CHERRY INSECTS 1147 



attached to the bark of the smaller branches, generally near the 

 buds. They hatch just us the buds arc opening, and the young 

 lice cluster on the opening buds. These lice are all females and 

 reproduce without being fertilized. They multiply with wonder- 

 ful rapidity, so that within a few weeks the undersides of the 

 leaves and the tip of the branches are thickly covered with them. 

 The leaves become curled, the branches stunted, the fruit remains 

 small and may fall prematurely (Fig. 372.). 



Control 



The cherry plant-louse can be controlled by very thorough 

 spraying with " Black Leaf 40 " tobacco extract, 1 pint to 100 

 gallons of water in which 5 pounds of soap has been dissolved. At 

 least 10 gallons of this mixture should be applied to a tree of 

 moderate size. The application should be made while the lice are 

 clustered on the opening buds. They are then relatively few in 

 number and are exposed so that they -can easily be hit with the 

 spray. After the lice have curled the leaves it is very difficult 

 to reach them. To be successful the work should be done at the 

 right time and with thoroughness, 



THE PEAR SLUG 



The pear slug (Eriocampoides limacina) is also a serious enemy 

 of the cherry. The injury is most severe on trees recently 

 planted ; the slugs may destroy the foliage of such trees before they 

 become fully established, with the result that a large proportion 

 are killed. 



The pear slug passes the winter in the larval stage in earthen 

 cocoons two or three inches below the surface of the ground. The 

 transformation to the. adult takes place in the spring, and the 

 glossy black, four-winged flies appear on the trees about the middle 

 of May. The female is provided with a sharp saw-edged ovipositor 

 by means of which she inserts her eggs in a blisterlike cavity be- 

 tween the two layers of the leaf. The egg hatches in about two 

 weeks, and the larva escapes through a cut on the upper surface of 

 the leaf. The larvae soon become covered with a sticky slime, 

 which is retained until they are full-grown and which gives them 

 the appearance of small snails. In form they somewhat resemble 



