The species of the curculio that penetrate the fruit of the apple, pear, plum, apricot, cherry, and peach are not identical, but their methods of working and treatment are nearly the same. The apple and pear curculio does not often do much damage at the North, but in some of the Central States it is very destructive in the way of knotting and distorting the fruit. The plum curculio also frequently feeds on the apple and its work is about identical with that of the apple curculio.
The plum curculio or "Little Turk" is the most serious pest of the plum orchard, and it also works on the cherry. The plum, prune, apricot, and peach usually drop the fruit that is perforated by the grub when the pit is reached. But the cherry does not drop, but comes to the front in the hands of the user under the name of "wormy cherries."
A common habit of all the curculios is, when alarmed, to draw up as if dead and drop to the ground. Advantage is taken of this habit in the way of jarring the tree, causing the dropping of the insects on sheets spread beneath during the first stages of fruit development. In the larger-fruit sections an inverted umbrella-like frame covered with cotton cloth, divided in the centre so as to pass the stem, is rolled on low wheels under the trees for the reception of the curculios. The morning and evening are found to be the most favorable periods for this work. In some of the largest commercial stone-fruit orchards of New York, Ohio, and Georgia this plan keeps the curculio in check with less trouble and expense, it is claimed, than can be done by spraying.
But spraying is relied on by other growers of the cherry, plum, and peach. The trees are sprayed, just as the buds begin to expand, with arsenite of lime solution (156. Spraying for Codling-moth). This reaches some of the adult insects under bark scales, and many are on hand to feed on the first opening leaf and fruit buds. The second spraying with the same mixture should be given soon after the blossoms have fallen. If rains follow a third spraying may be required.
In spraying with the arsenite of lime for codling-moth and curculio we are also waging a successful warfare on the canker-worm, tent-caterpillar, bud-moth, and about all leaf- or bud-eating insects.