Leaf wall area and leaf area in cucumber, eggplant, sweet pepper and tomato grown in greenhouses in S witzerland

Various methods for the harmonization of the registration of crop protection products and dose adjustments in high growing crops have been discussed over many years. The leaf wall area ( LWA ) method has been known for some years already but it has received renewed attention due to a proposal by the E uropean agrochemical manufacturing industry for harmonizing the dose expression in view of the new zonal registration system in the EU . The LWA method appears not only suitable for fruit trees and vineyards, but may also prove a simple and widely accepted method for dose adjustments in high growing vegetable crops particularly in greenhouses. This paper provides a dataset on leaf wall area and leaf area development for a selection of commercially grown cucumber, eggplant, sweet pepper and tomato varieties in S witzerland. Relationships between leaf wall area and leaf area have been established. A tentative product dose adjustment to growing vegetable crops in greenhouses is given for S witzerland. Biological efficacy trials will be required to validate the LWA method.