Wheat plant-lice form collectively the third insect pest destructive to wheat, of which it is reported that "the annual loss occasioned by wheat plant-lice probably does not fall short of two or three per cent of the crop."
Hay And Forage Crops. —These are attacked by locusts, grasshoppers, army worms, cut-worms, web worms, small grass worms and leaf hoppers. Some of these pests are so small and work so insidiously that even the farmer is prone to overlook their existence. "A ten per cent shrinkage from these and other pests in grasses and forage plants is a minimum estimate."
Cotton. —The great enemies of the cotton-planter are the cotton boll weevil, the bollworm and the leaf worm; but other insects inflict serious damage. In 1904 the loss occasioned by the boll weevil, chiefly in Texas, was conservatively estimated by an expert, Mr. W.D. Hunter, at $20,000,000. The boll worm of the southwestern cotton states has sometimes caused an annual loss of $12,000,000, or four per cent of the crops in the states affected. Before the use of arsenical poisons, the leaf worm caused an annual loss of from twenty to thirty million dollars; but of late years that total has been greatly reduced.
Fruits. —The insects that reduce our annual fruit crop attack every portion of the tree and its product. The woolly aphis attacks the roots of the fruit tree, the trunk and limbs are preyed upon by millions of scale insects and borers, the leaves are devastated by the all-devouring leaf worms, canker worms and tent caterpillars, while the fruit itself is attacked by the codling moth, curculio and apple maggot. To destroy fruit is to take money out of the farmer's pocket, and to attack and injure the tree is like undermining his house itself. By an annual expenditure of about $8,250,000 in cash for spraying apple trees, the destructiveness of the codling moth and curculio have been greatly reduced, but that money is itself a cash loss. Add to this the $12,000,000 of actual shrinkage in the apple crop, and the total annual loss to our apple-growers due to the codling moth and curculio is about $20,000,000. In the high price of apples, a part of this loss falls upon the consumer.
In 1889 Professor Forbes calculated that the annual loss to the fruit-growers of Illinois from insect ravages was $2,375,000. In 1892, insects caused to Nebraska apple-growers a loss computed at $2,000,000 and, in 1897, New York farmers lost $2,500,000 from that cause. "In many sections of the Pacific Northwest the loss was from fifty to seventy-five per cent." (Yearbook, page 470.)
Forests. —"The annual losses occasioned by insect pests to forests and forest products (in the United States) have been estimated by Dr. A.D. Hopkins, special agent in charge of forest insect investigations, at not less than $100,000,000. … It covers both the loss from insect damages to standing timber, and to the crude and manufactured forest products. The annual loss to growing timber is conservatively placed at $70,000,000."
THE GYPSY MOTH, (Portheria dispar)