There are beautiful forms in these fragile fungus threads that eat their way into the tissues of the host. There are fascinating phenomena in the growth and reproduction. Even so and for all that, man protects his tree by spraying it with poison, and thereby again does he have dominion.
The spraying for apple-scab is with lime-sulfur to which may be added arsenate of lead. This treatment, properly timed, may suffice also for the codlin-moth. As the fungus may attack the flower-stems and kill them, so is the first application made when the flower-buds open and the stems begin to separate, but before the flowers expand; the operator has a period of one to three days in which to spray. A second spraying is given just after the blossoms fall, as for codlin-moth; if the season is wet, a third application may be made ten to fourteen days later; if the fungus seems to spread, a fourth spraying may be applied in midsummer. These sprayings, variously modified, control not only the codlin-moth and the scab fungus but also scale, blister-mite, plant-lice, leaf-roller, case-bearer, bud-moth, red-bug and others.
In the tropics one sees trees bearing great burdens of orchids and bromeliads and ferns and mosses, and one wonders at the strange and exuberant population. Yet here is my apple-tree supporting epiphytes and parasites and insects, protector and nurse of a goodly company; and birds nest on the branches thereof.
XV
THE APPLE-TREE REGIONS
The northern hemisphere is the home of the apple, particularly Central Europe, Canada, the United States. In certain regions in the southern hemisphere the temperature and humidity are right for the good growing of apples, mostly in elevated areas. In New Zealand and parts of Australia, apple-growing is assuming large proportions. Their export trade to Europe and parts of South America has come to be important and undoubtedly is destined greatly to increase.
In Europe, where land is often limited and high in price, apple-trees may be planted closer than in America, even in field conditions, and more attention is given to pruning, heading-in, and the development of fruit-spurs in the interior of the tree-top. I noticed this practice in New Zealand, also. In these directions, the Europeans have much to teach us in the careful growing of good apples. In Europe, the definite training of the apple-tree begins in the nursery; quantity-production, with standardization, is not there the aim.
In North America the general practice is to let the tree take its course, reaching its full natural stature. The pruning is mostly corrective, to keep the tree in shape and to prevent the top from becoming too thick, rather than in the development of fruiting wood. The consequence is that our trees become very large, specially in New York and New England where they are long-lived. In the western country, as we have learned, the apple-tree tends to be shorter-lived and does not usually attain such great size. In the New York apple country, orchards may be in good bearing at forty to sixty years from planting, and individual trees may be productive much longer than this. The trees come into good bearing in ten to fifteen years. In the irrigated regions of the West, the trees may be expected to bear a good crop two to five years earlier; to what age they may attain, in large plantations, it is yet too early to state.