Branch-mortality
Guides
Oncideres cingulata
twig girdler, Eastern Twig Girdler
Oncideres cingulata, commonly known as the twig girdler, is a cerambycid beetle notable for its distinctive reproductive behavior where adult females girdle twigs of host trees to create larval habitat. The beetle is brownish-gray, 13–16 mm in length, with antennae 13–25 mm long. Adults are active in late summer and fall, and females cut through bark and wood of small branches (6–12.7 mm diameter) before laying eggs in the severed portion. Larvae develop within the fallen girdled twigs, feeding on woody tissue, and complete a single yearly generation. The species is economically significant as a pest of pecan plantations and other hardwood trees.
Phloeosinus punctatus
western cedar bark beetle
Phloeosinus punctatus is a bark beetle in the family Curculionidae, subfamily Scolytinae, known as the western cedar bark beetle. The species colonizes giant sequoia (Sequoiadendron giganteum) and California incense-cedar (Calocedrus decurrens) in the Sierra Nevada mountains of California. Females initiate gallery construction and mate monogamously. The beetle undergoes four larval instars, typically producing one generation per year under natural conditions. It has been observed to contribute to branch mortality in giant sequoia, particularly when trees are under environmental stress.