Driven by 25 years of Danish, political 'pesticide action plans', aiming at reducing the use of pesticides, a Danish Decision Support System (DSS) for Integrated Weed Management (IWM) has been constructed. This online tool, called ‘IPMwise’ is now in its 4th generation. It integrates the 8 general IPM-principles as defined by the EU.

In Denmark, this DSS includes 30 crops, 105 weeds and full assortments of herbicides. Due to generic qualities in both the integrated agro-biological models and in the IT setup, this DSS concept is currently being customized and validated for release also in Norway, Germany and Spain.

In these countries, results from field validation experiments with this DSS show that recommendations are sufficiently, agronomically robust, and has a yet unexploited potential for reducing the use of herbicides of 20-40%, as compared to references.

These potentials arise from exploitation, mainly of the following conditions: 1) weeds are unevenly distributed in time and space, 2) a complete weed kill is never required, 3) some weed species can be controlled sufficiently by down to 10% of a registered herbicide dose rate. In addition, the DSS can optimize the composition of 2–4-way tank-mixtures and thereby offer recommendations for a wide range of weed infestations.

The lack of implementation and exploitation has been thoroughly investigated in sociological studies, where farmer’s reluctance against manual weed scouting was identified as a dominating obstacle.

In a Danish project with the acronym name 'RoboWeedMaPS' (2017-20), these challenges are addressed by use of manual/automatic analyses of weed infestations, as detected from pictures and structured as required by ‘IPMwise’.

Automated weed image acquisition and semi-automated weed annotation was used to feed ‘IPMwise’, where herbicide recommendations on herbicide application were achieved on three levels i.e. field level, on/off application in points, and full precision variable dose. The results demonstrated the potential savings of the three strategies compared to the farmers actual herbicide application, which in a closer examination by ‘IPMwise’ turned out to have unsatisfactory low efficacy on some important weeds. The result was transferred to an herbicide application map and the spatial variability was analyzed and evaluated. This showed a potential of 61% reduction of herbicide cost by changing decision making from the field level to a 10 x 10 m grid.