Page:Popular Science Monthly Volume 42.djvu/660

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THE POPULAR SCIENCE MONTHLY.

hay or loose cloth, to entice the larvæ to spin their cocoons in them, and the feeding of fallen fruit to stock. A serious objection to these methods lay in the fact that the worms were only destroyed after they had done their injury. But now, thanks to the spraying machine, the fruit-grower can place in the calyx ends of the young apples a few particles of poison, which as a rule will kill the newly hatched worms before they enter the fruit. For this purpose three or four ounces of London purple or Paris green are thoroughly mixed with a barrel of water. The apple trees are sprayed with this mixture just after the blossom petals have fallen off. The poison particles are thus distributed over the tree in a fine mist, and when the water in which they are suspended (not dissolved) evaporates, they are left high and dry upon the leaves and fruit, there to remain a menace to insect enemies for several weeks. In the course of time the combined action of rain

 
PSM V42 D660 Plum curculio and the damage caused.jpg
Fig. 2.—Plum Curculio: a, larva; b, pupa; c, beetle—magnified; d, plum showing crescent mark. (After Riley.) Fig. 3.—Apple injured by Curculio.
 

and dew, wind and sunshine dissipate their poisonous properties. By thus destroying the first brood of worms one is saved the trouble of fighting the second brood.

For many years it has been very difficult to produce plums and other stone fruits on account of the injuries of the plum curculio. The adult of this species is a small, hard-shelled beetle (Fig. 2, c), which appears in the orchard early in spring, and feeds upon the foliage and flowers until the fruit is well formed. It then attacks the young plums, gnawing at them to satisfy its hunger, and cutting crescent-shaped holes (d) in the skin for purposes of oviposition. The eggs hatch into minute grubs that feed upon the pulp for a few weeks, ruining the plums and causing them to fall to the ground. The grubs (a) then leave the fallen fruit, enter the soil a short distance, change to pupæ, and later again change to adult beetles. There is but one brood each season, the insects wintering over mostly as beetles.

Besides stone fruits this insect attacks apples and pears, caus-