CHAPTER VII.

DISEASES, INSECTS AND SPRAYING.

IN 1886, the present author wrote as follows: "A remedy proposed of late is to syringe the trees with a mixture of Paris green and water, very early in the season, while the young apples stand erect. The poison lodges in the 'blossom end' and destroys the first brood of worms. Later, when the apples turn downward, the poison is washed out by the rains. This remedy was proposed, and its entire success demonstrated, by Professor A. J. Cook, of the Michigan Agricultural College. A tablespoonful of poison to a gallon of water is sufficient."* This represented very nearly the sum of knowledge respecting the spraying of orchards at that time. Just ten years later, the writer had a part in putting before the public a manual on spraying,† which made a closely printed book of some four hundred pages. These contrasts will serve to show how rapid has been the evolution of the spraying of plants to combat insects and diseases. This sudden development of the spraying of orchards has tended

*"Field Notes on Apple Culture," 88.

† Lodeman, "The Spraying of Plants." This work should be consulted when full information is desired upon the history and practice of spraying.

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to magnify its importance out of all proportion to other accustomed operations of fruit-growing. The practice has been hailed as a positive means of making orchards fruitful. As a matter of fact, however, it makes orchards fruitful only when the cause of unfruitfulness is incursions of insects and fungi. It will not correct the faults of poor tillage, nor of insufficient plant-food, nor of unprofitable varieties, nor of neglect in pruning. In other words, it is only one of the various elements which enter into successful fruit-growing. Wholly aside from its direct and immediate importance, spraying has had an emphatic secondary influence in waking up the horticulturist. Any movement which sets a man to thinking very strongly along one line is likely to awaken his interest in cognate subjects. So it happens that spraying has been one of the means of rapidly diffusing a better knowledge of horticultural operations. Some of the directions in which this secondary influence of spraying is bound to enlarge the horticultural horizon may be stated as follows:

1. The necessity of spraying calls the attention of the grower to the reasons for the recent incursions of pests. Spraying was unknown in his boyhood days. Why is it so imperative now? This opens a volume of suggestion, and will lead the questioner to consider the fact that insects and fungi are constantly changing their habits from one plant to another, as the native plants are destroyed and as the area of cultivated ones is increased, and

that the continuing commerce with all parts of the world constantly exposes us to new dangers. Pests which have latterly broken out with fury have been breeding in unobserved numbers in the neglected plantations for many years. The ideals of the fruitgrower are also higher now than they were a few years ago. Competition has increased, and the smallest blemish on a fruit is enough to throw it out of a first-class article, whilst a few years since it might have passed without comment.

2. The necessity of spraying is bound to force new ideals upon the grower. Those persons who grow in a large way for the general and more or less staple markets will find themselves casting about for those varieties which are least susceptible to disease and insect injury and which, therefore, need the smallest amount of attention in the way of

sprays.

3. On the other hand, the protection which spraying affords will tend to bring in many of those good old varieties which, like the Virgalieu pear, have almost disappeared from cultivation because of disease. Those persons who are growing special kinds of fruit for particular or personal markets will select the varieties of ideal qualities almost independently of the liability to insect or fungous attacks, because they are now assured that these attacks can be overcome. On the one hand, therefore, spraying will force the selection of varieties which do not demand this extra care and treatment; and, upon the other hand, it will afford the grower of fruits for dessert

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and home use the protection which he has heretofore not enjoyed.

4. Spraying is bound to force a closer study of the companionships and inter-relations of crops, fungi and insects. It will teach the farmer to observe that certain pests follow the round of certain crops, and that when he breaks such a rotation he also lessens the liability of attack. It will also force him to the use of shorter rotations, for it is a very nimble insect or fungus which can keep pace with a lively and resourceful farmer. He will come to learn that the best treatment of the anthracnose on raspberries may be a short rotation rather than spraying. In fact, the best treatment may be a combination of both; but he will find that if he reduces the number of crops to two or at most to three, and then has plantations coming on in other land, he will suffer comparatively little. The same suggestion is extremely applicable to the cultivation of strawberries.

5. Spraying will take its place along with tillage, fertilizing, pruning, and the other cardinal operations of the fruit plantation.

6. Spraying is bound to force better care, in order that the crop may repay the extra cost of the treatment. The advent of the potato bug has no doubt exercised a very pronounced influence in improving the cultivation of the potato, and it is probably not too much to hope that the apple-scab is bound to revolutionize apple - growing in the northeastern states.

7. The necessity of spraying must create a greater watchfulness on the part of the fruit-grower for new pests, for these pests are all the time appearing from foreign countries, from adjacent states or geographical regions, or from the wild.

8. Inasmuch as every new subject of inquiry. awakens new thoughts and expands one's sympathies, so it becomes a means of enlarging and educating the man. A concentrated invasion of the army-worm is one of the very best means of waking up any farming community and of setting every man, woman and child to asking questions of every passer-by, every agricultural editor and teacher, and experiment station. The good effects of such an invasion are likely to last for a number of years. It is surprising, as one thinks of it, how easily people are scared by a bug! A strange insect, which perhaps does not weigh a grain, will set a whole community of ablebodied men agog, and may cause as much downright fear and discussion as a political revolution.

A

There are three general types of difficulties which are germane to the discussion in this chapter. classification of these troubles might be made as follows:

1. Attacks by insects.

(a) The injuries of those insects which eat or chew the parts of the plant, and which, therefore, are killed by the application of poisons like Paris green. Such insects are the whole tribe of caterpillars, worms and beetles.