Treatment. Destroy orchard trash which may serve as a winter home. Scrape all loose bark from the tree. Spray the tree with arsenate of lead as soon as the flowers fall. A former method of fighting this pest was as follows: bands of burlap four inches wide tied around the tree furnished a hiding-place for larvæ that came from windfalls or crawled from wormy apples on the tree. The larvæ caught under the bands were killed every five or six days. We know now, however, that a thorough spraying just after the blossoms fall kills the worms and renders the bands unnecessary. Furthermore, spraying prevents wormy apples, while banding does not. Follow the first spraying by a second two weeks later.
It is best to use lime-sulphur mixture or the Bordeaux mixture with arsenate of lead for a spray. Thus one spraying serves against both fungi and insects.
Fig. 154. Plum Curculio
Larva, pupa, adult, and mark on the fruit.
(Enlarged)
Fig. 155. Leaf Galls of
Phylloxera On Clinton
Grape Leaf
The Plum Curculio. The plum curculio, sometimes called the plum weevil, is a little creature about one fifth of an inch long. In spite of its small size the curculio does, if neglected, great damage to our fruit crop. It injures peaches, plums, and cherries by stinging the fruit as soon as it is formed. The word "stinging" when applied to insects—- and this case is no exception—means piercing the object with the egg-layer (ovipositor) and depositing the egg. Some insects occasionally use the ovipositor merely for defense. The curculio has an especially interesting method of laying her egg. First she digs a hole, in which she places the egg and pushes it well down. Then with her snout she makes a crescent-shaped cut in the skin of the plum, around the egg. This mark is shown in Fig. 154. As this peculiar cut is followed by a flow of gum, you will always be able to recognize the work of the curculio. Having finished with one plum, this industrious worker makes her way to other plums until her eggs are all laid. The maggotlike larva soon hatches, burrows through the fruit, and causes it to drop before ripening. The larva then enters the ground to a depth of several inches. There it becomes a pupa, and later, as a mature beetle, emerges and winters in cracks and crevices.
Treatment. Burn orchard trash which may serve as winter quarters. Spraying with arsenate of lead, using two pounds of the mixture to fifty gallons of water, is the only successful treatment for the curculio. For plums and peaches, spray first when the fruit is free from the calyx caps, or dried flower-buds. Repeat the spraying two weeks later. For late peaches spray a third time two weeks after the second spraying. This poisonous spray will kill the beetles while they are feeding or cutting holes in which to lay their eggs.
Fig. 156. The Cankerworm