Threshold and effective accumulative temperature for the development of Plagiodera versicolora

The developmental duration,developmental threshold and effective accumulative temperature of Plagiodera versicolora,an important insect pest of Salicaceae plants,were studied in the laboratory.The results show that under four constant temperatures ranging from 15 to 35℃,the durations of various stages of Plagiodera versicolora were shortened with an increase in temperature.Based on the results at constant temperatures,the threshold temperatures of egg,larvae,pupae,pre-oviposition and a generation were estimated to be 11.99,10.33,11.26,11.38 and 10.11℃ respectively.The effective accumulative temperatures were 43.04,132.86,38.74,74.95 and 317.87 d·℃.Based on the investigation of its annual life history,it is concluded that the occurrence of Plagiodera versicolora was 8.36-8.91 generations annually in Nanjing,capital of south eastern China's Jiangsu Province.