NGN Overcoming herbicide resistance and staggered germination in wild oats

Description:

Wild oats pose a significant challenge to growers in Central New South Wales. They are the most prevalent weed in this region and are notorious for developing resistance to several herbicides, including Group 1 herbicides such as Clethodim and Clodinafop. Additionally, the variation in dormancy in wild oat seeds after maturity can lead to delayed germination, causing the weeds to germinate in multiple cohorts or after pre-sowing sprays. Growers at the Coonamble and Manildra NGN forums raised the issue of herbicide resistant and late germinating wild oats populations in the region. This investment will conduct demonstration trials over two years in Central NSW to demonstrate a range of management strategies including the use of residual herbicides and crop competition. The results from these trials will be extended through field days, webinars, and GRDC communications channels.

Outcome:

By May 2027, the impact of late germinating wild oat population is reduced through improved grower and adviser understanding of effective management options.

Output.

Output 1.

Title: Field trials demonstrating wild oat control.

Description:

By May 2027, field trials that demonstrate the effectiveness of residual herbicides followed by a knockdown herbicide and crop competition for control of late germinating and herbicide resistant wild oats.

Deliverables include:

- Conducting a minimum of 2 field trials in Central NSW during both the 2025 and 2026 winter cropping seasons. Each field trial site is to be chosen based on known histories of infestations of wild oats.

- Field trials will demonstrate multiple residual chemistries followed by a post-emergent knockdown spray. The treatment list is to be developed in coordination with the GRDC Investment Manager and be limited to registered products.

- Field trials will also validate the effectiveness of increased crop competition on control of wild oats.

- Trial reports of each field trial are to be uploaded to GRDC Online Farm Trials.

Output 2.

Title: Communications and Extension.

Description:

By May 2027, delivery of extension and communication activities targeted at growers and advisers to increase understanding of management strategies for late germinating and herbicide resistant wild oats.

Deliverables include:

- Conducting a webinar or similar that communicates effective options for controlling late germinating wild oat populations drawing on results from the project (Output 1).

- Written content for a Factsheet targeted at growers and advisers covering the results from Output 1. This will be formatted, published and promoted through communication platforms such as GRDC Communications and WeedSmart.

- Hosting of field days at a minimum of two trial sites per year.

- Be available to provide this knowledge for GRDC Research Updates if requested.

- Be prepared to jointly host a National Grower Network meeting at field day events if requested.