| The population of Phaedon brassicae Baly has rising in southern part of China, especially in area of Jiangsu and Zhejiang in recent years. The outbreak of P. brassicae resulted in cruciferous vegetable yield and economic loss. In this paper, study benefited to know outbreak mechanism and disaster regulation of P. brassicae. The major contents included effects of temperature and photoperiod on experimental population, cold-hardiness and starvation endurance of this pest. The change of activity of SOD under different temperature of the pest was also studied in system. The main results were as following.1. Effects of temperature on experimental population of P. brassicae were studied in this paper. Development rates of P. brassicae were observed at six constant temperatures ranging from 16 to 31℃. The relationship between temperatures and development rates of P. brassicae were fitted by Wang-Lan-Ding model. The development threshold and thermal requirement for its development at different stages were estimated by the direct optimum method. The development threshold of egg, larva, pupa, preoviposition and generation were 8.19, 10.09, 7.08, 14.20, 11.67℃respectively. Thermal requirements of egg, larva, pupa, preoviposition and generation were 66.69, 147.50, 62.50, 216.28, 492.90 day degree respectively. Experiment of adverse temperature on P. brassicae was carried out. The results showed that adult could survive 18d under -8℃, 13d under -12℃. The survive rate of adult treated under 40℃6d later still was 7.33 percent and 48 percent under 37℃. In conclusion, adult could endure cold-hardiness and hot-hardiness.2. Cold-hardiness of P. brassicae was tested. The main results were as following. Among adult, egg, larva and pupa, the super-cooling point and the freezing point of egg were -21.57±0.53℃and -20.56±0.51℃respectively, which were lower than other stages. The super-cooling point and the freezing point of the 3rd instar larva were -12.43±0.39℃and -7.19±0.21℃respectively, which were higher than other stages. The sequence of super-cooling point from low to high is egg < pupa < female -1 under 28℃, while 142.06±3.63U·mg-1 under 36℃. Adults and pupae could adapt themselves to the temperature of 0℃more easily. It is possible that adults and pupae could live through the winter more safely than other stages.6. Several insecticide for P. brassicae were tested in laboratory and field to choose the better insecticide. The results showed that 5% fipronil SC and 1% emamectin benzoate EC have a good effect on the control of P. brassicae among 6 insecticides. Their toxicant dilution (2000 times) can control above 85 percent of lavae and adults in laboratory 3 days later. 100 percent of lavae and 55 percent of adults were controlled after three day by spraying the 1500 times dilution in field. Both 5% fipronil SC and 1% emamectin benzoate EC can be used as the effective insecticide to spread at local place and to use by turns.
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