Abstract: Hyposidra talaca Walker is one of the important pests of Acacia mearnsii in Fujian province. This paper reports the results of the studies on the bionomics and control of this pest from 1988 to 1991. It has five generations a year in Huaan of Fujian province. In the field generations are overlapping. Winter is passed as pupae in the soil. The adult moths begin to appear in mid-March next year. The eggs are laid stack on the tender twigs and tender leaves and the average number of eggs laid by per female is 592. The eggs stage lasts 4-9 days. Five instars are observed in the larval development which lasts 23-43 days. The overwintering pupal stage lasts 101-122 days and the others last 7-16 days. The adult butterflies live for 3-9 days. The effective measures to control the larvae are spraying with 40% omethoate, 50% metharmidophos, 20% fenvalerate or 2. 5% deltamethria.