Reduced span spray – Part 1: Retention

Maximising treatment efficiency for a given target lies mainly on depositing a maximum
part of the spray volume within an optimal droplet size range, which has to be as narrow
as possible to reduce retention variability and drift issues. The present work focuses on
exploring the effect of span factor of the droplet size distribution on the final retention by a
3D target plant using a modelling approach with the final aim of guiding the development
of a reduced span nozzle (Reduced span spray – Part 3: Design of narrow span nozzle).
Five droplet size spans have been tested for three VMD and three wetting scenarios on the
same 3D plant architecture. Performing a screening of the different parameters involved in
spray retention with a modelling approach based on a deeper understanding of leaf/droplet
interactions is a valuable approach for highlighting the optimal droplet size distribution
maximising droplet retention for a given target/formulation combination.