72 



Lessons in Fruit Growing. 



able part of its leaves. The insect is so minute as to be 

 scarcely visible without a magnifying glass. Flies and ants 

 gather about in large numbers to sip the sweet sap and are 

 often mistaken for the cause of the mischief. 



Preventive measures. Spraying the trees with kerosene 

 emulsion on the first appearance of the trouble generally 

 prevents serious damage. 



81. The pear-tree Slu§: {Selcmdriacerasi) is a soft, slimy, 

 blackish or olive-brown, snail-like insect (Fig. 22) that often 

 attacks the foliage of the pear in summer, 

 and sometimes almost defoliates the trees 

 before it is discovered. The insect has two 

 broods, the first of which commonly ap- 

 pears about the middle of June. 



Preventive measures. As this insect feeds 

 upon the upper surface of the leaves, it is 

 readily destroyed by spraying with kero- 

 sene emulsion, or with water containing 

 fresh hellebore powder at the rate of a 

 heaping teaspoonful to three gallons. Trees 

 not bearing fruit may be sprayed with 

 water containing Paris green or London 

 purple. Air-slacked lime dusted over the Fia.22.' 



foliage is also said to be effectual. 



The fire blight has been considered in treating the apple 

 (62). The only special precaution to be observed in the 

 case of the pear is to prevent the growth of fruit spurs on 

 the larger branches of the tree. The disease more often 

 affects the fruit spurs of the pear than of other fruits, 

 hence preventing the growth of these on the main branches 

 tends to restrict the disease to the smaller branches, which 

 may be cut off with less damage to the tree. 



• Pear-tree slug. (After Saunders.) 



