烟田释放七星瓢虫对烟蚜的防治效果

The Control and Ecological Effect of Coccinella septempunctata on Myzus persicae in Liangshan Tobacco Field

为明确七星瓢虫释放对烟田烟蚜的防治效果及其初步生态效应,本研究开展了凉山烟田七星瓢虫释放及烟田害虫和天敌种群消长调查试验.结果表明,释放七星瓢虫对烟田烟蚜防治具有一定的防治效果,释放后第1 d的校正防效可达62.88%,之后第2 d、第3 d逐步下降,分别为50.77%和39.42%.定殖扩散试验结果表明,七星瓢虫成虫在烟田释放后扩散能力较强,释放后第1 d调查时,在目标烟株上的定殖率仅为50.00%,而第2 d、第3 d调查时在目标烟株上的定殖率均成为0.种群消长调查结果表明,目标烟田害虫以无翅烟蚜的数量最高,平均单株蚜量可达15.06头/株,其次是有翅烟蚜,平均单株蚜量为1.67头/株,天敌种类以烟蚜茧蜂和食蚜蝇为主.各种类害虫及天敌数量在瓢虫释放后均表现出先减少后逐步增多的趋势,其中以无翅烟蚜、烟蚜茧蜂成虫和僵蚜在第1 d调查时减弱趋势较为明显,第1 d调查时无翅烟蚜平均单株蚜量下降到7.05头/株.

In order to reveal the control and ecological effect of Coccinella septempunctata on tobacco aphids, the population and quantity of pests and natural enemies in tobacco fields were investigated. The results showed that the release of C. septempunctata had a certain effect on control of tobacco aphids. The corrected mortality rate reached 62.88% on the first day after release, and gradually decreased to 50.77% and 39.43% on the second day and third day, respectively. The results of diffusing behavior observation showed that the adult C. septempunctata had strong dispersal ability. The colonization rate of C. septempunctata in the target tobacco plant was 50.00% at 1 st day after release, and 0 at the 2 nd and 3 rd day after release. The population dynamics of all kinds of pests and natural enemies before and after the release were preliminarily determined. The number of wingless aphids per plant was the highest among all the pests with average 15.06 aphids per plant, followed by the winged aphids with average 1.67 aphids per plant. The main natural enemies were Aphidius gifuensis Ashmead and Syrphidae. The number of pests and natural enemies showed a trend of decreasing first and then increasing gradually. The decrease of wingless tobacco aphid, tobacco aphid cocoon bee adult and stiff aphid was obvious on the first day of investigation, and the average number of wingless tobacco aphids per plant decreased to 7.05 heads per plant.