Read information on scouting and the current black-grass situation in this January 2026 update.
Black-grass (Alopecurus myosuroides) is a high-risk invasive grass weed in temperate cropping systems. Overseas, it has reduced yields, disrupted rotations, and developed herbicide resistance. These impacts show why early detection matters in New Zealand.
New Zealand has had only isolated detections. Each response has relied on rapid reporting, strict movement controls, and repeated surveillance. This approach has prevented establishment. Continued awareness across the industry remains essential.
January is a key time to spot black-grass
By January, black-grass seed heads are likely to be at or above the crop canopy. Seed heads may be starting to mature. This is a critical window to find plants before they reach the point where seed can shed. Early detection at this stage reduces the chance of spread.
When scouting, look for:
• Seed heads held above the crop canopy.
• Patchy or single plants that stand out from the crop.
• Seed heads becoming firmer and more mature as the month progresses.
If you see an unfamiliar grass that could be black-grass, treat it as suspect and report it.
Surveillance results (good news)
AsureQuality has been scouting all paddocks related to the 2025 incursion and has found no black-grass. Paddocks still under surveillance from the 2021 incursion have also been scouted thoroughly by AsureQuality, with no black-grass found. This is very positive progress.
Reporting remains essential
Black-grass can appear anywhere. Finding it is not a cause for blame or shame. But rapid reporting through the correct channels is essential to protect the industry.
If you suspect black-grass, do not disturb the plant. Take a photo and report it immediately to the Biosecurity New Zealand Pest and Disease Hotline (0800 80 99 66).
Further information about black-grass can be found here or on the Environment Canterbury website here, or contact Ivan.Lawrie@far.org.nz or Ashley.Mills@far.org.nz