The Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (Coleoptera: Curculionidae) antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), has been used since 2000 to protect high-value trees and stands throughout western North America. Operational treatments involve placing individual releasers on a 12 m × 12 m grid throughout the area to be protected. In this study, six widely spaced trap lines were established with aggregation attractant–baited traps located 1, 3, 9, 27, and 81 m from a location where an operational MCH release device was alternately either present or absent, and changes in catches caused by the MCH device were assessed at all distances. Trap catches were suppressed by about 70% at one and three metres, by 50% at nine metres, by 30% at 27 m, and not at all at 81 m. Inhibition by the MCH device varied with distance (m) from the source according to the function 0.79 − 0.092x0.51 (R2 = 0.986). Decline of attractant inhibition with distance from the MCH device was much less steep than would have been expected if catch inhibition had varied directly with the average airborne concentration of MCH.

道格拉斯冷杉甲虫（Dendroctonus pseudotsugaeHopkins（鞘翅目：Curculionidae）抗聚集信息素3-methylcyclohex-2-en-1-one（MCH）自2000年以来一直用于保护高价值的树木，并在整个北美西部屹立。操作处理包括将单个释放器放置在整个要保护区域的12 m×12 m网格上。在这项研究中，建立了六个间隔较大的诱集线，这些诱集诱饵诱集的诱集装置位于距离交替出现或不存在可使用的MCH释放装置的位置分别为1、3、9、27和81 m的诱集诱饵诱集装置，由MCH设备在所有距离进行评估。陷阱捕获在第1和第3米处被抑制了约70％，在九米处被抑制了50％，在27 m处被抑制了30％，而在81 m处则没有被抑制。MCH设备的抑制作用根据功能0与源之间的距离（m）而变化。× 0.51（R 2 = 0.986）。诱剂抑制作用随距MCH装置的距离而下降的幅度要比如果捕获抑制作用随MCH的平均空气传播浓度直接变化而预期的陡度要小得多。