Insect and Disease Control 223 



to be from about July 15 to August 15. In the middle 

 latitudes emergence extends from about June 15 to Sep- 

 tember 15, while in southern latitudes it continues until 

 about October 1. The laying of eggs begins as soon as the 

 moths emerge. 



The eggs are too small to be seen readily on the bark of 

 the trunk, where they are laid rather promiscuously as well 

 as on adjacent weeds and trash and even on the ground. 

 They hatch in nine or ten days, and the young larvae soon 

 begin to burrow through the bark at the surface of the ground 

 into the sapwood, where they continue until full grown, 

 working just beneath the bark and sometimes extending 

 down the larger roots six or eight inches below the surface 

 of the ground. 



The full-grown larva is about 1 inch in length with a very 

 light yellow body. There is but one generation in a season, 

 but because egg-laying continues for so long a period, larvae 

 varying greatly in size may be found in a tree at the same 

 time. 



The presence of borers in a tree is indicated by a mass 

 of gummy material which habitually exudes from the bur- 

 rows at the surface of the ground. It is often mixed with 

 particles of soil and frass. In rainy weather it becomes 

 gelatinous in texture. 



Method of control of borer. 



Passing mention only need be made of the numerous 

 washes, different methods of wrapping, and the like that 

 have been recommended from time to time. None of these 

 measures, however, is more than partially effective, and 

 many are entirely useless. After an exhaustive investigation 

 of a great number of them, Slingerland of the Cornell Uni- 



