异色瓢虫不同地理种群对拉萨设施蔬菜桃蚜的捕食功能研究

Control Potential of Different Geographic Populations of Harmonia axyridis on Myzus persicae in Greenhouses of Lhasa

为明确异色瓢虫对桃蚜的捕食潜能及不同地理种群异色瓢虫捕食能力的差异,本研究以辣椒为寄主植物,研究了异色瓢虫各龄幼虫和成虫对桃蚜的捕食功能反应、异色瓢虫4龄幼虫在不同益害比下的捕食作用及不同地理种群异色瓢虫4龄幼虫的捕食能力.结果表明,异色瓢虫各虫态对桃蚜的捕食功能反应符合Holling II反应模型,对桃蚜的捕食量有明显差异,在相同桃蚜密度下,日最大捕食量按从高到低依次为4龄幼虫(250.00头)、雌成虫(166.67头)、雄成虫(142.88头)、3龄幼虫(62.50头)、2龄幼虫(13.33头)、1龄幼虫(3.77头).当桃蚜密度均为500头时,随着异色瓢虫数量的增加,其捕食量呈现先增大后减少的趋势.当瓢虫与桃蚜数量之比为6∶500时,其最大日捕食量为443.10头,最佳益害比例为1∶83.通过比较3个不同地理种群的4龄异色瓢虫日均捕食量,发现林芝4龄异色瓢虫在不同蚜虫密度下显著高于沈阳和福建4龄幼虫,而福建和沈阳4龄幼虫之间差异不明显.

To clarify the predation potential of Harmonia axyridis on Myzus persicae and the difference in predation ability of different H.axyridis geographic populations,this research,with pepper as the host,evaluated the predation functional responses of each instar larvae and adults of H.axyridis on M.persicae,the predatory capacity 4-instar larvae with different ratios of H.axyridis to M.persicae,and compared the predatory capacity of different geographic populations of H.axyridis.The results indicated that the predation functional responses of H.axyridis could be described by the HollingII model,and the predatory capacities varied conspicuously in different instars and geographic populations.Under the same density of M.persicae,the maximum daily predatory number of H.axyridis was ranked as following:4-instar larvae(250.00),female adults(166.67),male adults(142.88),3-instar larvae(62.50),2-instar larvae(13.33)and 1-instar larvae(3.77).When density of M.persicae was 500,with the increase of the number of H.axyridi,its predatory capacity first increased and then decreased.Based on quadratic regression,when the ratio of H.axyridis to M.persicae was 6∶500,the maximum predatory number was 443.10,the best ratio was 1∶83.In a comparison of the 4-instar larvae of the three origin locations studied,Linzi 4-instar larvae were found to have significantly higher average daily predatory number than those originating from Shenyang or Fujian,however,there was no significant differences between Fujian and Shenyang 4-instar larvae.