230 Peach-Gromng 



Life history and habits of shot-hole borer. 



The adult appears in the early part of the season from 

 April to June, depending on the latitude, and at once pro- 

 ceeds to gnaw a round hole through the bark where, be- 

 tween the bark and the sapwood, its brood chamber, ex- 

 tending with the grain of the wood, is constructed. 



A single female produces, on an average, from seventy- 

 jfive to ninety eggs. They hatch in three or four days, and 

 the larvae begin to burrow in the sapwood, working at first 

 in a direction at right angles to the brood chamber. They 

 feed from thirty to thirty-six days and then pupate within 

 their burrows. In the North there are two generations 

 each season; in the South, three or four. The winter is 

 passed in the larval form in the tree. 



Methods of control. 



Limbs or other parts of trees, once infested, cannot be 

 freed from the insects by any treatment. By cutting off 

 such limbs and burning them, further infestation may be 

 avoided. As preventive measures, good orchard sanita- 

 tion is important. The trees should be maintained in a 

 vigorous, healthy condition. Trees that are made weak 

 by any means whatsoever are a menace in that they may 

 attract these insects and become a breeding place for them. 



All prunings and dead or dying wood from other sources 

 should be removed and burned, as they may harbor the 

 beetles or larvae. 



Sometimes trees otherwise healthy that become moderately 

 attacked can be saved by heading back the limbs rather 

 heavily, then stimulating vigorous growth by tillage and 

 fertilizers. This course prevents such trees from becoming 

 weakened by the initial attacks. 



