浙南地区菜田蜘蛛自然种群消长动态及农药对其毒性

Population fluctuation of spiders in vegetable fields and toxicity of insecticides to them in South Zhejiang

通过 1999— 2 0 0 0年的系统调查 ,初步明确浙南地区菜田蜘蛛种类和发生趋势 ,发现其主要优势种为八斑球腹蛛和草间小黑蛛 ,分别占菜田蜘蛛总数的 4 0 .74 %和 30 .93%。栖住场所数量大小选择趋势为绿花菜≥花菜 >甘蓝 =大白菜 >小白菜。菜田蜘蛛一般在 12月底开始越冬 ,露地菜田 2月初少量开始活动 ,5月中旬至 10月初数量一直保持在较高的水平 ,11月形成一个明显发生高峰。菜田蜘蛛的时间生态位宽度和生态位重叠度较大 ,与菜田害虫在时间上具有同步性 ,表明菜田蜘蛛对菜田害虫具有较强的控制作用。试验还表明 ,抑太保、BT等 (生物防治区 )对蜘蛛杀伤力较小 ,乐斯本、锐劲特、氰戊菊酯等 (化学防治区和农民自控区 )对蜘蛛杀伤力较强。

In 1999-2000, species and population dynamics of spiders in vegetable fields and effects of control practices were investigated in South Zhejiang. Results showed that dominant species of spiders were Theridion octomaculatum and Erigonidium graminicola, respectively accounting for 40.74% and 30.93% of all spiders. Its suitable place were in the following order of preference: Italica Plenk≥cauliflower=cabbage>Chinese cabbage>pakchoi. Spiders usually overwintered in December, and a small number of spiders began to active in February in the field. The number of spiders kept high from mid May to early October, and appeared to be a clear peak in November. Time niche breadth and niche overlap of spiders were large, synchronized with insect pests of vegetable, which indicated that the spiders had a great control effect on insect pest in vegetable fields . Results also showed that effect on spiders differed among three control practices (biological control, chemical control and farmer decision). BT and chlorfluazuron(biological control ) had a less killing effect on spiders ,but losban ,fipronil and fenvalerate (chemical control and farmer decision) were more Toxic to them.