Abstract
The Research Centre Laimburg (South Tyrol, Italy) has been conducting trials on the use of plant protection products, applied via overhead irrigation, for apple scab control for more than 10 years. High levels of efficacy were achieved in several trials carried out in South Tyrol and in other fruit growing areas. However, in most countries it is still not clear whether a multi-functional overhead irrigation, developed for frost protection and irrigation, can also be used for plant protection. Different technical details such as pump pressure, sprinkler type, nozzle size, irrigation pipeline design and finally droplet size are under discussion. It has not yet been established whether and to which extent (as during the application with conventional spray equipment) small driftable droplets are produced by using the overhead irrigation system. This study aimed at determining the droplet size spectrum of different circle sprinklers.