Qi, Q. 1989 [Study on the bionomics of Physokermes jezoensis Siraiwa and its control.]. Insect Knowledge 26(1): 23-24.

Notes: The biology and control of the coccid Physokermes jezoensis, which mainly infests Picea asperata, were studied in Taiyuan City, Shanxi, China, in 1984-86. The pest had one generation a year, overwintering as a 2nd-instar nymph on the surface of spruce needles. In early April, the female nymphs of the overwintering generation migrated to the base of annotinous and biennial branches, migration peaking in mid-April. Adults emerged in early May. The adult males lived for 1-2 days and died shortly after mating. Females laid an average of 500 eggs each. Egg hatch peaked in late May-early June. Second-instar nymphs began to overwinter in late October. Measures recommended for control of the pest are removal of infested branches and bark, sprays of Bordeaux mixture in winter to kill the nymphs, and sprays of 50% Sumithion [fenitrothion] or 40% dimethoate emulsion in early June to kill the newly hatched nymphs. The main natural enemies found were Chilocorus rubidus and C. kuwanae.