Introduction of pyrethrum flowers (130 years in Japan)

Pyrethrum, Chrysanthemum tanacetum subsp. cinerariaefolium, is native to the Dalmatian region of former Yugoslavia. It was introduced to Japan in 1885. Eiichiro Ueyama, the founder of Dainihon Jochugiku Co., Ltd., obtained seeds of pyrethrum in 1886 from H.E. Amoore, a British plant trader, for industrial purposes. After starting its cultivation in Wakayama prefecture, he promoted its plantation throughout the country and popularized it for overseas exportation. Similar to the Dalmatian region, pyrethrum was initially utilized as a powder in Japan. Mosquito incense, developed by Eiichiro Ueyama in 1890, was in the shape of a stick and had a burning time of approximately 40 min. The mosquito stick was subsequently improved and developed into a coil type with a burning time of 7-8 h, equivalent to the sleeping time of humans. Eiichiro Ueyama also improved the method of growing pyrethrum flowers and had his methods published in a book. Pyrethrum consequently became the main source of household insecticides such as mosquito coils, and Japanese pyrethrum reached its peak production of 13,000 tons of dried flowers per annum in 1935. The structural elucidation of natural pyrethrins contained in pyrethrum has led to the development of a number of useful synthetic pyrethroids. Continuing with this success, aerosol products effective for various kinds of insects are now available. Other products such as mosquito killer mats, liquid-type mosquito killers, and battery-powered devices have also been developed in Japan. Although the active ingredients in mosquito coils have mostly shifted from pyrethrum to the synthetic pyrethroid allethrin, they have retained the original shape developed by Eiichiro Ueyama and have been used worldwide for more than 110 years. Thus, the technology of the mosquito incense stick has been registered at the National Museum of Nature and Science as one of the scientific technologies developed in Japan.