work is, however, intended purely and simply as a popular statement , since it would take many years to do justice to the subject or even to fully work up the mass of material that has been collected during the few months we have had in the districts. It is issued, as was the first edition, in the hope that it may prove of some slight of the Tea Plant. 3 Introduction. practical value, and also that it may awaken interest in subjects of enquiry that need to be very considerably extended before definite results in many directions can be obtained. 5. But while the primary responsibility for any novel statements made is our own, we have freely used the sources of information on the subject accessible to us. The following are the chief of these : — 1st. — The Journals and Proceedings of the Agri-Horticultural Society of India, more specially from 1865-1885,— the period of greatest interest by the Society in the subject of tea. 2nd. — Special publications of the Indian Tea Industry, including the annual reports of the Indian Tea Association from 1882 to 1901. 3rd. — Newspaper correspondence from 1873 to the present date, more especially the letters which originally appeared in the “ Tea Gazette ,” but which may now be conveniently consulted in the “ Tea Cyclopedia” and the “ Tea Planter's Vade Mecum.” Th e“ Tropical Agriculturist ” of Colombo has been found a mine of information for confirming or correcting observations made in India. 4th. — The planting papers of Calcutta — The Indian Planter’s Gazette” “ The Planter ,” and “ Indian Gardening and Planting ” and of South India — “ Planting Opinion.” 3th. — The Indian Museum Notes, more especially Mr. E. C. Cotes’s account of the Insects and Mites which attack the Tea Plant in India. 6th.— The invaluable aid of Sir W. T. Thiselton Dyer, the Director of, and of Mr. G. Massee, Cryptogamic Botanist in, the Kew Gardens, London, for several reports on Tea Blights. Among the most valuable papers on the Fungal Diseases of Tea are those written by Dr. D. D. Cunningham some years ago, and of these we have made the fullest use. In recent years Dr. Butler, the Cryptogamic Botanist to the Government of India, has given extremely valuable aid in the work- ing out of several previously obscure diseases. yth.—' The very great assistance, most generously afforded by Mr. E. E. Green, the Government Entomologist of Ceylon, who has for many years identified himself with the study of tea pests, and has, in consequence, discovered and investigated the life histories of a large number of obscure species. Mr. Green has not only examined practically all our pests, but has in return presented a most valuable set of the pests collected bv him in Ceylon. Similarly, Dr. A. S. R. Anderson and Mr. E. Barlow, formerly of the Indian Museum, SOURCES of INFORMA- TION. General. Botany. Entomology, 4 The Pests and Blights Introduction. SOURCES of INFORMA- TION. Co-operation of Planters. have helped a good deal in the identification of species. To the late Mr. L. de Niceville, of the Indian Museum, we owe a special debt of gratitude, as it was on a journey suggested by one of the authors, that he contracted the disease which carried him off in a few days. 8th. — The greatest debt is, however, owing to the large circle of planters whom it has been our good fortune to meet during our tours, and from whom the most valuable assistance has been obtained. Where so much valuable aid has been afforded one can hardly mention particular cases, but to Mr. Janies Buckingham, C.I.E., of Amgoorie, for general help, to Mr. T. H. Hall, now of Borsillah, for a good many photographs reproduced in these pages, and to Mr. Lindsay Alexander, now in England, but formerly at Pathalipam, Assam, for similar help, we are, among others, very specially indebted. gth. — Finally, the files of correspondence in the office of the Reporter on Economic Products to the Government of India have been freely drawn upon and have been of great assistance. RESULTS not final. III. —Need for further Investigation and Experiment. 6. In this work we however make no pretence of finality in any way. The methods of cultivation described, or recommended where they differ from those usually in vogue, require the most thorough and critical examination in the field before use on a large scale. We perfectly recognise that it is impossible to know whether a method eminently successful under one set of conditions will be equally successful, or successful at all, in another district or under another set of conditions. This being the case, we should be the first to deprecate radical departures on a large scale from regular practices until on a small area in the same district such departures have proved to be a success. But, on the other hand, there seems little doubt that deterioration of the tea in existence on most, though not on all, gardens, to whatever cause it may be due, has been, and is, taking place, and this deterioration indicates that some part of the usual procedure of planting is defective. It may be laid down as a universal rule in agriculture that where, owing to the utilisation of land for some years, that land becomes agriculturally less valuable, something is wrong either in the method of treating the soil or the plant,— or else a change is occurring in the climate. of the Tea Plant. S Introduction. 7. That any change of moment is occurring in the climate of the Indian Tea Districts is, as yet, not proved. The deterioration which is undoubtedly occurring in most old gardens is probably, therefore, due to one or the other of the remaining two causes named, or to both, and the remedy seems to be to examine the soil which has long grown tea and ascertain the nature of the exhaustion which has taken place ; and furthermore to . examine the bushes and obtain information as to the effect, which the usual methods of planting— cultivation, pruning and plucking- have had on the wood, the leaf, and the general character of the plant. So far perhaps work has been carried, but it needs very careful experi- mental as well as observational work on land and on bushes under actual tea garden conditions before it can be said that the results are always really and absolutely applicable. It has not been possible to carry out such experimental work as yet, though there seems a distinct probability that this may be feasible in the near future. In the meantime the results obtained by careful observation in the field, by laboratory analyses and experiments, and by a certain number of field experiments are here placed on record in a succes- sion of chapters on — ( a ) Plant Life in general, with special reference to the growth of a plant for leaf production. (b) Seeds and Seed Gardens. (c) Hoeing and Weeding. ( d ) Drainage. (f) Principles of Pruning. (/) Plucking. (g) Manuring. After this follows a more detailed description of the various insect pests and fungal blights which attack the bush, and the methods which have been or may be found useful in dealing with them, distinction being made between those of primary and of secondary importance at present. RESULTS not final. Possible climatic changes. Need for examination of soil and bush. Conf. with yarns, 171, 183, 211, 213. Summary of chapters. 6 The Pests and Blights Plant Life. PLANT LIFE. CHAPTER II. Conf. with para, 98. PLANT LIFE. 8. While fully conscious that it would be both undesirable and unsatisfactory to attempt in a few pages a scientific account of even the leading features of Plant Life, it may serve a useful purpose, nevertheless, if we endeavour to bring to mind some of the leading facts that should guide the tea-planter in his out-door operations. We shall, therefore, only touch on those aspects of this very in- structive study that have a direct bearing on Hoeing and Weeding, Draining, Pruning, Plucking and Manuring. It should accordingly be understood that the few brief paragraphs that comprise this chapter have been offered with one object, namely, to heip to elucidate certain practical recommendations which we feel called upon to lay before those interested in tea-planting. Our remarks must not, therefore, be judged according to the standard of advanced research into the physiology of plants. Nutritive and repro- ductive functions. IV.— Nutritive and Reproductive Systems. 9. Parts of the plant. — It is customary to speak of the parts of a plant as consisting of two sets, Nutritive and Reproductive. The former are concerned with the life of the individual, the latter with perpetuation of the species. The nutritive organs may be said to be the Roots, Stem, Branches and Leaves ; the reproductive, the Flowers and Fruits with their ultimate offspring — the Seed. Mouths of the plant. Food of plant. Although not absolutely correct, it may be said that the roots are the mouths of the plant, and that the leaves are both the lungs and the stomach. The food of plants may be expressed briefly as Air, Water and Mineral Substances. The atmosphere being but in- directly under the control of the agriculturist, his attention is mainly directed to the soil. Under the chapters on Hoeing and Draining, an effort will be made to indicate the manner in which Value of air. the cultivator may take full advantage of the valuable properties of air. By drainage, moreover, not only can the soil temperature be raised, but even climatic conditions beneficially influenced. Composition of air. Air may be regarded as consisting of oxygen and nitrogen, two gases that are intimately mixed up, but which remain chemically of the Tea Plant, 7 Plant Life. free from each other — a wonderful fact and one of the greatest im- portance. During thunderstorms, however, actual union lakes place between a certain amount of these two gases, and a compound results which by a further union with the elements of water becomes Nitric Acid. That acid is of the greatest value to the plants since it contributes toward the decompositions of the soil by which insoluble substances are rendered soluble. But the air also contains a very considerable amount of Carbonic Acid gas, and a lesser amount of an equally valuable compound, Ammonia. io. Respiration. — Animals inhale the air in order that its free oxygen may be combined with the waste carbon of their bodies form- ing carbonic acid, and this is exhaled. Plants breathe by pre- cisely the same principle, but added to their respiration they have a process of digestion. Under the influence of the light rays of the sun, acting on the green colouring matter of the leaves, the carbonic acid of their exhalation, as also the carbonic acid of the atmosphere, is decomposed, the carbon retained as a food material, and pure oxy- gen exhaled. During night, however, this absorption of carbon does not take place, so that the respiration of plants is then demonstrable as identical with that of animals. ii. Food 3Iaterials. — The food of animals has to undergo a regular series of chemical changes collectively designated Digestion, before it can be absorbed or utilized. Moreover, the food materials of animals are very different from those of plants, since animals are unable to live upon earthy or inorganic substances. The animal is in fact entirely dependent on the plant for the preparation of its food. Plant food may be said to be oxygen, hydrogen, nitrogen and carbon, (all derived from air and water) also certain earthy materials obtained from the soil. The plant possesses no stomach, strictly so speaking, but nevertheless its food materials have to under- go chemical changes, by a process designated Assimilation, which closely corresponds to digestion, before they can be built up in the tissues of the plant. Although the proportion of mineral matter eaten by plants is comparatively small, the higher plants at least cannot live without certain mineral substances. Each plant may be said to demand certain inorganic substances, otherwise it will not grow. The agriculturist, in his efforts to improve the soil, has, therefore, to direct attention chiefly to these indispensable inorganic 1 NUTRITIVE and REPRODUC- TIVE. Nitric acid. Conf. with para. 15. Respiration, Conf. with para. 13. Chlorophyll, Conf. with para. 13, Food materials. Assimilation. Conf. with para. 98. 3 The Pests and Blights Plant Life. NUTRITIVE and REPRODUC- TIVE food substances. During the process of assimilation the food mate- rials are built up into various organic compounds, and these again are utilized in the formation of plant tissues. Briefly, the organic compounds of plants may be said to be : — Chemical compounds of plant tissue. ist. — Starches and compounds of a similar type, built up of oxygen, hydrogen and carbon, in varying proportions. Of this nature maybe mentioned starch proper; cellulose or the constituent of wood and fibre ; gum; and lastly, sugar. 2nd. — Protein compounds. These contain nitrogen in addition to the oxygen, hydrogen and carbon of the starches, as also smaller proportions of sulphur, phosphorus, etc. Of this nature may be mentioned gluten ; albumen ; casein, etc., etc. All living and growing vegetable tissues contain a certain proportion of protein matter and a liberal supply of nitrogen is, therefore, indispensable to the life of plants. Let it be added in passing that nitrogen may be regarded as derived mainly, if not entirely, by the roots. 3rd. — Oils or Fats. — These all agree in containing less oxygen than would be necessary to convert their hydrogen into water. 4th. — Water, an article of food the elements of which are occasionally separated and utilized in the formation of certain compounds. CIRCULA- TION. Conf. with para. 90. V. — Circulation of sap. 12. Growth. — On placing a seed under the conditions of germi- nation, the first change that takes place may be said to be that a por- tion of its protein undergoes a sort of fermentation by which a part of it is converted into a substance very generally designated Diastase. That substance is no sooner produced than it acts upon the store of Growth. Conf. with para. 21. starch (also contained within the seed) and converts it into a form of sugar, which being soluble thus increases the specific gravity of the cell-contents. Osmose is in this way brought into action, that is to say, water is absorbed. It passes through the component cell-walls of the seed, obedient to a law of nature that a balance must be at once struck, should the specific gravities of two adjacent fluids be disturbed. 13. The latent embryo being thus supplied with soluble food materials commences to grow. No sooner has its young stem and of the Tea Plant. 9 Plant Life. leaves ascended above ground than their cells become charged with a green colouring matter ( Chlorophyll ) the services of which are now eminently required. With the exception of the moisture and the snjall amount of soluble substances absorbed, growth hitherto must be viewed as simply the result of the embryo having been able to use the materials which had been stored up for it within the seed. It may in fact be defined as growth, as the result of re-arrangement. But no sooner have the roots penetrated the soil and the leaves unfolded in the atmosphere than three distinct phenomena make their appearance : — ist. — The sun by evaporation withdraws moisture from the leaves and thus the specific gravity of their cell-contents becomes increased owing to concentration. 2nd.— The leaves commence to breathe and purify thereby what may even already be impure. jrd. — The leaves decompose the carbonic acid of the atmos- phere inhaled by them, retain the carbon and set free the oxygen. 14. Ascent of Sap. — For convenience we may view these conditions as originating the circulation of the sap and commencing the process of assimilation. It has been stated that by osmose the specific gravity of the cell-contents of the delicate roots that had emerged from the seed, was lowered. But by transpiration from the cells of the leaves, the specific gravity of their cell-contents is now raised. In consequence the cells above draw on the cells below for an extra supply of moisture. This suction from above and osmotic pressure from below may thus be viewed as sufficient to originate a circulation of fluid through the plant tissue. The ascending current is called the Crude Sap, because, while it contains many of the ne- cessary food materials, they exist in a condition that cannot be uti- lized. The crude sap has to undergo a series of changes which, as already stated, are collectively designated the assimilation or diges- tion of plants. 15. But let us see what the crude sap contains, before we pro- ceed to discuss the changes of assimilation. Water of course consti- tutes by far its largest proportion and is in addition the medium, through which other substances have been absorbed — for the food materials of plants must be soluble. Held in solution, then, the CIRCULA- TION of SAP. Action of chlorophyll. Conf. with para. 10. Ascending 01- crude sap. Conf. with paras. OS, 150. Water. to The Pests and Blights CIRCULA- TION of SAP. Origin of Nitrates. Conf . with para , 9, Plant Life. crude sap contains compounds of nitrogen and nitrates. These ni- trates have been derived from various sources, such as the ammonia of decomposing organic matter and of the air, nitrates formed by the nitric acid of the air, and last but perhaps the most important of all from the nitrogen fixing organisms of the soil which originate in pari, at any rate, from the roots of leguminous plants. Lastly, the crude sap contains the mineral substances derived from the soil. Position of current. 1 6. Avoiding all controversial points, it may not incorrectly then be regarded that the current of water, laden with these food materials, ascends through the young layer of wood, immediately underneath the bark, being propelled by the following amongst other forces : — Causes of circulation. osmotic pressure below, suction due to transpiration above, the che- mical affinity that the cell-walls possess for water, capillary attraction between layers of cells and tissues, and, lastly, the decomposition of water and the utilization of its component elements during assimilation. Assimila- tion. 17. Assimilation and Descent of Sap.— By whatever means it may be, this is certain, that a steady current of sap ascends amongst the young wood cells and, on reaching the leaves, is acted on in the three ways already mentioned. It is concentrated by perspiration, it is purified by respiration, and it is carbonised by decomposition of the carbonic acid gas of the atmosphere. This carbon entering into combination directly with the elements of water, forms one or Descending sap. other of the starches. By union with water, with carbon and with the nitrogen from a nitrate, protein matter is produced. In this way, then, many nutritious food-stuffs are formed. The sap is now digested or as it is called assimilated, and it slowly makes its way downwards by diffusing itself through the entire substance of the plant. From the elaborated Descending Sap the various tissues and structures are able to pick out the compounds which they require and these built up within the cells, cause them to grow, and finally, when mature to multiply, so that with vigorous circulation of sap rapid growth takes place. V I.— Conditions of Maturity. Plant structures. 18. Plant Tissue. — The cell may be said to be the ultimate structure. It is a small sac, the containing wall of which is composed of cellulose. One of the most striking peculiarities of the cell-wall has already been mentioned, but may be here more pointedly recapitulated. Although devoid of pores of any kind, fluids pass of the Tea Plant. ii Plant Life freely through in obedience to the law of osmose. The cell-contents are of a liquid nature with sometimes solid materials formed within. Many microscopic plants consist simply of one cell. Others are built up of cells all of one shape and size, like the bricks of a wall, only that they are living bricks that increase in number by cell division. In still a third class of plants the cells are of different shapes, many compacted together and even fused, end on end, into tubes that ulti- mately form fibrous tissue and wood. These changes in the shape and also in the special adaptations of the cell, are brought into exist- ence in obedience to the demand for the accomplishment of fixed and definite functions, attributed to the various organs of plant struc- ture. The walls of the cells are thickened when the object is to form wood ; the cell-walls in that case gradually become impervi- ous to fluids and thus cease to participate in the circulation of sap. Wood is, therefore, developed to give strength and support to the young growing shoots and to bear the flowers and fruits. 19. Reproduction. — But the formation of wood, beyond certain limits, when the object aimed at by the cultivator is a free circulation of sap and rapid production of shoots, may be regarded as an un- favourable and undesirable symptom. It is an unmistakeable sign of the advance of age and will assuredly be followed by the production of flowers and fruits. When, therefore, a plant has attained maturity, reproduction becomes the governing principle of its future life. Should it be prematurely aged, by adverse circumstances, it may similarly be seen to put forth an effort to make up for the fast approach of its own death by the production of the germs for a new generation. V II.— Practical Lessons to be Learned. 20. Continuous Growth— Flushing. — To the tea-planter, therefore, the production of unnecessary wood or of flowers should be looked upon as untoward circumstances. In both cases pruning be- comes a necessity. But pruning must go hand and glove with soil im- provement, for if a check be given to the natural desires of the plant viz., to provide for a new generation, without supplying it with the mate- rials necessary for continued growth, the shock may prove fatal. But it should never be forgotten that the cultivation of the tea plant, figu- ratively speaking, might be characterised as a forced procrastination in the fulfilment of a universal law of nature. And the simile which CONDITIONS of MATURITY. Formation of wood. Production of flowers Continuous growth — flushing. Improve- ment of soil. Conf. with para. 95. 12 The Pests and Blights Plant Life. PRACTICAL LESSONS- Old Wood. Roots. Demands of growth. Conf. with paras. 19-13. Flushing. Bleeding. Uprooting and replanting. Conf. with para. 918. it is here desired to draw is but partially true. The lower portion of the stem may represent a seared old age, forced through pruning and cultivation, to continually renew its youth. But the presence of old wood in the stem, by retarding circulation and constantly forcing on the younger upper shoots the necessity to flower and fruit, must be injurious to the planter’s aims and objects. 