1. Field of the Invention
The invention is in the technical field of crop protection products which can be employed against harmful plants, for example in crop plants, and which comprise, as active compounds, a combination of at least two specific herbicides.
2. Description of Related Art
The document EP-A-131258 discloses sulfonylureas and their salts and also their use as herbicides and/or plant growth regulators.
The efficacy of these herbicides against harmful plants in the crop plants is at a high level, but depends in general on the application rate, the formulation in question, the harmful plants or spectrum of harmful plants to be controlled in each case, the climatic conditions, the soil conditions and the like. Another criterion is the duration of action, or the breakdown rate of the herbicide. If appropriate, changes in the sensitivity of harmful plants, which may occur upon prolonged use of the herbicides or within geographic limitations, must also be taken into consideration. The compensation of losses in action in the case of individual harmful plants by increasing the application rates of the herbicides is only possible to a certain degree, for example because such a procedure frequently reduces the selectivity of the herbicides or because the action is not improved, even when applying higher rates. In some cases, the selectivity in crops can be improved by adding safeners. In general, however, there remains a need for methods to achieve the herbicidal action with a lower application rate of active compounds. Not only does a lower application rate reduce the amount of an active compound required for application, but, as a rule, it also reduces the amount of formulation auxiliaries required. It both reduces the economic input and improves the ecological compatibility of the herbicide treatment.
One possibility of improving the application profile of a herbicide can consist in combining the active compound with one or more other active compounds. However, the combined use of a plurality of active compounds frequently causes phenomena of physical and biological incompatibility, for example a lack of stability in a coformulation, decomposition of an active compound, or antagonism of the active compounds. What is desired are, in contrast, combinations of active compounds having an advantageous activity profile, high stability and, if possible, a synergistically improved action, which allows the application rate to be reduced in comparison with the individual application of the active compounds to be combined.