Objective measures for powdery mildew

Summary

Objectives

To determine if improved assessment of powdery mildew contamination in field and at the weighbridge can be achieved with training and a smart phone app and with rapid spectral methods.

Background

Powdery mildew occurs in all viticultural regions of Australia and can cause significant yield and quality loss. It causes off-flavours and aromas in wines, is a negative quality marker for wine grapes and is often included in payment systems. Assessment of powdery mildew infection levels in-field and at the weighbridge is often difficult, particularly for red varieties.

Research approach

Visual assessment of the level of infection with powdery mildew will be improved by developing and refining pictorial keys for in-field use and developing a smart-phone app to support these assessments and capture the data. Strong industry involvement in this process is anticipated. The second part of the project will build on previous work demonstrating that spectral methods can quantify powdery mildew contamination in grapes. The team will focus on mid infrared spectral assessment: this part of the spectrum is more likely to correlate closely with contamination levels than that part of the spectrum used previously and would be more easily transferred to handheld robust instruments for in-field and at weighbridge use.

Industry benefit

The guides and the smart-phone app developed in this project will assist grapegrowers and winemakers to objectively assess the extent of powdery mildew infection, an important grape quality attribute.

The knowledge generated on spectral assessment will allow the development of robust methods for in-field and at weighbridge use.