花角蚜小蜂对松突圆蚧的控制效能及其稳定作用的评估

从日本冲绳引入的松突圆蚧花角蚜小蜂Coccobius azumati Tachikawa是1989年在惠东 县首批释放定居成功的。经五年系统研究表明，花角蚜小蜂释放一年后，在中心区50m以内最高寄生率达55.8%～64.2%，雌蚧密度由每针束3.14头下降为0.64头；二年后控制松突圆蚧的有效半径增至300m左右，寄生率稳定在20.8%～32.9%，每针束雌蚧密度保持在0.6头左右，二者处于低密度的平衡状态。未放蜂对照区的雌蚧密度则由每针束3.40头上升到4.22头，高出放蜂区5～10倍。此外本报告还对花角蚜小蜂的扩散速度、种间竞争能力和数量稳定水平作了探讨和分析，得出瘦柄花翅蚜小蜂Marietta cdrnesi(Howard)在花角蚜小蜂释放区内的重寄生率仅为3.1%～5.3%，对花角蚜小蜂的控制效能没有影响的结论。

EVALUATION ON THE EFFECTIVE AND STABLE CONTROL OF HEMIBERLESIA PITYSOPHILA TAKAGI WITH COCCOBIUS AZUMAI TACHIKAWA

Coccobius azumai Tachikawa which was introduced from Okinawa, Japan, was first released and successfully established in Huidong County, Guangdong Province in 1989.Since then systematic observation and investigatlon were made. The result showed that a year later the parasitism rate of C. azumai on Hemiberlesia pitysophila reached as high as 55. 8 % ~ 64. 2 % within 50 m from the released site and the density of female H. pitysophila was reduced from 3. 41 to 0. 64 per needle. Two years later the effective control radius had increased to about 300 m. The parasitism rate ranged from 20. 8 % to 32. 9 %. The density of female H. pitysophila became as low as 0. 6 per needle. Both C. azumai and H. pitysophila were in a balanced state of low density, whereas in the areas where no C. azumai was released, the density of female H. pitysophila had increased from 3. 4 t0 4. 22 per needle, 6~ 10 times higher than that in the released area. Judging from the spreading speed,competitive ability and the number-stabilizing level of C. azumai, it is concluded that Marietta carnesi (Howard) had only a hyperparasitism rate of 3. 1 % ~ 5. 3 % so that it had no influence on the control efficiency of C. azumai.