A generic approach to improving spray coverage

Summary

Objectives

To ensure that grape growers can achieve good coverage and maximum efficacy with agricultural plant-protection products and to assess Drift Reduction Technologies (DRTs) to minimise spray drift potential. 

Background

Pesticide application technology underpins all rural industries in Australia. Until recently it was an area of agricultural science that operated from research that was mostly conducted several decades ago. There has been very little research in new spray technology and although most spray applicators have some basic accreditation there is an urgent need for rigorous research to improve spray practices in Australian viticulture. Information in the literature shows that when vineyards are sprayed, up to 60% of the applied material can end up on the ground rather than on the canopy. Also, there are challenges in achieving uniform coverage on the target without off-target wastage of product. The project will address these issues and show how to avoid product wastage by spray adjustment for the canopy and spray optimisation for efficacy.

Research approach

Wind tunnel experiments will be conducted at the University of Queensland.  This facility is equipped with laser-diffraction instruments, a copper-vapour laser imaging instrument and a phase-Doppler particle analyser. All droplet sizing work will be conducted using these instruments and a number of spray nozzle types, nozzle pressures and chemical formulations will be evaluated. The wind tunnel experiments will guide and complement field trials in South Australian and Queensland vineyards, which will optimise spray application using LiDAR and sensor sprayers on a range of grape canopies of different heights. Various spraying systems will be evaluated utilising recapture and recycle techniques to reduce spray volumes, losses to the ground and drift as well as electrostatics and optimisation of conventional airblast and rotary fan systems.

Industry Benefit

Through this project, growers will be able to achieve good spray coverage and optimised chemical efficacy while simultaneously reducing overdosing that often occurs with small grape canopies and the under dosing of larger canopies. The project will drive innovation in the industry with DRTs that reduce buffer zones.