Schwartz A M, Paskewitz S M, Orth A P, Tesch M J, Toong Y C, Goodman W G
Department of Entomology, University of Wisconsin-Madison 53706, USA.
J Am Mosq Control Assoc. 1998 Mar;14(1):78-82.
The sedge Cyperus iria, a common weed in rice, contains large amounts of the insect hormone (10R) juvenile hormone III (JH III). Given its widespread distribution in Asia and Africa, we examined the possibility that C. iria could be used as a safe, inexpensive, and readily available mosquito larvicide. Plants of varying ages were harvested and leaves tested for lethal effects on larvae of the yellow fever mosquito, Aedes aegypti. The median lethal doses (LD50s) for frozen leaves from 1- and 2-month-old plants were 267 and 427 mg/100 ml of water, respectively. Leaves from 1-month-old C. iria contained 193 micrograms JH III/g fresh weight, whereas leaves from 2-month-old plants contained 143 micrograms JH III/g fresh weight. Larval sensitivity to the plant differed with age; 4-day-old larvae displayed the greatest mortality followed in decreasing sensitivity by larvae 5, 6, 3, and 2 days old. Six Cyperus species (C. albostriatus, C. alternifolius, C. esculentus, C. iria, C. miliifolius, and C. papyrus) of similar developmental stage were assayed for JH III content. Only C. iria was found to contain significant levels of JH III.
莎草科植物节节草是稻田中常见的杂草，含有大量昆虫激素（10R）保幼激素III（JH III）。鉴于其在亚洲和非洲广泛分布，我们研究了节节草用作安全、廉价且易于获取的杀蚊幼虫剂的可能性。采集不同年龄的植株，检测其叶片对黄热病蚊种埃及伊蚊幼虫的致死作用。1月龄和2月龄植株冷冻叶片的半数致死剂量（LD50）分别为267和427毫克/100毫升水。1月龄节节草叶片每克鲜重含193微克JH III，而2月龄植株叶片每克鲜重含143微克JH III。幼虫对该植物的敏感性因年龄而异；4日龄幼虫死亡率最高，其次是5、6、3和2日龄幼虫，敏感性依次降低。对发育阶段相似的6种莎草属植物（白纹莎草、风车草、香附子、节节草、细叶莎草和纸莎草）进行了JH III含量测定。仅发现节节草含有显著水平的JH III。
