Persistence pays in battle against fleabane and silver leaf nightshade

Timing, environmental conditions and chemical choice are key to fighting fleabane and silver leaf nightshade, are the results from a Riverina weed resistance project.

The project was a collaboration between Riverina Winegrapes Marketing Board, NSW Department of Primary Industries, Nutrien Ag Solutions and Yenda Producers Co-Operative Society Ltd. 

Trials were conducted in several vineyards in the region across 2020-21 targeting fleabane (Conyza bonariensis) and silver leaf nightshade (Solanum elaeagnifolium). Key findings included:

• Pre-emergence herbicides applied in early spring will dramatically reduce weed pressure throughout the season
• Timing is key to limit seed set; weeds should be sprayed when they are young
• The double-knock spray approach was effective for controlling both fleabane and silverleaf nightshade.

“Herbicide resistance testing showed almost 40% of fleabane samples were resistant to glyphosate,” said Dr Katie Dunne, Development Officer Viticulture for the NSW Department of Primary Industries.

^{Silver leaf nightshade (Image: AdobeStock)}

Sampling was coordinated by Iva Quarisa from the Irrigation Research and Extension Committee. Trials on both weed species are ongoing. 

AgTech adoption

Data collected from Riverina’s AgTech project has highlighted the importance of the relationship between irrigation practices and yield. 

In partnership with the NSW DPI’s Climate-Smart Pilot program, different types of AgTech have been installed on a demonstration site at the Griffith Research Station, as well as on several growers’ properties across the region. 

The AgTech is designed to focus on irrigation scheduling to maximise irrigation efficiency and target yield and fruit quality. 

Plans are underway for workshops and field days in 2022 focusing on AgTech and irrigation practices.

Data collection of water usage continues for eight blocks across the region. Additional blocks were added with equipment being installed at growers’ properties. 

Vine health

Vineyard sampling continues to reveal symptoms of grapevine trunk disease. Numerous pathogens have been identified, including Botryosphaeria spp. and the Petri/esca disease complex.

Dr Mark Sosnowski and Dr Regina Billones Baaijens gave an update on their latest research findings at a workshop that was held before the pruning season. 

Disease resistant vineyard

2022 will be the first harvest for the CSIRO red disease-resistant varieties – and plans are underway to plant more of the better performing varieties. 

Wine will be made again for the 2022 vintage for the white varieties. 

“Interest in these varieties continue to grow and as the vines mature, we will continue collecting data focusing on yield and fruit quality parameters,” said Dr Dunne.