Department of Plant Pathology, University of California, Davis, CA 95616, USA.
J Econ Entomol. 2011 Aug;104(4):1323-8. doi: 10.1603/ec10415.
Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major horticultural pest and an important vector of plant viruses in many parts of the world. Methods for assessing thrips population density for pest management decision support are often inaccurate or imprecise due to thrips' positive thigmotaxis, small size, and naturally aggregated populations. Two established methods, flower tapping and an alcohol wash, were compared with a novel method, plant desiccation coupled with passive trapping, using accuracy, precision and economic efficiency as comparative variables. Observed accuracy was statistically similar and low (37.8-53.6%) for all three methods. Flower tapping was the least expensive method, in terms of person-hours, whereas the alcohol wash method was the most expensive. Precision, expressed by relative variation, depended on location within the greenhouse, location on greenhouse benches, and the sampling week, but it was generally highest for the flower tapping and desiccation methods. Economic efficiency, expressed by relative net precision, was highest for the flower tapping method and lowest for the alcohol wash method. Advantages and disadvantages are discussed for all three methods used. If relative density assessment methods such as these can all be assumed to accurately estimate a constant proportion of absolute density, then high precision becomes the methodological goal in terms of measuring insect population density, decision making for pest management, and pesticide efficacy assessments.
西方花蓟马，Frankliniella occidentalis (Pergande)（缨翅目：蓟马科），是世界许多地区的主要园艺害虫和重要植物病毒载体。由于蓟马具有正趋触性、体型小和自然聚集的特点，评估蓟马种群密度以支持害虫管理决策的方法往往不准确或不精确。两种已建立的方法，即花敲击法和酒精冲洗法，与一种新的方法，即植物干燥结合被动诱捕法进行了比较，以准确性、精密度和经济效益作为比较变量。所有三种方法的观察准确性均统计学上相似且较低（37.8-53.6%）。就工时而言，花敲击法是最经济的方法，而酒精冲洗法是最昂贵的方法。相对变化表示的精密度取决于温室内部的位置、温室长凳上的位置和采样周，但通常花敲击法和干燥法的精密度最高。以相对净精密度表示的经济效益，花敲击法最高，酒精冲洗法最低。讨论了所有三种方法的优缺点。如果可以假定相对密度评估方法（如这些方法）都可以准确估计绝对密度的恒定比例，那么在衡量昆虫种群密度、害虫管理决策和农药功效评估方面，高精度就成为方法学目标。
