The reduction depended on the amount of tansy planted in the fields.
减少的数量取决于种植的艾菊的数量。
Studies conducted later in a laboratory show that tansy can produce a natural chemical that keeps the potato beetle at a distance.
迟些实验室中的研究显示艾菊产生了一种能够让薯虫保持距离的自然化学物品。
A: That works, but planting things like spearmint, southernwood, and tansy could both beautify your yard and deter your invaders.
安:那是有用的,不过种一些植物,像绿薄荷、青蒿和艾菊,不但美化你的院子,更可以抵挡你的入侵者。
For example, Colorado potato beetles do not like tansy because of the strong smell of his herb.
比如,科罗拉多薯虫不喜欢艾菊,因为艾句的叶子有强烈的味道。