54 RATIONAL FRUIT CULTURE 



CHAPTER X. 



INJURIOUS INSKCTS. 



THERE are, unfortunately, a large number of different 

 kinds of insects which attack fruit trees. Some injure 

 the foliage, others the buds, others the blossom, and 

 others the branches or the roots, while several do not confine 

 themselves to a single part. Unless prompt measures are 

 taken against them, they may cause the loss of the crop and 

 seriously damage, if not destroy, the trees. 



DIFFERENT CLASSES OF INSECTS. 



One of the most effective measures is spraying. For this 

 purpose the insects under consideration may be divided into 

 two classes — those which eat the tissues, and those which 

 merely suck the sap. Among the former are caterpillars of 

 various species, and among the latter aphides and mussel 

 scale. As all insects breathe through pores in their bodies, 

 they must die if the pores are blocked up hy soapy or oily 

 liquids. This method is the one generally employed against 

 the sap-suckers. It, is, however, useless against hairy cater- 

 pillars, which form the greater part of the tissue-feeding class, 

 for the hairs prevent the liquid from reaching their skins. To 

 kill them we must ])oison their food. Hut when every care 

 is taken, some of the insects are almost sure to escape, and 

 when they hiheriiute or lay their eggs on the trees, they should 

 be (l(^st^oyed in winter. This should he done by means ^f a 

 burning liquid, applied after the leaves fall and hel'ore they 

 begin to grow again. 



