人工投放七星瓢虫在烟田的定殖扩散能力

Colonization and Spreading Ability of Artificially Released Coccinella Septempunctata in Tobacco Fields

为了探索不同环境因子对人工投放的七星瓢虫在烟田定殖和扩散能力的影响,2019—2020年于四川省凉山彝族自治州冕宁县回龙镇,对七星瓢虫的不同虫态在烟田的孵化、扩散及留置规律开展了研究。结果表明,释放于烟株中部的七星瓢虫卵块孵化率为83.3%,极显著高于释放于烟株顶部和底部的卵块,与室内卵块没有显著性差异;阴天释放的卵块孵化率为91.1%,显著高于雨天释放的卵块,与室内和晴天的卵块没有显著性差异。1龄幼虫与靶标烟株的距离大于0.55 m则不能扩散至靶标烟株,低龄幼虫在靶标烟株上的停留时间达到7 d。阴天释放的成虫在靶标烟株上的停留时间达到40 h;成虫扩散距离达到150 m。综上所述,阴天是释放七星瓢虫卵和成虫的较优天气,蚜虫发生烟株中部是释放七星瓢虫卵块的较优部位。

In order to explore the effects of different environmental factors on the ability to colonize and spread of Coccinella septempunctata artificially released in tobacco fields, in 2019—2020, in Huilong Town, Mianning County, Liangshan Yi Autonomous Prefecture, Sichuan Province, research was carried out to analyze the hatching, spreading and retention of different insect stages of C. septempunctata in tobacco fields. The results showed that the hatching rate of egg masses released in the middle of the tobacco plants was 83.3%, which was significantly higher than the hatching rate released on the top and the bottom of the tobacco plants, and but not significantly different from the hatching rate of the indoor experiments. The hatchability of egg masses released in cloudy days was 91.1%, significantly higher than rainy days, and but not significantly different from that of in indoor environments and in sunny days. When the distance between the first larvae and the target tobacco plant is greater than 0.55 meters, the insect couldn’t spread to the target tobacco plant, and the young larvae stayed on the target plant for 7 days. The residence time of adults released in overcast days reached 40 h on the target tobacco plants. Adult dispersal distance reached 150 m. In conclusion, cloudy days are the best weather for releasing C. septempunctata, and the middle part of the tobacco plants is the best part for releasing C.septempunctata eggs.