334 INSECTS AND DISEASES. 



washing recommended, a strong steam must 

 be raised morning and evening by pouring 

 water upon the heated flues. 



Trees that have the composition, as di- 

 rected for each kind, applied to them in 

 autumn, will very seldom be infested by the 

 red spider, as the composition destroys all 

 the eggs which may be upon that part of 

 the tree to which it is applied. Care must 

 also be taken to clean the walls. (See the 

 Chapter on nailing fruit trees.) 



On the Aphis, or Green Fly. 



The green fly or plant louse, attacks most 

 kinds of fruit trees, but particularly Peaches 

 and Nectarines. Their attacks are princi- 

 pally directed to the ends of the young shoots, 

 and their ravages are rendered the more de- 

 structive, by reason of the very critical time 

 at which they attack the trees, which is fre- 

 quently before the young leaves have ex- 

 panded themselves. 



The reason of their being so prevalent at 

 so early a season is, that whenever any of 

 their eggs have been deposited in any part 

 of the tree or wall (as they will frequently 

 deposit them at the end of autumn behind 

 the buds, or at the divisions of the shoots) 

 they are hatched by the influence of the sun 

 in spring, and the first bro<5d of those insects 



