Dose Rate Expression-Need for Harmonization and Consequences of the Leaf Wall Area Approach; [Dosiereinheiten - Notwendigkeit zur Harmonisierung und der Konsequenzen des Laubwandflächenmodells]

Dose expressions are highly variable within the European Union. Recommended doses in high growing crops are expressed in various ways on product labels. Therefore it is necessary to harmonize the dose expression in high crops. In future one model should be favored, preferably the leaf wall area (LWA) approach. The doses in the LWA model are expressed in kg or L per 10. 000 m 2 leaf wall area. This is the basis for canopy-adjusted dose determination in all high crops. The leaf wall area (LWA) is a function of the canopy height and the row spacing. The canopy height will be defined as the average distance from the highest leaf to the deepest leaf of a tree. In this publication first results of the determination of LWA in different German fruit farms with commercial apple plantations are presented and discussed. The LWA as well as the incremental growth depends on the rootstocks and the varieties. The measured figures vary from approx. 8000 m 2 for new planting to approx. 19000 m 2 for older orchards. © 2012 Springer-Verlag.