广东白骨壤群落上的广州小斑螟生物学特性及种群数量消长规律研究

Study on Biology and Population of Oligochroa cantonella in Community of Avicennia marina in Guangdong

广州小斑螟是白骨壤群落上的重要害虫。室内饲养1年可完成7代，第1代至第6代虫历时33～42d，越冬代虫历时122d。幼虫危害嫩芽、嫩叶、叶片和果实，严重受害的白骨壤林成片枯死。在白骨壤群落，各地受害嫩芽和受害叶片数量变化规律不相同，广州小斑螟种群数量消长规律与受害嫩芽和受害叶片数量变化规律成正相关，受害嫩芽和受害叶片全年平均数保持为10．8—21．5片叶（个嫩芽）／m2，害虫数量全年平均数保持在4．4～20．4头／30个1m2样方。捕食性蜘蛛是控制广州小斑螟种群的重要天敌，蜘蛛数量全年平均数保持在5．9—10．8头／30个1m2样方，广州小斑螟种群数量与捕食性蜘蛛种群数量的比例为1：0．29～2．45，捕食性蜘蛛的比例越高，对广州小斑螟种群的控制作用就越大，害虫暴发成灾的可能性就越小。

Oligochroa cantonella is an important pest insect on community of Avicennia marina. In Guangzhou, seven generations can be finished in one year in room feeding, every generation needs 33 -35 d during first to sixth generation, and the period of winter generation was 122 d. The twigs, leaf and fruit of O. cantonella were damaged by the larvae, the most serious dried up in mass. In the community of Avicennia marina, in different are- a, the numbers of injured leaves and twigs were different. The population dynamics of O. cantonella was positively related with the numbers of the injured twigs and leaves. The annually averaged numbers of injured twigs and leaves kept 10.8 -21.5 leaves （twigs） each centiare, the annually averaged numbers of pest insects were 4.4 - 20.4 each centiare. The predaceous spider was important natural enemy to control O. cantonella, which its annual aver- aged numbers keep 5.9 - 10.8 caput each centiare. The proportion between O. cantonella and the spider was 1 ：0.29 - 2.45. The more numbers of the spiders, the higher of the control function of O. cantonella, the less possi- bility of breaking up of pest insects