Spraying is the art of protecting cultivated plants from insect enemies and vegetable parasites by covering them with a material which shall have a toxic or physically injurious effect upon the animal or vegetable organism.

Historical Sketch

The history of spraying is interesting. The story of its progress in America diners in details From the history of its development in Europe, but the main features in each country are very similar. In both places, insect enemies made the first draft on the ingenuity of man in devising methods by which to hold them in check. Vegetable parasites were studied afterward. It is a curious fact that, in the case of both insects and fungi, in America, some of the most injurious forms came from Europe and were the means of directing attention to wholesale methods of destroying them. Some of these enemies, comparatively harmless in their native home, like the currant-worm and codlin-moth, have done more to forward spraying methods in the United States than anything else.

The first insecticides used in America, as well as in Europe, were not of a poisonous nature. They were substances that had an injurious effect on the body of the insect. These were of two kinds, mainly: infusions which were astringent, and caustic substances which burned the tissues. Tobacco water and alkaline washes have been used for many years. One of the first poisons to be used was white hellebore. The employment of arsenical poisons may be said to belong to America, and even at the present time has small place in the economy of fruit-growing in Europe. The widespread use of arsenical poisons is largely due to the influence of the incursion of the potato-bug. There are no reliable records which give us the exact date of the first use of paris green. It probably occurred about 1865 or 1866. However, towards 1870 paris green was used very generally throughout the western region in which the potato-bug first appeared. At this time it was applied almost exclusively in the dry form diluted with gypsum or flour. From potato to cotton, tobacco and finally to fruit trees, is the development of this poison for destroying leaf-eating insects.

So far as records are available, it appears that fruit trees were first sprayed with paris green between 1873 and 1875. Among pioneer sprayers, should be mentioned the names of C. V. Riley, United States Entomologist; LeBarron, State Entomologist of Illinois; William Saunders, London, Ontario, Can.; J. S. Woodward, Lockport, N. Y.; T. G. Yeomans & Sons, Walworth, N. Y.; A. J. Cook, Agricultural College, Mich.

Following paris green came london purple, then white arsenic, and later arsenate of lead. Since that time many different forms of arsenical poisons have been compounded, offered to the public and frequently used. A few years ago paris green was used extensively, but its popularity now is decreasing, probably because it contains a large percentage of soluble arsenic, which increases the danger of foliage injury. London purple has been largely dropped by fruit-growers, owing to its variable quality. White arsenic, in combination with soda and with lime, forms a reliable insecticide and is used by some growers, especially those who make a practice of preparing the home-made solutions. Arsenate of lead is the insecticide used most widely by the growers at the present time. It possesses several advantages, the more important of which are a small percentage of soluble arsenic and better sticking qualities.

The sucking insects presented a more difficult problem of control than the biting insects, and a longer time elapsed before effective methods had been devised for treatment. One of the first efficient sprays for these insects was kerosene in the form of a soap-and-water emulsion, which was recommended by Riley and Hubbard. Among the earlier sprays for these insects was also tobacco and whale-oil soaps, both of which are used rather widely at the present time. Later the miscible oils were introduced. These proved to be very effective and are still used. The most important step in the control of the sucking insects is marked by the introduction of the lime-sulfur wash. This mixture, which was originally developed as a dip for the control of scab on sheep, was first used as an insecticide on fruit trees in 1886 by F. Dusey, of Fresno, California. The wash proved very efficient and with modifications came quickly into favor. Now lime-sulfur is the leading insecticide for the control of certain scale insects and also, in a more dilute form, the leading fungicide for the more troublesome diseases of the apple.

Apple cluster ready for the spray. The blossoms have not yet opened.

Fig. 1326. Apple cluster ready for the spray. The blossoms have not yet opened.

Splint broom for applying spray. An early device.

Fig. 1327. Splint broom for applying spray. An early device.

The treatment of fungous diseases of plants by liquid applications began with the discovery of bordeaux mixture. Early in the 1880's, diseases of grape-vines threatened the extinction of French vineyards. The situation engaged the attention of French investigators. Notable among them were A. Millardet and his co-workers of the Academy of Science, Bordeaux, France. He, with others, discovered partly by accident and partly by experiment that solutions of copper prevented the development of downy mildew. After much experimentation, "bouillie Bordellaise" was found to be effective in preventing the growth of downy mildew and other plant parasites infesting the grape in that region. The announcement was definitely made in 1885. The following year the European formula for bordeaux mixture was published in several places in the United States, and immediately there began an unparalleled period of activity in economic vegetable pathology. This mixture, though somewhat modified and developed, continues to be a leading fungicide. The value of lime-sulfur as a fungicide applied to the peach during the dormant season to control the leaf-curl has been recognized.

About 1907,

A bucket pump.

Fig. 1328. A bucket pump.

Knapsack pump.

Fig. 1329. Knapsack pump.

Cordley discovered that lime-sulfur in more dilute form may be applied to the apple and some other tree fruits in foliage without danger of foliage injury, and that in addition to being as effective as bordeaux it produces no spray injury on the fruit. Since then lime-sulfur as a fungicide has practically replaced bordeaux in the case of those fruits for which it can be used on the foliage with safety. The self-boiled lime-sulfur was developed about 1907 as a fungicide for the control of the brown rot of the peach.

The rapidity of the spread of spraying knowledge among fruit-growers is remarkable. Only a few years ago it was an unknown art by the rank and file. Today agricultural clubs and granges purchase their spraying materials by the carload direct from the manufacturer. The American farmer leads his fellow-workers in all parts of the world in the practice of spraying.