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为明确烟叶上释放斯氏钝绥螨防治烟蓟马的最佳释放比例和部位,本文研究了6个不同比例和3个不同部位释放斯氏钝绥螨后烟蓟马的种群变化。结果表明:按益害比10∶1释放斯氏钝绥螨在较短时间内即能有效控制烟蓟马,释放10 d后,烟蓟马的数量即下降到8.33头/株,20 d后下降到2.67头/株,40 d后烟蓟马种群消失。10 d后的相对防治效果达71.26%,20 d后达90.79%。在烟叶的中部、下部和基部释放斯氏钝绥螨均能有效控制烟蓟马。建立释放10 d后6个比例下烟蓟马的死亡率与天敌数量的关系方程,y=106.857×e-104.257/x,计算出烟蓟马的死亡率达到50%的释放数量为LT50=137头/株,即按益害比4.6∶1释放;死亡率达到90%的释放数量为LT90=607头/株,即按益害比20.2∶1释放。以释放比例为益害比10∶1为例,建立了烟蓟马的死亡率与时间的关系方程y=109.689×e-4.532/x,计算出释放斯氏钝绥螨后烟蓟马的死亡率达到50%的时间LD50=5.8 d,死亡率达到90%的时间为LD90=22.9 d。本文为利用斯氏钝绥螨防治烟蓟马提供依据。
In order to clarify the optimal release rate and location of A. thrips released from tobacco leaves, this paper studied the population dynamics of Thrips tabaci after six different proportions and three different parts were released. The results showed that the removal rate of A. thuringiensis was controlled within a relatively short period of time at the ratio of 10: 1, and the number of tobacco thrips decreased to 8.33 after 10 days of release. After 20 days Down to 2.67 per plant, 40 days after the thrips population disappeared. The relative control effect reached 71.26% after 10 days and 90.79% after 20 days. Thrips tabaci can be effectively controlled by the release of A. fruticosa in the middle, lower and basal leaves. The establishment of the relationship between the mortality rate of Thrips tabaci and the number of natural enemies at the six ratios after 10 days of release was y = 106.857 × e-104.257 / x, and the number of deaths reaching 50% of the thrips was LT50 = 137 Head / strain, that is, released according to the benefit ratio of 4.6: 1; and the release rate of 90% of the death rate was LT90 = 607 heads / strain, that is, released according to the benefit ratio of 20.2: 1. Taking the ratio of release to benefit ratio of 10: 1 as an example, the relationship between the mortality rate and the time of Thrips tabaci was established. The equation y = 109.689 × e-4.532 / x, and the death of Thrips tabaci was calculated. The rate of 50% of the time LD50 = 5.8 d, the mortality rate of 90% of the time for the LD90 = 22.9 d. This article provides a basis for the prevention and control of Thrips tabaci by A.spersensis.