To investigate the effect that four different nozzle types had on spray efficacy using herbicides with different modes of action.

This demonstration has highlighted the impact poor nozzle selection can have on herbicide efficacy. Generally all post emergent herbicide applications are made with the one nozzle type, as a result, less than optimal weed control may occur. It was found that selecting a nozzle with a fine droplet pattern and good coverage gave best results for contact herbicides (Brodal and Bromoxynil) and for those poorly translocated within plants (Group A herbicides). For LVE MCPA, which moves readily through the plant, coverage is not essential allowing larger droplet size nozzles to be used without losing efficacy. This is important for preventing drift, as phenoxy herbicides such as LVE MCPA are susceptible to drift. Understanding how herbicides work will allow for better nozzle selection and more cost effective weed control.