PROBLEM TO BE SOLVED: To provide a novel noxious organism control agent, particularly a bactericidal agent and a nematicidal agent.SOLUTION: The present invention provides an N-alkenyl-substituted amide compound represented by formula (I) or a salt of the compound, and a noxious organism control agent comprising them. In the formula, Grepresents a structure represented by G-1a, G-3a, G-27a or the like; Xrepresents a halogen atom, difluoromethyl, trifluoromethyl or the like; Yrepresents a halogen atom or the like; Yrepresents a hydrogen atom, a halogen atom, methoxy or the like; Yrepresents a halogen atom, trifluoromethyl or the like; Yrepresents a hydrogen atom, a halogen atom or the like; Rand Rindependently represent a hydrogen atom, a halogen atom, methyl, or the like; Rand Rindependently represent a hydrogen atom, methyl or the like; and Rrepresents a hydrogen atom or the like.【課題】 新規な有害生物防除剤、特に殺菌剤及び殺線虫剤を提供する。【解決手段】 式(I):【化1】[式中、G1はG1-1a、G1-3a、G1-27a等で表される構造を表し、Wは酸素原子等を表し、X1はハロゲン原子、ジフルオロメチル、トリフルオロメチル等を表し、Y1はハロゲン原子等を表し、Y2は水素原子、ハロゲン原子、メトキシ等を表し、Y3はハロゲン原子、トリフルオロメチル等を表し、Y4は水素原子、ハロゲン原子等を表し、R1及びR2は各々独立して水素原子、ハロゲン原子、メチル等を表し、R3及びR4は各々独立して水素原子、メチル等を表し、R5は水素原子等を表す。]で表されるN-アルケニル置換アミド化合物又はその塩、及びそれらを含有する有害生物防除剤。【選択図】 なし