Walnut Twig Beetle

Pityophthorus juglandis can easily be distinguished from other members of its genus. Curtis Utley, a researcher at Colorado State University, elaborates on these differences stating, "Among these differences there are the 4 to 6 concentric rows of asperities on the prothorax, usually broken and overlapping at the median line. The declivity at the end of the wing covers is steep, very shallowly bisulcate, and at the apex it is generally flattened with small granules." The walnut twig beetles' small size is common for its genus. Adult beetles average between 1.5 and 1.9 millimeters in length. Although little is known about the life-cycle of the walnut twig beetle, during experimentation with the beetle in a controlled environment, the lifespan of one generation of walnut twig beetles was seven weeks after logs of black walnut, Juglans nigra, were harvested from the wild in May, marking what scientists think is the beginning of the feeding season of the walnut twig beetle. Gatherings of the beetle in sections of the walnut tree are known as galleries. The outward appearance of the walnut above these galleries seemed normal except for small beetle entrance holes. …