Method for controlling undesirable organisms in a field , having the following steps of: providing an electronic map in which expected locations of undesirable organisms in the field have been entered in a geo-referenced manner; crossing the field with a machine for applying an agent for controlling the undesirable organisms , which machine comprises a supply of the agent, at least one controllable dispensing device for applying the agent and a local sensor for detecting undesirable organisms in the field , wherein the map is used to control a function of the machine in an anticipatory manner, while the local sensor is used to control the dispensing device , the function of the machine which is controlled in an anticipatory manner comprises automatically opening the dispensing device for the purpose of applying the agent to a location of the undesirable organism which is entered in the map, and the local sensor causes automatic closing of the dispensing device if the local sensor does not detect an undesirable organism at the location entered in the map, and the function of the machine which is controlled in an anticipatory manner comprises automatically reducing the advancing speed of the machine for the purpose of achieving a reduced advancing speed at the location of the undesirable organism entered in the map, and the local sensor is used to control the dispensing device there, characterized in that , when travelling in regions of the field at which no undesirable organisms are entered in the map, the machine moves at a first advancing speed which is greater than the distance (x) between the region sensed by the local sensor and the point of the field to which the dispensing device applies the agent divided by the sum of the reaction times of the local sensor and the dispensing device , and the reduced advancing speed is less than or equal to the distance (x) mentioned divided by the sum of the reaction times of the local sensor and the dispensing device . providing an electronic map in which expected locations of undesirable organisms in the field have been entered in a geo-referenced manner; crossing the field with a machine for applying an agent for controlling the undesirable organisms , which machine comprises a supply of the agent, at least one controllable dispensing device for applying the agent and a local sensor for detecting undesirable organisms in the field , wherein the map is used to control a function of the machine in an anticipatory manner, while the local sensor is used to control the dispensing device , the function of the machine which is controlled in an anticipatory manner comprises automatically opening the dispensing device for the purpose of applying the agent to a location of the undesirable organism which is entered in the map, and the local sensor causes automatic closing of the dispensing device if the local sensor does not detect an undesirable organism at the location entered in the map, and the function of the machine which is controlled in an anticipatory manner comprises automatically reducing the advancing speed of the machine for the purpose of achieving a reduced advancing speed at the location of the undesirable organism entered in the map, and the local sensor is used to control the dispensing device there, characterized in that , when travelling in regions of the field at which no undesirable organisms are entered in the map, the machine moves at a first advancing speed which is greater than the distance (x) between the region sensed by the local sensor and the point of the field to which the dispensing device applies the agent divided by the sum of the reaction times of the local sensor and the dispensing device , and the reduced advancing speed is less than or equal to the distance (x) mentioned divided by the sum of the reaction times of the local sensor and the dispensing device . <EOS>