本文敘述日本雜草防除概況。殺草劑在日本推荐使用始於1965年。1960年在耕地使用之殺草劑總值約600萬美金，但到1990年則高達7.8億美金，佔所有農藥金額的三分之一。至於水田殺草劑使用面積由1960年之80萬公頃，增加至1990年之4億公頃；這個數值表示同一塊水田，在一個期作內使用2或3次殺草劑。在1950年之水田除草每公頃需500工時，大量使用殺草劑後，到1990年減少至2工時。由於水稻栽培方法之改進及殺草劑的連續使用，造成多年生雜草防治上的問題。在1989年已登記之殺草劑種類有150種，其中96種使用在水田，而近年來藥劑的開發，著重在以sulfonyl urea類並列一次施用方式的最佳組合的研究，以取代土壤處理方式。目前殺草劑所面臨的問題為在作物及土壤中之殘留、水的污染、有效成份的降低及改進藥劑之施用方法，以有效防治多年生草。

This report summarized for weed control status in Japan.Weed control in Japan was not treated as science before 1950.Practical use of herbicide was commenced after 1965. In 1960,total value for herbicides was about one billion yen (6 millionUS$) in arable land and reached up about 117 billion yen(780 million US$) in 1990. This value corresponded one-thirdof that for a11 pesticide used in Japan. On the other hand, theherbicide usage on paddy field was 0.8 million hectare in 1960,but in 1990 the area increased about 400 million hectare. Thismeans the herbicide used area become two or three hundredper cent in total paddy field owing to the 2 -...- 3 times treatmenton the same field. The weeding labor required 500 hrsper hectare in 1950. However, due to labor shortage in farmer,gradually, weeding labor with using herbicide was accomplishedwhich reduced to 2 hrs per hectare in 1990. Even with herbicidedeveloped in paddy field, it occured a problem with theincrease of perennial weeds. The reason are the change of ricecultivation and continual herbicide use. In 1989, registered herbicidesare about 150 and among them 96 in paddy field, andincrease in combination product based on sulfonyl urea andone shot application method instead of soil treatment recently.Nowadays, it proposed the problem of situation on herbicide,for instance, residue in crop and soil, water pollution, low rateof active ingredient, improvement of application and effectivecontrol for perennial weeds.