Summary.The ‘Vibrajet’ nozzle is designed to produce relatively large droplets with ‘low drift’ characteristics. This system was evaluated for the overall application of paraquat, diquat and morfamquat in a number of agricultural situations in comparison with a fan jet. The biological efficiency achieved with the ‘Vibrajet’ nozzle was of the same order as that of the fan jet at the rates of application of the herbicides currently recommended in the United Kingdom. Five variables which affect the field performance of a spray system were investigated: volume of spray applied, concentration of wetter in the spray, rate of chemical applied, spray pressure and size of orifice. Changes in these factors made little improvement to the biological efficiency of the ‘Vibrajet’ nozzle.Comparaisnn de la buse ‘Vibrajet’ et d'une bitse pinccau pom Vapplication generalisee des herbi