May 2004

4.13

Damage

      After JPB penetrates the bark and reaches the junction of bark and wood, they construct their egg gallery by boring diagonally upward across the grain of the wood for 2 or 3 inches, then vertically parallel to the grain for an additional 2 to 4 feet.  Each egg gallery is constructed

by a single pair of beetles.  As construction of the gallery progresses, the female lays her eggs singly in niches along the sides (fig.3,B), and the gallery is then packed solidly with boring dust and frass. 

Life History

     The life cycle of JPB is ordinarily completed in 1 year in the northern part of the range, but in the southern part two generations per year may occur. Frequently, one complete and a partial second generation develop.  The principal period of attack is in June and July, but attacks can also occur through September into early October.  The beetle most often overwinters in the larval stage but will also overwinter in the adult stage.   
     The eggs hatch in 1-3 weeks. The length of the larval period varies

considerably as most of the insects overwinter in the larval stage.  Mature larvae pupate in cells constructed at

Figure 1. Distribution of the Jeffrey pine beetle in North America.