Relevance of the deposit structure for the uptake and bio-efficacy of diquat, as monitored by the spatially resolved chlorophyll fluorescence

- The relation between deposit pattern and bio-efficacy was studied.
- Chlorophyll fluorescence technique is suitable for monitoring uptake of diquat.
- Surfactant affected diquat deposit on difficult-to-wet, but not on easy-to-wet leaf.
- Compact deposit was most efficient in reducing Fv/Fm and dessicating the tissue.