In addition to these insects that attack special plants, all vegetables are preyed on by the grub-worm, the cutworm, the aphis and various tiny hoppers.
The grub-worms which work about the roots of plants are, in the adult state, the June-bugs or cock-chafers which fly about our lights in the spring and early summer, and which themselves do considerable damage by eating leaves of trees and bushes.
Orchards and small fruits suffer heavily from insect pests, both on account of the direct loss and on account of the expensive treatment. There are several hundred insects which ravage fruit trees, attacking the roots, trunk, foliage and fruit.
Among these are the scales, of which there are many species, but of which the most widely known and dreaded is the San Jose scale, so called because San Jose, California, was its starting place in America. It is the only one of the scales which, if not checked, will, in two or three years, completely destroy the tree on which it feeds. It attacks the citrus fruits, orange, lemon, grape-fruit, and the apple, pear, and peach as well as small fruits, particularly currants.
Among the many varieties that do serious damage are the black olive scale, plum scale, hickory scale, locust scale, frosted black scale, red oak scale, the cottony maple scale, greedy scale and oyster shell scale.
The woolly aphis injures the roots of our fruit trees; the trunk and limb borers, the peach tree borer, the apple borer, all stand ready to assail the life of the entire tree. The various leaf worms attack the life of the tree also. The grape-leaf skeletonizer eats every particle of green from the leaves, leaving only the veins. The canker-worms and the destructive tent-caterpillars also cause the death of many fruit trees.
Of insects which attack the fruit, the list is long. The codling-moth of the apple causes a greater money loss than any other enemy of fruits. Various estimates of the loss have been made, and in general it is believed that it causes the loss of one-fourth to one-half of the apple crop of the United States each year.
The plum-curculio attacks nearly all stone fruits. Its natural food plant is probably the native wild plum, and the plum continues to be its favorite food, consequently this fruit suffers most from the attacks of the insect. In years of short crops very little fruit remains on the tree to ripen. But peaches, apricots and cherries also suffer heavily, and apples and pears in a less degree.
The insects which injure the hardwood forest trees are principally the leaf-eaters, such as the gypsy and brown tail moths, which have almost stripped the New England shade trees, and done great damage to the forests; the elm leaf beetles and the numerous borers, both beetles and grubs, which from eggs laid in or just beneath the bark, hatch into larvæ which burrow into the wood, destroying its usefulness for lumber. Among the borers which do most injury in destroying valuable timber are the hickory-bark beetle, the bark-boring grubs which kill oak, chestnut, birch and poplar trees, the locust borer, the chestnut timber-worm and the Columbian timber beetle.
All these represent the loss from insects to the growing product; but when it is stored, there is seemingly no less danger of attack by a different class of insects. These include grain weevils and beetles, flour-moths, the small fruit and vinegar flies, buffalo-moths and dozens of others.