Disclosed is a composition when used as a herbicide, comprising an oily extract as an active ingredient. The oily extract is obtained by: a) cooling steam generated during a drying step of lumber from trees belonging to the order Pinales, or b) steam distillation of lumber from trees belonging to the order Pinales, or c) hot water extraction of lumber from trees belonging to the order Pinales. Examples of trees belonging to the order Pinales include those belonging to the to the genus Cryptomeria, Thuja, Thujopsis, Chamaecyparis, Cupressus or Juniperus (belonging to the family Cupressaceae) or to the genus Picea, Tsuga, Cedrus, Pseudotsuga, Larix, Pinus or Abies (belonging to the family Pinaceae). Also disclosed is a weed control method, comprising application of the herbicide composition to target weeds.
