The Biological Characteristics Of Encarsia Japonica Viggiani

The biological characteristics of Encarsia japonica Viggiani was studied both at laboratory and in field. The research results are as follows:E. japonica was complete metamorphosis with development process of egg, larva, pupa and adult.The fertilized egg developed into the female of E. japonica, while unfertilized egg developed into the male.Under laboratory condition, the eclosion peak of E. japonica appeared from 6:00 am to 11:00 am. The adults had distinct phototaxis.The stronger the light was, the stronger the adults acted. While the light is weak, the activity also decreased. Under the temperatures of 15~35℃at laboratory, the developmental duration of stages for E. japonica shortened with the rise of temperature, while the development rate increased with the rise of temperature.The correlations between the developmental rate (y) and the developmental temperature (x) of every stage were : egg : y=0.1687x+0.0224 ; larva :y=0.0453x+0.0134;prepupa:y=0.3361x+0.1111;pupa:y=0.0542x+0.0359.The developmental zero and effective cumulative temperature of whole generation for E. japonica were determined as 9.62℃and 239.08 degree-day, respectively.After parastized by E. japonica, Bemisia tabaci only developed to the forth instar nymph. Meanwhile, no matter E. japonica parasitized in the which stage of B. tabaci, all of parasitoids developed to pupa until B. tabaci developed into the forth instar. E. japonica developed with the longest time (14.9±0.75d) from egg to adult when it parasitized in the first instar host, and had the highest parasitic rate (44.9±8.19%) when it parasitized in the third instar host.Four species of aphelinid parasitoids of B. tabaci were collected and identified in Fuzhou of China, including 3 species of Encarsia and 2 species of Eretmocerus.Two parasitic peak of parasitoids on B. tabaci were respectively at mid-July and mid-October.