Determining developments in pesticide use: an application to the Netherlands.

Different causes of changes in pesticide use are analysed, with the situation in the Netherlands as background for empirical illustrations. The usual methodology assumes a large inventory study on pesticide use. This inventory study may contain a number of errors or rest upon incomplete information. During a certain period indicators of pesticide use are often more aggregate. Moreover, the introduction of new pesticides, the abolishing of some old ones and the fluctuation in pesticide use because of changes in weather and disease patterns make it very difficult to measure developments in pesticide use. This is, however, an important element in the targeting of the reduction of emissions. A methodology is presented which introduced, in a stepwise manner, new information within a large database to provide decision makers with relevant information. The methodology classifies different causes, such as inconsistency between different data sets, changes in the area of different crops, introduction of new and abolishing of old pesticides, developments in pesticide use and fluctuations in pesticide use. It is concluded that as a result of the importance of the 1st, 3rd and 5th categories, it is difficult to give a clear indication of the development in pesticide use and therefore the fulfilment of environmental targeting in volume of active ingredient