THE PEARS OF NEW YORK 1 19 



inconspicuous as they rest during the day on the bark of the pear-tree 

 which they closely resemble; they fly only at dusk. The moth lays its 

 eggs on leaves or the fruit itself and the young larvae immediately begin 

 work on the nearest pear. Control consists in spraying with arsenate of 

 lead. Two and sometimes three sprayings are necessary. The most 

 important spraying is made just after the blossoms fall, while the calyx- 

 cup is still open, so that the poison will lodge in the blossom-end of the 

 upturned pear. Codling moth was once a most serious pest of the pear, 

 but is now easily kept under control by seasonal applications of arsenate 

 of lead. 



The pear-slug (Caliroa cerasi Linnaeus), a generation ago, before 

 spraying was common, did much damage to the pear in New York, but is 

 now a negligible pest except in the orchards of the indifferent or slothful 

 since it is easily controlled by spraying. The slugs are small, dark green 

 shiny creatures which eat the surface of the leaves of pear, cherry, and 

 plum. They devour the upper surface of the leaf leaving the veins and 

 the tissues of the lower surface, which turn brown so that the infested 

 tree has the aspect of having been scorched by fire. The slugs molt and 

 finally lose their shiny coat and dirty green color, the full-grown larvae 

 becoming clear yellow. The adult is one of the numerous saw-flys. Eggs 

 are laid within the tissues of the leaves. There are two or three generations 

 in a season. The slugs are most common in the hottest part of the summer 

 or late in the summer. This pest is easily kept in check by applications 

 of arsenate of lead. 



The foliage of the pear, in common with that of the apple, is often 

 seriously injured by a mite (Eriophyes pyri Pgst.) which burrows into 

 the tissues of the leaves. The mites attack the young leaves causing 

 reddish blisters which turn black. The blisters are thickened spots which 

 are found to have a corky texture. The young fruits are sometimes 

 attacked, in which case they are badly malformed. The mites are of 

 microscopic size and can be seen only by the aid of a magnifying glass. 

 They hibernate under the scales of the leaf -buds, and are thus ready to 

 attack the young leaves as soon as they unfold, which they do by eating 

 their way in from the under side and then by their work cause the char- 

 acteristic swellings. As they mature, the mites come out and move to new 

 places and start more colonies. In the autumn, they find their way to the 

 maturing buds and go into winter quarters. An application of lime-sulphur 

 solution at winter strength usually disposes of the mites; that put on for 



