SOME INSECTS INJURIOUS TO ORCHARD FRUITS 541 



there are four or five generations a year, in the South there are 

 probably more generations, while at the northern limit of the 

 species there are two or possibly three generations, as breeding 

 continues until after killing frosts. As with other small insects, it 



FIG. 392. Peach leaf bearing San Jos6 scales along veins. 



is the remarkable power of reproduction to which the destructive- 

 ness of the pest is due. Thus it has been estimated that at Wash- 

 ington, D. C., the progeny of a single female would number 

 3,216,080,400 by fall, if all were to survive. It is not surprising, 



FIG. 393. Adult female San Jose scale, with scale removed to expose the 

 insect . (After Al wood . ) 



therefore, that a tree with but a few scales on it in spring will be 

 covered by them and the fruit unfit for market in the fall, and that 

 with these millions of little beaks pumping out the sap and poison- 

 ing the tissues a tree soon succumbs. 



