Herbicide resistance remains a challenge for onion growers across Australia, find out how the Onions Communications & Extension project is supporting growers to combat this issue.

Input and feedback from regional grower groups is essential for the Onions Communications and Extension project and enables growers and industry to have input into how their levies are invested. As part of the needs analysis completed earlier this year, herbicide resistance (particularly in nut grass, ryegrass, and oxalis) was identified as one of the biggest issues for Australian onion producers.

A Tasmanian onion grower group met at Forthside vegetable research station in November, with Ian Layden, Queensland Department of Agriculture and Fisheries giving a presentation on weeding machinery options for Australian onion growers including autonomous, spot spraying, laser weeding and mechanical machines.

Weeding machinery offers new and exciting ways to manage weeds which is especially important in onion crops due to their poor competing ability and herbicide sensitivity. Growers discussed the options and concerns and were able to get a great overview of the different options available.

In the afternoon, growers and agronomists attended a ‘Pub in the Paddock’ event. The event was held in an onion paddock in Boat Harbour with known ryegrass resistance issues.

We had a great turnout and an interesting and informative discussion on the complexity of managing herbicide resistant ryegrass, particularly in onions.

Peter Boutsalis from Plant Science Consulting gave some great insight and local agronomists Sam Snare and Rob Jones added an important local perspective. This event really highlighted that managing resistance must be multi-pronged and farm specific. It also showed how quickly ryegrass can become a serious issue, especially given one plant can produce tens of thousands of seeds. The importance of strategic rotations in resistance management was also emphasised.

Plant pathologist researcher, Lindsey duToit speaks with growers at the Onion Lunch, Murray Bridge, November 2023

Our last 2023 onions event was on the 27 November in Murray Bridge, SA. Presenting on the day was renowned US researcher Lindsey du Toit to discuss her project ‘Stop the Rot’ and how her research and experience in American and South African onion production systems can be applied to the South Australian onion industry.

Lindsey has 23 years of experience in plant pathology and is a professor at Washington State University, and most recently being appointed chair of WSU’s Department of Plant Pathology. Dr Sam Kleemann from Plant Science Consulting also presented herbicide pot trials displaying the efficacy of herbicides on South Australian ryegrass and the importance of managing weeds in non-onion crops.

For more information on the Onion C&E project contact: science@ausveg.com.au

Listen to Grace’s report on the Onion Lunch on the Vegalogue podcast

This project is a strategic levy investment in the Hort Innovation Onion Fund, Project VN21000