Abstract: This paper deals with the natural dynamics of Eriococcus lagerostroemiae Kuwana popu lation. This insect pest spread into Guiyang, Guizhou Province, in the late 1980s and occurred3-4 generations during a year. A mixture of the third and fourth generations overwintered. Itcould survive the winter in egg, nymph and pupa. The threshold temperature of development (T₀) was estimated to be -0.3℃ for egg, 17.5℃ for male nymph, 14.2℃ for pupa, 18.8℃ for female nymph and 10.2 C for female adult, with effective temperature summations (K) of 540.8, 88.4, 73.0, 98.0 and 79.1 day-degree, respectively. There were two peaks in population fluctuation each year, which appeared at midde June to early July and early August to early September. The population density gradually decreased from November to early April as the host plant, Largerstroemia indica L., entered dormant stage and the temperature got lower. The fecundity of the female adult depended on the growth state of the host, the better the tree grew, the more the egg was laid. The lady beetle, Chilocorus kuwanae Silverstri, was the most effective natural enemy controlling the pest. A better chemical control method is to smear pesticide on the tree truck, branches and twigs and watering with systemic insecticide as a supplementary means.

Key words: Eriococcus lagerostroemiae, biological characteristics, threshold temperature, effec-tive temperature summation, population dynamics