214 



APPLIED ENTOMOLOGY 



In some cases summer treatment may be desirable where the scale 

 is increasing rapidly, to preserve the tree until winter gives an oppor- 

 tunity for the regular application. In such cases a greater dilution of the 

 lime-sulfur becomes necessary, and with' stone-fruit trees the self-boiled 

 material should be used. 



Fumigation with Hydrocyanic acid gas is the most effective treatment 

 for the San Jose Scale, but the cost of the tents large enough to cover all 

 but the smallest trees is so great that this method is made use of only for 

 fumigating nursery stock after it has been dug, in houses built for that 

 purpose. 



Fig. 207.— Rose Scales (Aulacaspis rosm Bouche) : a, female scales; h, male scales. 

 Considerably enlarged. (From Houser, Ohio Agr. Exp. Sta. Bull. 332.) 



The Rose Scale (Aulacaspis rosce Bouche). — Generally distributed in the 

 United States on raspberry, blackberry, dewberry, rose, pear and some other 

 plants. Female scales (Fig. 207) white with more or less yellow at margin; 

 nearly circular, about one-tenth of an inch in diameter. Male scales white, nar- 

 row, very small. Plants thickly infested appear as though sprayed with white- 



