Mundal Kirk D, Brewer Gary J
Department of Entomology, North Dakota State University, Hultz Hall, 1300 Albrecht Blvd., Fargo, ND 58105, USA.
J Econ Entomol. 2008 Jun;101(3):969-75. doi: 10.1603/0022-0493(2008)101[969:ubsmlt]2.0.co;2.
The banded sunflower moth, Cochylis hospes Walsingham (Lepidoptera: Tortricidae), is an important economic pest of sunflower in the Upper Great Plains of North America. Economic losses due to reductions in seed number, weight, and quality can be significant. Previously, the potential for economic losses were estimated by sampling for adult moths. However, sampling for moths can be difficult and inaccurate. An alternative is to sample for banded sunflower moth eggs, which can be accurately counted in the field by using a binocular 3.5 headband magnifier. The egg counts are used to calculate the economic injury level (EIL) (EIL = C/VWPK), where C is the cost of treatment per unit area, V is the crop market value per unit of weight, W is the slope of the regression between banded sunflower moth egg densities and weight loss per plant, P is a term for plant population per unit area, and K is the control treatment efficacy. Estimates of populations of banded sunflower moth eggs are taken from the center of 400-m spans along all field sides. From these samples and the calculated EIL, a map of the extent of the economically damaging banded sunflower moth population throughout the field is made using economic distance; ED = e ( ( (EIL/E)-1.458)/-0.262). Economic distance estimates the distance an economic population extends into the field interior along a transect from the sampling site. By using egg samples to calculate the EIL and mapping the distribution of economic populations throughout a field, producers can then make more effective pest management decisions.
带状向日葵螟（Cochylis hospes Walsingham，鳞翅目：卷蛾科）是北美大平原上游地区向日葵的一种重要经济害虫。因种子数量、重量和质量下降造成的经济损失可能相当可观。此前，经济损失的可能性是通过对成虫进行抽样来估计的。然而，对成虫进行抽样可能既困难又不准确。另一种方法是对带状向日葵螟的卵进行抽样，通过使用双目3.5头带式放大镜可以在田间准确计数。卵的计数用于计算经济损害水平（EIL）（EIL = C/VWPK），其中C是每单位面积的防治成本，V是每单位重量的作物市场价值，W是带状向日葵螟卵密度与单株重量损失之间回归的斜率，P是单位面积的植株数量项，K是防治处理的效果。带状向日葵螟卵的种群估计取自沿田间所有边缘400米跨度的中心。根据这些样本和计算出的EIL，利用经济距离绘制出整个田间经济上有损害的带状向日葵螟种群范围的地图；ED = e ( ( (EIL/E)-1.458)/-0.262)。经济距离估计经济种群沿着从采样点出发的样带向田间内部延伸的距离。通过利用卵样本计算EIL并绘制整个田间经济种群的分布图，生产者随后可以做出更有效的害虫管理决策。
