ENTOMOLOGY LIB- STlje Eural Science Series EDITED BY L. H. BAILEY THE SPRAYING OF PLANTS A. MILLARDET, PROFESSOR IN THE ACADEMY OF SCIENCES, BORDEAUX, FRANCE. , (See page 26.} THE SPRAYING OF PLANTS A SUCCINCT ACCOUNT OF THE HISTORY, PRINCIPLES AND PRACTICE OF THE APPLICATION OF LIQUIDS AND POWDERS TO PLANTS FOR THE PURPOSE OF DE- STROYING INSECTS AND FUNGI BY E. G. LODEMAN INSTRUCTOR IN HORTICULTURE IN THE CORNELL UNIVERSITY WITH A PREFACE BY B. T. GALLOWAY CHIEF OF THE DIVISION OF VEGETABLE PATHOLOGY, UNITED STATES DEPARTMENT OF AGRICULTURE gorfc THE MACMILLAN COMPANY LONDON : MACMILLAN & CO., LTD. 1897 All riff/its reserved COPYRIGHT, 1896, BY MACMILLAN AND CO. Set up and electrotyped January, 1896. Reprinted September, 1897. *** THESIS PRESENTED TO THE CORNELL UNIVERSITY FOR THE DEGRKE OF MASTER OF SCIENCE. Nortoooti J. S. Gushing & Co. — Berwick & Smith Norwood Mass. U.S.A. SEINER MUTTER IN INNIGSTER LIEBE ZUGEEIGNET DER VERFASSER PREFACE. IN looking back over the past ten or twelve years, it is dif- ficult to realize the rapid advance made in combating the insects and fungi which attack our cultivated plants. It is not going too far to say that the discoveries made within this period have worked almost a revolution in certain lines of agriculture. So phenomenal has been the progress in this direction that we are sometimes led to think that we have gone forward too fast, for in our intense desire to make the work thoroughly practical we have in many cases merely skimmed the surface, overlooking some of the most important funda- mental questions involved. However this may be, the fact remains that America to-day stands well to the front in the discovery and application of practical methods of dealing with the numerous insect and fungous enemies of cultivated plants. The advance in this department has been so rapid that it has hardly been possible for investigators to keep track of all that has been written on the subject, nor has it, under the circum- stances, been an easy matter to pause and consider what is to be the final outcome of work of this kind. This seems to be a fitting time, therefore, to take a broad survey of the subject in order that we may see where we stand. Mr. Lodeman has done this in the present volume, in which is given a clear, con- cise statement of the existing condition of our knowledge on ix x Preface. the spraying of plants and the fundamental principles under- lying this operation. As to the future, it can only be said that the prospect for broadening the work so well begun is exceedingly promising. As yet it cannot be stated that we have a well-defined science of plant pathology, but gradually the investigations and thought in this direction are being crystallized. Tt is now realized that to truly understand and appreciate pathological phenomena we must be familiar with physiology, the normal life processes of plants. After all, the highest aim of the investigator in this field of research is not to deal only with effects as he finds them, but to study causes, as it is only by this means that the true nature of many of the phenomena involved can be obtained. Following this line, we shall in the future look for a science capable of elucidating the problems which form the very basis of agricultural and horticultural pursuits. B. T. GALLOWAY. WASHINGTON, D.C. CONTENTS. PART I. THE HISTORY AND PRINCIPLES OF SPRAYING. CHAPTER I. EARLY HISTORY OF LIQUID APPLICATIONS. First Applications to Plants — Present Distribution of Insect and Fungous Parasites — Oceans as Barriers — Protective Applica- tions the Most Effective Measures — Spraying Defined — Early Recommendations — Vinegar — Rue — Urine — Dung — De- struction of Plant Lice — Tobacco, Water, Powder — Soap — Soot — Sage — Hyssop — Wormwood — Lime — Petroleum — Turpentine — Tansy — Leek — Hellebore — Oils — Sul- phur — Paints — Washes — Forsyth's Composition — Ashes — Sand — Plaster — Burnt Bones — Decoction of Walnut Leaves — Train-oil — Whale-oil — Flax Rubbish — Sea-weed — Sea- shells — Sea-sand — Mortar Rubbish — Clay — Tanner's Bark — Leather Scraps — Salt — Corrosive Sublimate — Alcohol — Potato Water — Decoctions of Elder — Bitter Herbs — Pepper — Lye — Pot and Pearl Ashes — Tar — Hot Water — Soft Soap — Farmyard Drainage — Brimstone — Burdock Leaves — White Hellebore — Nitre — Whale-oil Soap — Nux Vomica — Scotch Snuff — Cayenne Pepper — Aconite — Pigeon Dung — Eau Grison — Quassia Chips — Copper Sulphate — Various Formulas containing these Ingredients — Applications recom- mended against Canker — Cantharides — Plant Lice — Me- chanical Injuries — Canker-worms — Red Spider — Insects on xi xii Contents. Melons — Scale Insects — Apple-tree Borer — Slugs — Cater- pillars— Bed-bugs — Brown Turtle Insect — White Scaly Coc- cus — Pine-bug — Peach Mildew — Woolly Aphis — Aphis — Thrips — Wood-lice — Insects on Fruit Trees — Currant Worm — Rose-bug — Mildew on Chrysanthemum, Grape, Gooseberry — Curculio — Rose Mildew. Pages 1-18 CHAPTER II. SPRAYING IN FOREIGN COUNTRIES. IN FRANCE. Discursive Trials of Fungicides (page 19). — Acetate of Potassium — Sulphur — Downy Mildew of the Grape in France — Powdery Mildew of Grape — Powders — Iron Sulphate — Plaster — Fungivore — Pear Diseases — Sulphuric Acid — Copper Sul- phate — Spores affected by Copper Sulphate — Treatment of Grape Anthracnose — Copper Sulphate upon Posts, Tying Materials, and Stocks — Phenic Acid Emulsion. Origin of the Bordeaux Mixture (page 24). — An Accidental Dis- covery — Early Experiments in its Use — Downy Mildew first systematically treated with Bordeaux Mixture — Other Mate- rials tested — First Published Formula for the Bordeaux Mix- ture — Tomatoes sprayed with Bordeaux Mixture for Rot — Recommendations for Treating Potatoes — Treatment of Beaune — Treatment of Millardet — Spraying with Simple Solution of Copper Sulphate — Spraying with Milk of Lime — Treatments with Powders. Origin of the Ammoniated Copper Fungicides and Various Com- binations (page 30). — The Use of Eau Celeste — A Dilute Bordeaux Mixture — Bouillies Bourguignonnes. Poicders (page 32). — Podechard's — David's — Sulphosteatite — Sulfatine. Perfection of Fungicides (page 34). — Stock Solutions for the Bordeaux Mixture — Treatment of A. Bouchard — Modified Eau Celeste — Bouillie Berrichonne — Treatments for Anthracnose of Grapes — Tests of Fungicides — Grape Black Rot in France — Bordeaux Mixture containing some Dissolved Copper — Bor- Contents. xiii deaux Mixture Celeste — Bordeaux Mixture and Molasses — Tests of Fungicides — Bordeaux Mixture, Various Formulas and Combinations — Treatments for Pear Diseases. Insecticides (page 50). — Soap — Alcohol — Aloes — Oxalic Acid — Fichet's Insecticide — Petroleum — Kerosene Emulsion — Sul- phide of Potassium — Benzine — Glue — Salicylic Acid — Red Oxide of Mercury — Carbonate of Soda — Carbon Bisulphide — Pyrethrum. IN ITALY (page 53). Early Applications — Adoption of French Practices. IN OTHER CONTINENTAL EUROPEAN COUNTRIES (page 53). Treatments for Oidium Tuckeri — Introduction of the Grape Downy Mildew — Adoption of French Practices — Present Methods. IN ENGLAND (page 54). Slow Adoption of the French Methods — Potassium Sulphide — Introduction of Copper Sulphate — French Journals quoted — Insecticides. IN AUSTRALASIA (page 57). Experiments with Fungicides — Introduction of French and Ameri- can Practices — Tasmanian Spraying Laws. Pages 19-58 CHAPTER III. SPRAYING IN AMERICA. IN THE UNITED STATES. Spraying for Leaf- eating Insects and the Codlin-moth (page 50). — Appearance of the Potato Bug — First use of Paris Green — First use of Paris Green for the Canker-worm — First use of Paris Green for the Codlin-moth — First use of London Purple — Introduction from England — Paris Green and London Pur- ple compared. Spraying for the Curculio (page 68) — The Arsenites and the Curculio — Discussion of the Value of Spraying for Curculio — New York Practices — Ohio Practices. xiv Contents. Other Arsenites (page 74). — Paris Purple — English Purple Poison — White Arsenic — White Arsenic and Lime. Caustic and Non-poisonous Insecticides (page 77). — Alkalies — Quassia — Pyrethrum — Kerosene — Kerosene Emulsions — Cook's Hard-soap Emulsion — Cook's Soft-soap Emulsion — Hubbard-Riley Emulsion — Kesin Soaps — Resin Washes and Compounds. History of the Fungicides (page 87). — First Materials tested — Hyposulphite of Soda — Sulphide of Lime — Sulphur — Meas- ures adopted against Grape Diseases before the Use of Copper Compounds — Publication of the French Discoveries and Recom- mendations. The Warfare against the Various Fungous Diseases (page 92). — First Formulas for the Copper Sulphate Solution, Milk of Lime, Copper Mixture of Gironde, Podechard's Powder, Kero- sene Emulsions — Early Treatments of Grapes with Copper Fungicides — Tests of Fungicides — Spraying in 1887, Formulas recommended and the Plants treated — Spraying in 1888 — Spraying in 1889 — General Treatment of Fruit and Nursery Stock — Combinations of Insecticides and Fungicides — Lime and Arsenites — Spraying Greenhouse Plants — Spraying during 1890 — Improvements in Fungicides — Treatments for Potatoes — Spraying during 1891 — Dilution of the Bordeaux Mixture — Tests of the Most Promising Fungicides — Spraying since 1891 — Control of Black Knot. IN CANADA (page 112). First Adoption of Methods recommended in the United States — Spraying in Ontario — History of Spraying in Nova Scotia — Canadian Publications. Pages 59-114 CHAPTER IV. THE MATERIALS AND FORMULAS USED IN SPRAYING. An Alphabetical List of the Most Important Materials used in Spraying, with Directions for their Preparation and Use. Pages 115-180 Contents. xv CHAPTER V. SPRAYING DEVICES AND MACHINERY. I. HISTORY OF SYRINGES AND PUMPS (page 181). Heath Brooms — Watering-cans — Syringes — Fountain Pumps — Garden Engines — Knapsack Tanks — French Knapsack Pumps — American Knapsack Pumps — Introduction of Barrel Pumps — Types of Barrel Pumps — Introduction of Power Sprayers — Spraying with Steam — Spraying with Gas Power — Device for Mixing Kerosene and Water. II. EVOLUTION OF NOZZLES (page 197). Three Principles the Basis of all Spray Nozzles — The Groups of Nozzles — History of Each Group — Value of the Nozzles of Each Group. III. BELLOWS AND POWDER GUNS (page 204). Hand Bellows — Power Bellows. IV. COMPARISON OF LIQUIDS AND POWDERS (page 205). Advantages of Powders — Defects of Powders — Value of Liquids. V. MERITS OF THE VARIOUS SPRAYING DEVICES (page 207). Materials used for Making Spraying Machinery — Knapsack Pumps — Hand Syringes — Bucket Pumps — Barrel Pumps — Cylinders — Pistons — Handles — Air Chambers — Agitators — Base-castings — Types of Barrel Pumps — Horizontal-acting Pumps — Spraying Rigs and Outfits — Orchard Spraying — Power Machines — Spray Nozzles for Different Purposes — Character of Sprays. Pages 181-224 CHAPTER VI. THE ACTION OF INSECTICIDES AND FUNGICIDES. The Certainty of their Action — The Time to Spray — The Manner to Spray — Insecticide defined — Fungicide defined. THE SPRAYING OF PLANTS. PART I. THE HISTORY AND PRINCIPLES OF SPRAYING. CHAPTER I. EARLY HISTORY OF LIQUID APPLICATIONS. MAN'S power over the organisms which injure cultivated plants was never so great as it is at the present time. One by one these enemies have been carefully studied, the history of their lives determined, and their habits observed. Only by understanding them thoroughly can proper steps be taken to check their ravages in the most economical and efficient man- ner ; yet it is within comparatively recent years that this first step was taken to obtain the mastery over them. Formerly, when a pest injured a plant, it was no uncommon practice to apply any remedies or materials that came to hand, regardless of their probable efficiency. It was not generally the weakest point of the organism that was assailed. In many cases it was not even the proper organism which was held responsible for the injury. Nevertheless many valuable discoveries came from these varied and desultory treatments, and some of the remedies most highly prized to-day were discovered merely by chance, not very many years ago. Present knowledge and methods of investigation, largely founded upon this experience, enable us to arrive at conclu- B 1 2 The Spraying of Plants. sions which, from the outset, are founded upon a sound and logical basis. It is fortunate that this is the case. The number of the enemies of cultivated plants is either now more numerous than formerly, or the attacks are much more energetic. It is undoubtedly true that the maladies of cultivated plants are much more widespread. This fact is mostly due to the greater food supply, and to the greater ease with which most of the injurious forms can pass from one part of the country to an- other, because the cultivated areas lie so close together. If a plant is grown to any considerable extent, it is easy for its ene- mies to spread over the entire region in which it is cultivated. Physical barriers are almost without value in checking this spreading of disease. The ocean is only a partial exception, since such close means of communication have been established between all parts of the globe that this obstacle is now of little avail. Some diseases have not yet been able to overpass it, but as it has proved of little hindrance in so many cases, it is probable that ultimately the enemies and diseases of plants will be as widespread as are the plants upon which they flourish. Weedy plants, insects, and possibly also fungi, are frequently more destructive in a new country than in their old home. They are freed from the enemies or conditions which formerly kept them in check, and in some cases they are the cause of very serious dis- turbance, although originally they may not have been markedly destructive. Farmers and fruit growers cannot fence out the many forms of insects and fungi which live upon their crops and which are as anxious for a harvest as the grower is. It is a fight between the grower and the pest, and it must be admitted that the latter has generally had the best of the battle. The farmer has not been properly equipped. He has often had invisible foes to contend with, — foes which he did not understand, and which he could not assail. It frequently occurred that an entire crop was ruined in a day or two, and the cause remained unseen and unknown ; and even if it was visible, almost the only remedy upon which the grower could rely with certainty was mere force, first catching the pest and then destroying it. As this could be done with profit only in rare cases, it was little better than no remedy, and the general result was that the insect or the fungus obtained an ample supply of nourishment, and the Early History of Liquid Applications. 3 grower took what was left. Indeed, this method is still fol- lowed by many cultivators, but it is not the safest, nor is it the most profitable one. The best is generally the most profitable commodity, and the poorest is the least so ; and the grower of to-day has it in his power to produce the best. It rests entirely with him whether his apples shall be wormy or not, whether his trees shall retain their foliage or lose it from disease. There are few evils that aft'ect his crops which he cannot control, in many cases almost absolutely. Only a few diseases remain which still refuse to submit to treatment, but the number is rapidly decreasing, and the time will come when these also will disclose some vulnerable point which will allow of their destruction. Foremost among the operations by means of which cultivated plants are protected from their enemies, is spraying. This con- sists in throwing upon plants any fluids, or semi-fluids, in the form of a fine rain or mist. It rests upon the general principle of covering the plants, or the parts of plants to be protected, with a thin but uniform layer of some material that is poisonous, caustic, or offensive to the organism which it is desired to de- stroy. The word "spraying," as understood in this connection, has not been in general use more than ten or fifteen years, for the operation previous to this time was practiced only to a very limited extent. It was then referred to as "syringing," from the fact that hand syringes were generally used as a means of making the applications. This term is still in common use among florists and gardeners, whose daily duty it is to throw water upon their plants either for the purpose of promoting growth, or in order to keep them free from foreign matter, such as insects or dust. It is essentially a term which, in this country, is used in connection with plants grown wholly or partially in a greenhouse or in some similar structure. Spray- ing, on the other hand, is a term now used by farmers and fruit-growers to designate a similar operation, but the plants treated are grown entirely out of doors, and pure water is rarely used. The operation of both syringing and spraying is, however, the same ; namely, the throwing of liquids, more or less finely divided, upon plants or other objects. It is impossible to tell when plants were first syringed. It is very probable that the value of the operation was understood 4 The Spraying of Plants. as soon as the cultivation of plants began to attract serious attention. The immediate causes which led to the practice were undoubtedly the same as those now existing. Foliage almost invariably looks brighter and fresher when wet, and one instinctively feels that if the appearance of a plant is improved by a certain operation, the general health of the plant is improved to an equal degree. The removal of insects or any injurious substances would have a similar effect, and all good gardeners would feel a temptation to improve their plants in this simple w^ay. Insects and diseases have unquestionably troubled cultivators from the time plants were first grown. Remedies would natu- rally be sought, and it appears that these older gardeners were controlled by the same feeling which even to-day often mani- fests itself in connection with the taking of medicine : the worse the drug smells or tastes, the more good it is supposed to do. Early in the seventeenth century Parkinson advised the use of vinegar to prevent canker on trees, and the recommendation was supposed to rest upon a very firm foundation.1 One old record2 giving instructions for making liquid applications of an insecticide reads as follows : " Cantharides (Cantarides) are flies which attach themselves to the branches near the upper parts of trees, especially on the ash. They may be destroyed by pouring or throwing on the tops of the trees, by means of a small pump, water in which has been boiled some rue." Ruta graveolens is probably meant. This herb has a strong, heavy, and very disagreeable odor, and a sharp, bitter taste. If such qualities make a plant a good insecticide, rue should be one of our most valuable remedies. It seems very probable that the idea of selecting materials which are offensive to the senses was uppermost in the minds of those who first had occasion to use them, for most of the earlier substances recommended are of 1 John Parkinson, "Paradisus," The Ordering of the Orchard, Chap. viii. 550. 1629: "The canker is a shrewd disease when it happeneth to a tree; for it will eate the barke round, and so kill the very heart in a little space. It must be looked into in time before it hath runne too farre ; most men doe wholly cut away as much as is fretted with the canker, and then dresse it, or wet it with vinegar or cowes pisse, or cowes dung and urine, &c. untill it be destroyed, and after healed againe with your salve before appointed." 2 "La Theorie du Jardinage," 166, 1711. See also Deane, "The Newengland Farmer," 177-184. Early History of Liquid Applications. 5 this character. A great variety of materials must have been tested again and again by various persons independently of each other. Those materials which possessed real or imaginary reme- dial values, or which from their very nature appeared to possess them, remained in use until something that promised better could be found. Thus it came that at the close of the eigh- teenth century, and early in the nineteenth, the number of things recommended against various diseases was large, and some of the compounds possessed considerable insecticidal value. The following examples may here be cited : " In the year 1763, there appeared in the papers of Marseilles a remedy for plant-lice. The applications should be made by means of a small tin syringe having a nose pierced by about one thousand holes. The instrument is filled with water in which lime has been slaked, previously mixing with the clear liquid some bad tobacco, finely powdered ; this should be used at the rate of a handful to two liters of the liquid. The trees are syringed with the mixture, and although the foliage remains uninjured the pests are destroyed. But after four or five days the trees should be again syringed, using clear water." l " But many of the plant-lice may be destroyed by passing the leaves upon which they are found between two sponges wet with tobacco water. Ground tobacco powder spread upon the insects will kill them instantly. One may also use with it the water of slaked lime or of strong soap, soot, sage, hyssop, worm- wood, and other bitter or strong-smelling herbs. Soot, lime, and soap have the disadvantage of staining the leaves, fruits, and the plants to which they are applied. Tobacco and worm- wood leave small particles upon the portions treated. Other materials are often without value. Tansy, hellebore, rue, leek, bitter gourd, and long pepper have the disadvantages men- tioned above. Petroleum, turpentine, and other oils are also recommended ; but care must be taken in their use, since they also act upon the plants, making them sick or even killing them." 2 " First wet the trees infested with lice, then rub flowers of sulphur upon the insects and it will cause them all to burst."8 1J. A. E. Goeze, " Geschichte einiger schadlichen Insecten." Leipzig, 1787, 166. 2 Ibid. 164, s Ibid. 168. 6 The Spraying of Plants. Forsyth in 1791, * gave directions for the preparation of a com- pound which became generally known as "Forsyth's Composi- tion." The ingredients were apparently standard remedies at this time, and they persisted long after his composition went out of use. It was made as follows : "Take one bushel fresh cow dung, one-half bushel lime rub- bish from old buildings, one-half bushel wood ashes, one-six- teenth bushel pit or river sand. The last three are to be sifted fine before they are mixed. Then work them well together with a spade, and afterward with a wooden beater until the stuff is very smooth, like fine plaster used for the ceilings of rooms." Soap-suds or urine was used to make the composition of the consistency of plaster or paint. After being applied it was covered with a sifting of powder made of " dry powder of wood ashes, mixed with the sixth part of the same quantity of the ashes of burnt bones." This composition was recommended to cure disease, defects, and injuries of plants. It was held to be particularly valuable in promoting the healing of wounds, and was commonly used to fill cavities in trees. Early in the history of the treatment of plant diseases, paints and washes were in general use. They were applied by means of brushes, or the plants were actually washed with a rag or sponge, so that they were very thoroughly cleaned. This practice is by no means out of date, for it is still one of the regular duties in good greenhouse management to wash many of the plants in order to keep the foliage clean and healthy. Soap or some similar substance is still generally added to the water, as was formerly done. This alkali could always be readily obtained, and as it possesses decided merit as a destroyer of certain in- sects, it was at a very early day regarded as a valuable remedy. We have another interesting note in the following extract in which the destruction of the canker-worm is desired : 2 " There are several experiments I could wish to have tried, for subduing these insects : Such as burning brimstone under the trees in a calm time ; — or piling dry ashes, or dry, loose 1 Oath regarding the correctness of the directions was made at the Land Revenue Office, in Scotland Yard, the eleventh day of May, 1791. 2 Samuel Deane, D.D. (vice-president of Bowdoin College), "The Newengland Farmer, or Georgical Dictionary," second edition, 1797. Early History of Liquid Applications. 7 sand round the roots of trees in the spring; — or throwing powdered quicklime, or soot, over the trees when they are wet; — or sprinkling them, about the beginning of June, with sea water, or water in which wormwood, or walnut leaves, have been boiled; — or with an infusion of elder, from which I should entertain some hope of success. The liquid may be safely applied to all the parts of a tree by a large wooden syr- inge, or squirt. " I should suppose that the best time for making trial of these methods would be soon after the worms are hatched : for at that stage of their existence they are tender, and the more easily killed. Sometimes a frost happening at this season has destroyed them. This I am told was the case in some places in the year 1794." Forsyth l recommended the following mixture for the de- struction of aphis : Unslaked lime 2 peck. Water 32 gallons. Allow this to stand three or four days, stirring two or three times per day. It was applied by means of a syringe. He recommended 2 the same mixture for the destruction of acarus, or red spider, but said that pure water would also answer the purpose. For plants in hothouses the use of pure water alone was advised. Against insects on melons, however, he said 3 that the plants should first be washed with water, and then again washed with a mixture of urine and soap-suds, using a rag. It is also stated4 that several English nurserymen used train- [whale-] oil against coccus, or scale insects on plants. It was applied with a brush, but the author claims that it was not an efficient remedy. Nevertheless it was extensively used in some parts of England. During the early years of this century a great many sub- stances were recommended both in this country and in Europe for the destruction of the enemies of cultivated plants. Mention5 is made of the following articles which were to 1 William Forsyth, " A Treatise on Culture and Management of Fruit Trees," American edition edited by William Cobbett, 1802, 173. 2 Ibid. 174. » Ibid. 176. * Ibid. 179. 6 J. Thacher, M.D., " American Orchardist," 1822, 104. 8 The Spraying of Plants. be used against the apple-tree borer, an insect that is desig- nated as a " pernicious reptile " by the author. After digging out the borer, fill the cavity about the base of the tree with " flax rubbish, sea-weed, ashes, lime, sea-shells, sea-sand, mortar rubbish, clay, tanner's bark, leather scraps, etc." I can find no record of careful experiments having been made with these articles, and it is not improbable that some of them were recommended without actual trial, as is sometimes done even to this day, simply on the ground that the remedy "ought" to be of value. It is also stated,1 quoting from the " Massachu- setts Agricultural Reports," that Josiah Knapp, of Boston, in 1814, used air-slaked lime with success against the canker-worm. He applied it thickly about the base of the tree. Later experi- ments have shown that this is of little benefit in checking the ravages of the insect. The use of air-slaked lime is said 2 to have been successful in the destruction of slugs found on the foli- age of fruit trees, and this is still one of the best remedies we possess. Tar water also proved to have the power of instantly killing the slugs with which it came in contact. It was pre- pared by pouring water on tar and allowing it to stand for two or three days. This gave a strong infusion and was said to be very effective. Several remedies against caterpillars are also mentioned.3 " It is asserted " that spirits of turpentine, or common fish-oil, has the power of penetrating through the web made by these insects and they are killed when the liquid comes in contact with their bodies. Mr. Yates, of Albany, N.Y., made a mix- ture which well illustrates the variety of materials used during this period : Wormwood 1 handful. Rue 1 Virginia tobacco 2 handfuls. Water 2 pailfuls. Boil the herbs in the water for half an hour, strain the liquid, and it is then ready to be applied. Yates also said that if sufficient tobacco is used alone, it will answer the same pur- pose as the above, but not so well. 1 J. Thacher, M.D., " American Orchardist," 1822, 92. » Ibid. 107. » Ibid. 96. Early History of Liquid Applications. 9 Reference is also made 1 to some experiments of E. Perley to combat scale insects on trees. He found, after trying many sub- stances, that the most effectual way of removing scale insects from trees was to wash them with lye, or brine. Lime could be used with the lye to advantage. The brine was made by using Common salt 1 quart. Water 2 gallons. This could be applied as soon as the salt was entirely dissolved. Thacher2 regarded train-oil as a very powerful insecticide against lice, but discouraged its use on account of its glutinous character, it being on this account harmful to trees. Clay paint was perhaps one of the first remedies to be ap- plied to plants. Several factors would encourage its use ; among others may be mentioned the ease of its preparation, its cheap- ness, and its adhesive properties. When properly used it forms a thin, dense coating over the parts to which it is applied, and it has the appearance of granting almost perfect protection to the part covered. The Caledonian Horticultural Society, of Scotland, recommended 3 its use, and, in fact, its application has been very generally advised. It has also formed the basis of many mixtures and only with the appearance of the remedies now in common use has it fallen from favor. Only the purest clay obtainable was selected, and it was generally strained so that the coarser particles might be removed. A solution which appears to have been in common use for the destruction of bed-bugs was also said4 to be valuable as a remedy for canker. " Canker " is an indefinite term which was employed to denote almost any disease of the stems or trunks of plants, whose origin was not understood ; the injury may have been caused by insects or by fungi, or any of several other causes. Whenever death and decay overtook any part of the stem, it was generally termed canker. The solution which would cure or check the disease was made by taking Corrosive sublimate 1 drachm. Spirits (alcohol) 1 gill. Soft water 4 quarts. 1 J. Thacher, M.D., "American Orchardist," 1822, 109. 2 Ibid. 108. s Ibid, second edition, 1825, 79. 4 "The Practical American Gardener," Baltimore, 1822, 170. 10 The Spraying of Plants. The corrosive sublimate was first dissolved in the spirits, and then this solution was added to the water. It was said to kill the eggs as well as the insects with which it came in con- tact ; and although long in use it still stands as one of the most valuable agents for the destruction of some insects which are not closely connected with horticultural products. It also possesses1 the power of destroying the "brown turtle [scale] insect, white scaly coccus, pine bug [mealy-bug?], and red spider." A decoction of tobacco was pronounced to be excel- lent for the removal of aphis, thrips, and wood-lice. Although fungous diseases are rarely mentioned in these early writings, their suppression was nevertheless attempted. John Robertson, in a paper read Nov. 20, 1821, before the London Horticultural Society,2 said sulphur was the only specific remedy that could be named for the treatment of mildew on peaches. It should be mixed with soap-suds and then be applied by dash- ing it violently against the trees by means of a rose syringe. It was necessary to sprinkle all parts of the tree with the mixture to be certain of success. Sulphur is to-day one of our standard remedies against such mildews, and it seems that no other sub- stance will soon supersede it. William Cobbett mentions 3 some instructions for the treat- ment of the cotton blight (woolly aphis) which, if well carried out, would certainly dislodge the pest. He directs that where these insects are found, to wash " the place well with some- thing strong, such as tobacco juice. The potato, which some people look upon as so nutritious, very nearly poisons the water in which it is boiled ; and an Irish gentleman once told me that that wrater would cure the cotton blight. Rubbing the part with mercurial ointment will certainly do it." The idea that " something strong " was necessary to dislodge the enemy was still, apparently, the leading thought, and nearly everything that could be said to possess this desired quality was probably given a chance to prove its merits at one time or another. Thomas Fessenden gives4 an interesting list of a few of the materials which were supposed to possess the 1 "The Practical American Gardener," Baltimore, 1822, 397. 2 Trans. London Hort. Soc., Vols. i.-v. 1824, 178. 8 Cobbett, "The English Gardener," 1829, first English edition, 289. * Fessenden, "New American Gardener," sixth edition, 1832, 169. Early History of Liquid Applications. 11 strength necessary to overcome the organism against which they were applied. He writes as follows : "Insects may be annoyed, and oftentimes their complete destruction effected, by sprinkling over them, by means of a syringe, watering-pot, or garden engine, simple water, soap- suds, tobacco water, decoctions of elder, — especially the dwarf kind, — of walnut leaves, bitter and acrid herbs, pepper, lye of wood ashes, or solutions of pot and pearl ashes, water impreg- nated with salt, tar, turpentine, etc. ; or they may be dusted with sulphur, quicklime, and other acrid substances." An- other article, one mentioned by Lindley,1 is vinegar, and he says that it is of considerable value for destroying insects. With such a battery of powerful materials directed against them, it is a wonder that so many insects we now have to con- tend with should still exist. The very number of the materials named is an indication of weakness ; for if any of them had really possessed very decided merit, there would have been no necessity for the existence of the rest. Some of them are really valuable, and are in use at the present time, yet it is true that we are still on the lookout for something which is superior to the remedies now at hand. The value of hot water as an insecticide has long been known. Fessenden quotes2 London as saying: "Saline sub- stances mixed with water are injurious to most insects with tender skins, as worms and slugs ; and hot water, when it can be applied without injuring vegetation, is equally, if not more powerfully, injurious. Water heated to 120 or 130 degrees will not injure plants whose leaves are expanded and in some degree hardened ; and water at 200 degrees or upwards may be poured over leafless plants." In a later work,3 London says : "Mr. Swainson advises for the destruction of the aphis 'the application of warm water, sufficiently hot to destroy aphis without injuring the trees : more will be thus destroyed than either by repeated application of the syringe or by the use of tobacco water. . . . Two or three applications of warm water will destroy nearly all the insects.'" The remedy was also frequently mentioned in horticultural journals. 1 Lindley, " Guide to the Orchard and Kitchen Garden," 1831, 509. 2 Fessenden, "New American Gardener," sixth edition, 1832, 169. 8 " London's Encyclopedia of Gardening," 1878, 795. 12 The Spraying of Plants. Dr. William Kenrick l speaks of aloes and cayenne pepper, among other materials, as being effective in the treatment of aphis, but their use never became very general. He also gives 2 a formula for the destruction of a white, mealy insect : Quicklime 2 peck. Flowers of sulphur £ pound. Lampblack I " Mix all in as much boiling water as will make a thick paste, and apply warm. The lime and the sulphur are probably the most active portions of the mixture. Although lampblack is here mixed with them, these two substances, when used to- gether in water, already formed one of the most important and valuable remedies in use against the various mildews which attack plants. The same writer gives 3 the following formula, in which sulphur and quicklime are recommended for checking mildew on grapes : Sulphur \ pint. Quicklime piece size of the fist. Water (boiling) 2 gallons. When cool, dilute with cold water, and allow the solid mate- rial to settle. Then draw off the clear liquid, and pour it into a barrel. The barrel is then filled with water, and the mixture is ready for use. A modification of this formula eventually came to be a standard preparation for the treatment of mil- dews; but during this period the substances were used in varying proportions, and generally other ingredients were mixed with them. John Mearns made a composition, which was suggested to him by Thomas Andrew Knight, at that time president of the London Horticultural Society.4 In a paper read in 1835, he gave directions for making this preparation : Strongest farmyard drainage 1 gallon. Soft soap 1 pound. Flowers of brimstone " 1 William Kenrick, " The New American Orchardist," 1833. Introduction, xxxiii. 2 Ibid, xxx vi. 3 /j^. 328. * Trans. London Hort. Soc. second series, 1842, Vol. ii. 39. Early History of Liquid Applications. 13 These ingredients were well mixed together and were stirred three or four times a day. This was done for several days, and then some finely sifted quicklime was added, until the whole assumed the consistency of paint. Mearns said the farmyard drainage might be replaced by tobacco juice, and the lime by soot. This mixture was recommended for the destruction of insects. The use of pungent and acrid herbs long continued to be recommended for the same purpose. T. Bridgeman, among other remedies, speaks l of burdock leaves as being effective in preventing injury from the attacks of the "turnip and cabbage fly." He recommends preparing hogsheads full of the infusions of this and other herbs, and then sprinkling the plants with the liquor. For the annoyance or destruction of insects on fruit trees he advises the use of decoctions made of walnut leaves, as well as those of tobacco and elder; the use of pepper, soot, sulphur, and similar substances are also mentioned as having value, their action being perhaps more particularly the annoy- ance of the pest than its destruction. White hellebore was also commonly recommended as early as 1842, although it did not prove of value in the hands of all growers. It was used particularly to destroy worms on gooseberry plants, and was applied in the form of a powder or in pure water, or when mixed with soap-suds.2 It does not appear to have been used to any considerable extent in America until after the introduction of this gooseberry saw-fly, or as it is here known, the imported currant worm, which occurred sometime before 1858, at which time its presence was first noticed. Joseph Harris is said to have been the first to recom- mend the use of hellebore in America,3 after he had been using it successfully for four years. P. Barry used it mixed with water, and applied the liquid to his plants by means of a syringe, one-half pound being used in a pail of water. A rather unusual solution was used by J. Murray 4 against mildew on peach trees. He applied Sulphur 2 pounds. Alcohol 1 quart. 1 Bridgeman, "The Young Gardener's Assistant," seventh edition, 183T, 11 2 Gardeners' Chronicle, 1842, June 18, 397. 3 Country Gentleman, 1865, June 29, 413. 4 Gardeners' Chronicle, 1841, Aug. 21, 550 14 The Spraying of Plants. The trees were thoroughly painted with this when the buds were swelling. He asserts that he used the mixture for twenty years, so it must have been very effective in his hands. Nitre was also applied for mildew on roses.1 It was prepared by using Nitre 1 ounce. Water 1 gallon. In December, 1844, its use on chrysanthemums for mildew was also mentioned. On June 13, 1840, the Massachusetts Horticultural Society offered a premium for the most cheap and effective mode of destroying the rose-bug. David Haggerston, of Watertown, Mass., was awarded a premium of $120 on March 5, 1842, after his remedy had been thoroughly tested by a committee. The material which he employed was whale-oil soap, used at the rate of Whale-oil soap 2 pounds. Water 15 gallons. He said the strength of the soap varied and this would re- quire a change in the above formula in certain cases. He con- tended that this is an effectual remedy for other troublesome insects ; as the thrips or vine f retter, the aphis or plant-louse, the black fly that infests the young shoots of the cherry, the red spider, and other insects. He also asserted that it would destroy mildew on peaches, grapes, and gooseberries, if weak solutions were used. Whale-oil soap is to-day so well known and so generally used against insect enemies that it is scarcely necessary to say that many of the statements of Haggerston are just.2 Loudon has recorded 3 several interesting recipes that show how complex were many of the mixtures recommended. Some of them contained so many ingredients that it would seem as if any evil that plants are heir to would be reached by at least one of them. Nicol's recipe was thought to be particularly 1 Gardeners' Chronicle, 1844, Jan. 27, 53. > "Hist, of the Mass. Hort. Soc.," 1829-1878, 256. Country Gentleman, 1842, 134. » "Loudon' s Encyclopaedia of Gardening," 1878, 785. Early History of Liquid Applications. 15 valuable for the destruction of coccus, or scale insects ; it was made as follows : Soft soap 1 pound. Flowers of sulphur 1 " Tobacco 2 " Nux voraica 1 ounce. Soft water 4 gallons. These materials were well mixed with the water and then boiled until the amount of liquor was reduced to three gallons. It was then allowed to cool, and was ready for use. Plants which were not in active growth, and whose foliage was not too tender, were dipped into the mixture. For overhead syringing, the liquid was diluted one-third with water. Hamilton's recipe is also given : l Sulphur 8 ounces. Scotch snuff 8 " Hellebore powder (> " Nux vomica 6 " Soft soap 6 " Cayenne pepper 1 ounce. Tobacco liquor 1 quart. Water (boiling) 1 gallon. Stir and render as fine as possible, and then strain through a rough cloth. Hamilton did not appear to feel very confident of the action of even this array of death-dealing matter, so he advised in addition that the plants be washed with it, and the insects removed while washing. When so used it would doubt- less act as a specific. The recipe is also interesting from the fact that it contains hellebore as one of the ingredients ; for at that time the use of this poison was probably somewhat limited. The insecticidal value of decoctions made of the wood of quassia was also known to a limited extent; but the material has been more widely recommended than used. Hemery, a French nurseryman, made a compound 2 which he said would destroy mildew on peaches if only one application were made. It contained some materials which unquestionably 1 " London's Encyclopaedia of Gardening," 1878, 785, quoted from Speechly, "Treatise on the Pine," 1779, 60. 2 Revue fforlicole, 1849, Sept. 15, 360. 16 The Spraying of Plants. possessed " strength," but whether best adapted for the purpose designed may be open to doubt : (a) Aconite branches and tubercles 1 kilogram. Water 4 liters. (b) Pigeon dung 25 " Urine 1 hectoliter. Mixture (&) was allowed to ferment forty-eight hours, and infusion (a) was added only just before the mixture was used. The applications should be made in April. The most important and probably the most effective form in which sulphur was used was the solution known as the "Grison liquid " (eau Orison}. It was also called the poly- or the hydro- sulphur of Grison ; it is still in use, although not so commonly as heretofore. Grison was head gardener of the vegetable houses (serres du potager} at Versailles, France, and in 1851 he first made the solution. He used l Flowers of sulphur 500 grams. Freshly slaked lime 500 " Water 3 liters. Boil the above for ten minutes, allow the mixture to settle, and then draw off the clear liquid. Keep this in bottles and before using add one hundred parts of water to one part of the liquid. Apply with a syringe. This solution is excellent for all surface mildews, and three applications are sufficient to pro- tect foliage. Later the quantity of sulphur and of lime was reduced one-half and it is one of the few early fungicidal prepa- rations still in use. An Englishman claims 2 to have used a similar preparation as early as 1845, using one part of sulphur, one part of lime, and one hundred parts of water. Grison, however, appears to have been entirely independent in the manufacture of his preparation, and it soon became much better known than the other. Lime wash was recommended in America against curculio of plums in 1850. Lawrence Young, of Louisville, Ky., seems to have been one of the first to try this remedy, and it was ap- parently successful.3 " It consists simply of covering the young 1 Revue Hortieole, 1852, May 1, 168. 2 Tuck, Gard. Chron. 1852, July 27, 419. 3 Country Gentleman, 1850, 333. Early History of Liquid Applications. 17 fruit, as soon as danger is apprehended, with a coating of thin lime wash, considerably more dilute than the mixture em- ployed in white-washing." The use of quassia chips was adopted in America soon after hellebore became known. In 1855 the material was recom- mended as a remedy for aphis, being prepared by boiling Quassia chips 1 pound. Water 8 gallons. The liquid was boiled until the decoction had been reduced to six gallons.1 An interesting article by W. F. Radclyffe appeared in one of the English journals2 in 1861. The writer, knowing the value of copper sulphate when used upon smutty seed-wheat, reasoned that the rose mildew, being also a fungous trouble, should likewise yield to treatment by this chemical. He there- fore applied a solution of two ounces of blue vitriol dissolved in a " stable bucket " of water to live plants by means of a fine spout, and entirely freed his plants from the disease. The statement was also made that weaker solutions would be tried the following year. A few weeks later a note appeared in the same journal which warned growers against the use of the sul- phate of copper, as it would kill roses if it came in contact with their roots. No further mention of the remedy was made, and even the following year brought no account of any experiments made by Radclyffe. What millions might have been saved had this important work been carried only a little further ! But the old remedies continued to be used until about 1870 ; insects and fungi were treated practically the same in Europe and in America, and changes of only minor importance were made. The Americans profited very largely from the experience of European gardeners, but a few new methods of treatment also arose in this country. It could not be otherwise, for different enemies had to be dealt with, and these required different treat- ments. But these variations were comparatively slight, and the remedies used in the first half of the century were more or less common as late as 1880. Sulphur in some form was every- 1 Michigan Farmer. Cited in Country Gentleman, 1855, April 12, 235. 2 Gard. Chron. 1861, Nov. 2, 967. 18 The Spraying of Plants. where the standard remedy for mildews, and when this failed, growers were at a loss to apply anything more efficient. The best insecticides were the various forms of soap, tobacco, quassia chips, carbolic acid, and hellebore, although the last was a com- paratively new remedy. Kerosene was also used in America to a limited extent. With these materials gardeners and fruit growers managed, as a rule, to produce good crops. But a change was to come. In America it was brought about by insects ; these became so abundant and began to do so much damage in districts that before had not suffered seriously, that new remedial measures were demanded. A new insect, the potato beetle, was introduced from the far West, and this threat- ened to be even more destructive than those which were in- digenous to the East. In Europe the revolution was brought about by fungi, but not by the European types. They came from America, and have shown, in southern Europe particularly, the same push and energy which is everywhere recognized as characteristic of the American. And so it came that while the growers in France were combatting fungi, those in America were contend- ing against insects, and a great difference soon arose in the methods of treatment adopted. It was a veritable revolution ; for old remedies were obliged to give way to new ones, and established methods to those but little tried. Indeed, the change marks an epoch in the history of the cultivation of plants. CHAPTER II. SPRAYING IN FOREIGN COUNTRIES. I. IN FRANCE. Discursive Trials of Fungicides. No important changes took place in the materials used by the French for the destruction of fungi and insects until about the year 1882. The use of chemicals in place of the substances which appeal strongly to the senses had increased, for an occa- sional mention is made regarding the more or less successful trial of some new material of this character. Gironard1 says that in 1862 the idea occurred to him to use from two to four grams of acetate of potassium in one liter of water for the pre- vention of mildew on grapes. The results were very marked, and in 1863 the vines were productive directly in proportion to the amounts of the chemical applied. But this substance did not come into general use, and it was not until the value of the compounds of copper became known that any permanent advances were made. Soon after the appearance in France of the downy mildew (Peronospora viticola) the necessity for a more energetic fungi- cide than sulphur became evident. Sulphur as then used seemed to be entirely without effect in checking the progress of this disease. The mildew was first discovered in France in 1878. 2 Millardet saw it in September of that year upon some American grape seedlings growing in the nursery of the Societe d'Agricul- ture de la Gironde, and Plachon at the same time recognized it 1 Bulletin de la Societe d"1 Horticulture d'Eure-et-Loir, 186S, No. 13, January, 270. 2 Jour. d'Ag. Prat. 1881, Feb. 10, 192. 19 20 The Spraying of Plants. on the leaves of Jacquez grapes at Coutras and also received it from various departments of Lot-et-Garonne, and of Rhone. The disease spread rapidly and was so destructive that in 1882 the fruit in many vineyards was almost entirely destroyed. The climate of France appears to be peculiarly adapted to the growth of this mildew, which nourishes as well upon the varie- ties of Vitis vinifera as upon our American species. In moist seasons it is fully as energetic as in America, or even more so. The leaves fall from the vines, and the grapes are thus prevented from ripening properly. Even in cases in which the vines do not lose all their foliage, a partial reduction is sufficient to de- crease the amount of sugar in the grapes to such an extent that their value for wine is very greatly lessened. Many growers did not at first realize the seriousness of this disease. In some vineyards it even obtained a firm foothold without being noticed, for the portions of the fungus which are on the exterior of the leaves are borne on the under side. When, however, it became established in a certain district, all doubts regarding its serious- ness vanished, and the vineyardists found themselves confronted by a disease which not only threatened to destroy their vines, but which gave unmistakable proof of its power to do so. The remedies in general use for controlling the European surface mildew (Oidium Tucker i) proved to be of little value against this new foe. Spraying with milk of lime was recom- mended and very thoroughly tried, but it did not give such good results in France as were reported from Italy. The milk of lime was used with good results against the oidium of the grape by Professor Keller even before 1852. l In 1881 Professor Garovaglio, director of the cryptogamic laboratory at Pavie, used it with fairly good success against the peronospora, but his statement of this work, although apparently of the greatest im- portance, received no attention from Italian vineyardists. It was not until 1883, when the work of the agricultural school at Conegliano, Italy, became known, that the remedy was generally adopted. Many growers in northern Italy, especially the Bel- lussi Brothers, near Conegliano, were particularly successful, and so much confidence was placed in their method of control- ling the mildew that the minister of agriculture, in a circular published in 1885 recommended its general adoption. During 1 Cerlettie Cuboni, Annali di Agricoltura, 18S6, 20. Spraying in Foreign Countries. 21 this same year Cerletti published 1 an important article in which he announced that the peronospora could be effectually com- bated by the use of the milk of lime. The mixture was made by slaking 3 kilos of quicklime in 100 liters of water, first con- verting the lime into a fine powder, by partially slaking it, and then adding the remainder of the water.2 Powders were very extensively tried in France. Their use was undoubtedly suggested by the fact that sulphur had been applied in the form of a powder for a great many years. There was at this time no apparatus particularly adapted to the application of liquids, but such was riot the case- with powders. As early as 1881 3 Professor Millardet, of the Faculty of Sciences of Bor- deaux, used the sulphate of iron in powdered form in connec- tion with sulphur and also with plaster. He reported to Mme. Ponsot (who suggested this practice, and with whom he carried on the work) that 4 kilos4 of sulphate of iron mixed with 20 kilos of plaster had stopped the mildew. J. Laure,5 an engineer at Apt (Vaucluse), had for several years made a study of a certain ore of sulphur, called " Souf res des Tapets." This mineral contained various substances besides sulphur, and after having been treated so that it contained more or less of the sulphate of iron it was sold under the name of "Fungivore." It was highly recommended against attacks of anthracnose, and was also very effective in checking the oidium of the vine. From three to six applications were necessary to protect the plant well. It was used to a considerable extent, but this powder, as well as the many others which were sold, did not equal the liquid applications in efficiency. (See page 32 for a more complete discussion of the powders which came into use as fungicides.) Other fungous diseases than those of the grape were now attracting attention. Paul Oliver said6 that for several years pears had suffered from the attacks of a fungus which pro- 1 Rivista di Viticoltura, 1885, Aug. 30. 2 Pinolini, " Le Crittogame," 1888, 30 et tseq. 3 Jour. d'Ag. Prat. 1883, April 19, 553. 4 One kilogram is equal to 2.2 pounds. Since the metric system is the one used by the large majority of the experimenters of continental Europe, the system will be retained in this portion of the work. For a complete scheme of the weights and measures of the metric system, as well as their equivalents, see Appendix. » Jour. d'Ag. Prat. 1883, April 19, 554. « Ibid. 1881, July 7, 20. 22 The Spraying of Plants. duced black, velvety spots upon the foliage, and in 1880 it also deformed the fruit to a considerable extent. The cause of the injury was attributed by Prillieux,1 the inspector-general of Agricultural Education, to Fusiclndium pyrinum ( Cladoxporium (lendriticum, Walr.), and a description of the fungus was pub- lished. Paul Oliver2 made some experiments which were de- signed to throw light upon the best method of destroying the spores of the parasite. The materials used were, (1) pure water ; (2) water acidulated with one-twentieth its amount of sulphuric acid; (o) a 33£ per cent solution of the sulphate of iron ; (4) a 16| per cent solution of the sulphate of copper. He advised the use of the last in rainy weather, but during dry weather either the second or the third would prove effective. Oliver further states that he succeeded in killing the spores of F. pyrinum with an 8 per cent solution3 of copper sulphate, and that he sprayed his trees with a 10 per cent solution during the winter of 1882-3. This discovery — that the salts of copper would prevent the germination of the spores of fungi — was by no means new. As early as 1807, Benedict Prevost gave * an account of the method by which he prevented the germination of the spores of a fun- gous disease commonly known as " Carie," or " Charbon " (smut), of corn. His statement regarding the result of his experiments is as follows : " The amount of sulphate of copper really necessary to give to water the power of preventing the germination of the spores in a low temperature does not amount to ¥ooW of its weight, and To0-