1. A synergistic herbicidal composition comprising (A) flazasulfuron or a salt thereof and (B) at least one urea compound selected from the group consisting of tebutiuron, diuron and methobromuron or a salt thereof. A synergistic herbicidal composition according to claim 1, wherein the ratio in the mixture (A) to (B) is from 1: 1 to 1: 500 in a weight ratio. A synergistic herbicidal composition according to claim 1, wherein the urea compound (B) is at least one member selected from the group consisting of tebutiuron and methobromuron. A synergistic herbicidal composition according to claim 3, in which the ratio in the mixture (A) to (B) is from 1: 3 to 1: 200 in a weight ratio. A method for controlling unwanted plants or inhibiting their growth, which comprises applying a synergistically herbicidally effective amount of (A) flazasulfuron or a salt thereof and (B) at least one urea compound selected from the group consisting of tebutiuron, diuron and methobromuron, or salts, to unwanted plants or to the place where they grow. 6. The method according to claim 5, in which (A) is used in an amount of from 10 to 150 g / ha, and (B) is used in an amount of from 150 to 5000 g / ha. The method of claim 5, wherein the urea compound (B) is at least one member selected from the group consisting of tebutiuron and methobromuron. The method according to claim 7, in which (A) is used in an amount of from 15 to 100 g / ha, and (B) is used in an amount of from 300 to 3000 g / ha. A synergistic herbicidal composition comprising (A) flazasulfuron or a salt thereof and (B) diuron or a salt thereof in a ratio of (A) to (B) in a mixture of 1:22 to 1: 66.6 in a weight ratio. 10. A way to control unwanted plants or suppress their growth, which1. Синергическая гербицидная композиция, включающая (A) флазасульфурон или его соль и (B), по меньшей мере, одно соединение мочевины, выбранное из группы, состоящей из тебутиурона, диурона и метобромурона или их соли.2. Синергическая гербицидная компо
