Project overview

Defoliation is a critical step in preparing cotton for picking, yet in recent years growers have needed more spray passes to achieve effective leaf removal. Cooler late-season conditions, denser canopies, and variable spray environments have all contributed to declining harvest-aid performance, leading to extra costs and the risk of fibre quality penalties. 

The Spray Timing Platform project is developing a digital tool to help growers and consultants optimise when to apply harvest-aid chemicals. By combining canopy temperature, weather forecasts, inversion risk, and crop readiness indicators, the platform will provide real-time guidance on the best spray windows to maximise efficacy and reduce the need for multiple passes. 

Delivered in partnership with Goanna Ag, the platform will integrate with existing farm systems and decision-support tools (including CottonTracka), improving harvest logistics, reducing costs, and supporting higher fibre quality across Australian cotton systems. 

Outcomes and achievements

• Designed a spray timing decision platform incorporating crop, weather, and environmental data
• Integrated canopy temperature sensors and inversion/forecast data from Goanna Ag and the WAND tower network
• Developed risk flags for unsuitable spray conditions (e.g., low Delta T, inversions, rainfall)
• Modelled potential economic benefits (up to $40/ha saved by avoiding extra sprays; up to $800/ha protected through reduced leaf contamination penalties)
• Created a prototype suitable for field testing at TRL 6. 

Project status