PROCESS DRIVEN MODELS FOR SPRAY RETENTION BY PLANTS

The aim of this project was to investigate and develop physical models of the process of spray retention on plants. By developing a greater understanding of the physical processes involved in spray retention it is then possible to tailor spray formulations that will be retained better on various types of plant leaves. This has great environmental and cost benefits as it is then possible to use less active chemicals to achieve the same level of uptake by the plant. Different aspects of the retention process were considered including the trajectory of the spray on leaving the nozzle; a droplet-leaf collision model allowing for bounce, shatter and retention of the droplets on the leaf surface; overall retention and runoff of spray as it accu-mulates on the leaf surface; and a plant canopy model to describe the interception of the spray within the plant canopy. 1