The most important additions to the list of insecticides made in France were American remedies. During 1884, Professor C. V. Riley of the Agricultural Department at Washington, visited France, and in an address delivered before the Société Centrale d'Agriculture de l'Hérault, June 30, 1884, he spoke of the emulsions of kerosene with milk or soap, of the arsenites as used in America, and of pyrethrum.1 The formula for making the first preparation was as follows: Petroleum Water 8 liters. .175 grams. 4 liters. Dilute with water as experience may suggest. The directions were slightly modified in later years, but on the whole this remedy was soon widely used in France. Although the attention of experimenters was more particularly directed towards the fungous diseases of plants, various other insecticides were tested. For large caterpillars, Leizour advised the use of The soap and the sulphide of potassium are separately dissolved in a few liters of water. The two are mixed, and the remaining amount of water is added immediately before the applications are made. A remedy supposed to be particularly valuable for the destruction for the woolly aphis was made by taking, This was to be applied in March and April. A decoction of datura plants, when used with the sulphate of iron, was also recommended, as well as amylic alcohol and soap water.2 Another preparation of a more complicated character was recommended for the same insects. Chemicals having proved 1 Messager Agricole, 1884, July 10, 255. 2 Jour. d'Ag. Prat. 1890, June 19, 901. so valuable in the destruction of fungi, it was probably supposed that some material could be found which would bear the same relation to insects that the copper compounds do to the mildew. The idea was certainly a good one, but since no such substance at that time in general use by the French has remained as a leading remedy, their new introductions appear to have been at least only partially successful. The use of the following formula was advised: The above was diluted with 30 parts of water when applied. The cochylis (Cochylis roserana) is an insect which often does much damage in French vineyards, as it feeds upon the leaves and the inner portions of the berries. One preparation which was recommended1 for its destruction is made as follows: The last two ingredients form an oleo-sulphide of carbon, 10 liters of which are poured into each hectoliter of the carbonate of soda solution, thus forming an emulsion of carbon bisulphide. Quantin, director of the agricultural laboratory of Loiret, said he had freed his vines of the cochylis by means of the above remedy. A. Lesne 2 tried experiments with eighty preparations for the destruction of the cochylis. His work showed that a preparation of pyrethrum and soap gave the best results. He had it tested by thirty-seven vineyardists and most of them reported favorably regarding it. The ingredients used were The pyrethrum is added to the soap solution and the two are well stirred; 90 liters of cold water are then put in, and the mixture is ready for use. Many other preparations were made, but they were composed principally of the ingredients mentioned above, although the combinations and the proportions varied more or less; petroleum, however, is very often mentioned in them. The arsenites have not as yet been applied to any considerable extent, and the use of pyrethrum has been limited, yet the time may come when the former will be applied as freely as is now done in America. II. IN ITALY. Italian horticulturists have followed the French so closely that little can be said concerning the discovery of new methods in Italy. Milk of lime gave great promise during the first year of the invasion of the downy mildew, as already mentioned on page 20. But this substance was soon replaced by the copper compounds, and the French methods were adopted almost as early as they were in France. At present, the Bordeaux mixture is also the standard fungicide in Italy, and sprayed vines can everywhere be seen during the summer months. Italian chemists have, however, taken the lead in the study of the various materials used as fungicides, and the principal results of their work of this nature will be found in the chapter treating of the materials and formulas used in spraying. III. IN OTHER CONTINENTAL EUROPEAN COUNTRIES. The European mildew of the grape (Oidium Tuckeri) is said 1 to have been introduced from England into Germany about forty years ago, and from there it spread to France, the Tyrol, and Italy, causing much damage. The remedy generally adopted was to apply flowers of sulphur upon the fruit and foliage, and this proved effectual in preventing its ravages. The downy mildew, however, was introduced into Europe by way of southern France. Although it was rapidly disseminated, 1 Held, "Weinbau," 1894, 125. the proper remedies for its control were soon found, and as the disease became more widely distributed, the best remedies discovered in the region first attacked were adopted by the newly infected districts, with practically no modification. It has thus been brought about that the Bordeaux mixture, the ammoniacal solution of copper carbonate, the eau céleste, and solutions of copper sulphate, have become standard remedies in those countries which have been last to suffer from the imported American diseases. These fungicides are generally applied as in France. In Germany, however, care is taken that no applications are made during the blossoming period, and there seem to be good reasons for the practice. Later applications are made often enough to prevent injury from fungi, the numbers varying from two to five, three being more commonly made. Anthracnose of the vine is treated as in France, and appears to be held under control without much difficulty. Confidence has thus again been restored where not more than ten years ago there prevailed the greatest anxiety regarding the future of the grape industry. IV. IN ENGLAND. The English have been slow to adopt new remedies for plant diseases. While French growers were struggling to overcome the downy mildew of the grape and the rot of potatoes, British gardeners were practically helpless in dealing with them. Even after success had rewarded their southern neighbors, the new methods were but slowly adopted in England. The horticultural journals of that country, on the contrary, were quick to see the value of the work that was being done, and the French recommendations were repeatedly published. The first account appears to have been given in The Gardeners' Chronicle.1 This was a translation of a report made by Prillieux, inspector-general of agricultural education, to the minister of agriculture of France, regarding the value of a mixture of copper sulphate and lime against the mildew of the vine. The account contains a brief history of the work done in the Médoc, and also mentions the names of the men who were most prominently connected with it. 1 Gard. Chron. 1885, Nov. 7, 594. The sulphide of potassium was at one time very highly recommended in England. It was first successfully applied by Edmund Tonks.1 He used one-half ounce in a pint of water, and it proved to be very effective in controlling the mildew of roses. This soon became one of the best known remedies in England, and may have been influential in delaying the adoption of French practices. A note published in 1887 2 says that "the sulphate of copper is being used largely in America and France against mildew on vines. It is even suggested as a remedy for potato mildew, but as this grows in the interior of the plant it is difficult to see that it can effect much good. Amongst several methods of applying the copper solution, the simplest is to dissolve 1 pound of the pure sulphate in 25 gallons of water. Spray the vines with a force-pump with a nozzle of fine aperture. The addition of 1 pint of ammonia to the above solution adds to the effect. By ammonia we presume a solution of the carbonate is intended." The progress made in France was carefully watched by some of the English journals. The results of the more important experiments were published, and English gardeners were not wanting in information regarding the value of the copper compounds. A few of the more important articles may here be mentioned. The Gardeners' Chronicle was especially active in this respect, and in 1888 3 it gave an account of the method of making the Bordeaux mixture as recommended by Prillieux. Three weeks later it speaks of the experiments of Prillieux regarding the treatment of potatoes for the blight. These experiments were very successful, and if the methods had been adopted in England great losses would have been prevented. During January of the following year 5 there appeared a translation of an article in the Revue Horticole regarding the proper manufacture and use of the sulphate of copper and lime mixture. Several such translations were made during 1890, but these were apparently not heeded until 1891,6 when the Royal Agricultural Society of England conducted some experiments for the prevention of blight upon potatoes. These experiments are probably 1 Gard. Chron. 1885, Feb. 28, 276. 2 Ibid. 1887, Aug. 6, 166. 8 Ibid. 1888, Sept. 1, 244. 4 Ibid. Sept. 22, 332. |
