Viticulture

Less guesswork

By Country News

Grapegrowers now have more tools to tackle grapevine disease and disorders, with the launch of a new app earlier this month.

Developed by University of Adelaide researchers and collaborators, with the support of Wine Australia, PMapp and Grape Assess use technology to assess problems including bunch rot, downy mildew, insect damage, sunburn and powdery mildew.

PMapp allows users to quickly assess the visual severity of powdery mildew on each bunch of grapes and determine an estimated percentage of the surface area of the bunch affected by matching it with a computer-generated image.

The app calculates the proportion of bunches affected and the surface area affected, and emails results that can be analysed via a spreadsheet, which includes a record of GPS co-ordinates and other details of the assessment.

Head researcher Eileen Scott said while PMapp had been growing in popularity since its release in the 2015-16 growing season, the feedback from vignerons was that its GPS system did not provide enough capability for some assessors. So this has been upgraded to deliver GPS accuracy to about 10m.

The Grape Assess tool, which allows the user to access the severity categories used in PMapp for powdery mildew or to set up new customised assessments, was also a response to user demand.

Through the app the user can select the part of the vine being assessed from a built-in list including leaf, berries, trunk and roots. The aim is to expand Grape Assess further to include grapevine trunk disease assessment.

■PMapp and Grape Assess are free from the Android and Apple app stores.