INSECTS INJURIOUS TO THE APPLE AND PEAR 631 



at this time it is well to add the arsenical, which but slightly 

 increases the cost. Where there is a full second generation, as 

 in most of the Middle and Pacific States, a third application as 



FIG. 488. Work of the first generation of codling moth larvae. 



the second generation of larva) are hatching, will be found advis- 

 able about nine or ten weeks after the petals fall, and a fourth 

 two or three weeks later may be necessary. With thorough spray- 



FIG. 489. Work of the second generation of codling moth larvae. 



ing not over 1 or 2 per cent of the picked fruit should be wormy, 

 as most of the wormy fruit will drop early in the season. 



In mountainous districts, or where it is difficult to secure water, 

 dusting the trees with Paris green blown by a dusting machine 

 has been quite extensively practiced. Although this treatment 



