Abstract: The sand sagebrush carpenterworm, Holcocerus artemisiae Chou et Hua, is a severe pest of Artemisia ordosica and A. sphaerocephala, with the larval stages boring into the roots of the host plants. Morphological and biological characteristics of H. artemisiae in Ningxia were studied through field survey and laboratory breeding and observation. The results showed that a generation takes two years in fields of Ningxia. Larvae of all instars were found to overwinter in the host plant roots. Mature larvae begin to pupate in mid May in the soil around the base of plant stems, with the average pupal stage lasting 19.5±3.5 d. Moths emerge from the beginning of June to the end of August, with three peaks of eclosion observed in the early June, early July and early August, respectively. Adult emergence occurs mainly in the afternoon (between 14:00-17:00), and takes 30-45 min. Copulation peaks in the late evening (around 20:00-21:00). The longevity of adults is 2-3 d for males and 1-3 d for females, with a sex ratio of 1∶2.16 (female ∶male) in Ningxia fields. Female moths start laying eggs near mid June, and the eggs hatch in late June. Larvae consume a single root alone in irregular tunnels before transferring to another. They were found to cause 11%-44% damage (average 24%) on A. ordosica from May to September, with a population density of 0.13 individuals per root. There was a significant difference in the selectivity of H. artemisiae larvae to tree age (1-4 years) and ground diameter (16-34 mm). The systematic research of biological characteristics of H. artemisiae provides scientific evidence for its control.

Key words: Holcocerus artemisiae, morphological characteristics, biology, life habits, life history, natural enemies