Abstract: Phragmataeeia eastaneae is the dominant species of stem borers of Dongting Lake region. Observations on its biology and control experiments were carried out in the Yuaniiang County. The results showed that it has one generation per year, and overwinters as larva in the soil. It has eight larval instars and the data of measurements of head widths showed that the growth increment between adiacent instars was approximately 1.3. Observation was made on the durations of egg and pupa, and the weight of pupa can be used to predict fecundity. The average number of eggs laid per female was 358. The rates of respiration and supercooling points of the overwintering larvae were determined. Some measures of its control are suggested.

Key words: reed——Phragmataecia castaneae——biology