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Cultivation and Susceptibility to Insect Attack

1908; Oxford University Press; Volume: 1; Issue: 1 Linguagem: Inglês

10.1093/jee/1.1.15

1938-291X

John B. Smith,

Forest Insect Ecology and Management

It is a common complaint in New Jersey by fruit growers that care best for their orchards, that some of their neighbors that never spray suffer less from the pernicious scale than they; and there is a basis of tact for the complaint. In almost every section of the state there are old orchards, chiefly apple, that bear annual crops of good or fair fruit, practically free from scale, though no spraying work is ever done in the orchards and the trees have been infested for years. Investigation brought out a few facts that seem to be suggestive. First, as a rule, vigorous, sappy growth is much more generally infested and injured than slow, hardy growth. Second, trees growing in well cultivated orchards, highly fertilized, are much more likely to suffer from scale attack than others. Third, trees that grow slowly, or in sod, without much care, are much the more resistant to scale attack. Fourth, trees that become infested while young and growing vigorously, suffer much more than trees that do not become infested until they have reached bearing age. Fifth, trees that have been infested for some years, have been more or less persistently treated so as to keep down the insects, and have then been abandoned, not infrequently clean themselves and become and remain practically free from scale afterward. Some suggestions derived from these facts are, that possibly trees are being stimulated to rapid growth at the expense of hardiness, and that the nitrogenous fertilizers used to produce quick and large trees actually lessen resistant power to insect attack. It would seem in place to inquire whether there should not be a modification of our practice that would induce a hardier growth and one more resistant to scale attack. Instead of adopting a practice calculated to secure size, try to secure one that would give greater hardiness even at the expense of mere growth. That there is a variation in susceptibility among varieties is universally known; it should not be impossible by selection and proper treatment to secure both quality and resistance. It is unscientific to devote ourselves merely to securing and testing spray mixtures, however necessary these may be for immediate results, if there is a possibility of securing exemption by increasing resistance or by adoption of fertilizing methods more in accord with the real needs of the plants.