Chilean Needle Grass (CNG) has surged across the district this year, appearing in areas where it was previously unseen. Effective weed control focuses on exploiting a plant’s weaknesses, using all available methods. While chemical herbicides are often the go-to solution, cultural and mechanical strategies also play vital roles.
CNG, however, is an exceptional challenge. This invasive grass produces about 20,000 seeds per square meter, with a staggering 98% survival rate. Unlike its relative, Serrated Tussock, which relies on windborne seeds, CNG seeds spread through contact, attaching to animals like sheep and kangaroos, as well as farm machinery and vehicles. This makes containment difficult, especially when seeds stick to visitors’ or contractors’ equipment.
Control Strategies for CNG:
1. Slashing: While slashing removes seed heads, it requires multiple applications since seeds mature at different rates. It can also spread seeds via the equipment, worsening the problem.
2. Cultivation: This approach inadvertently spreads the plant’s seeds, which are produced not only in seed heads but also within stems and under the crown. Cultivation can trigger dormant seeds to germinate.
3. Physical Removal: Pulling and burning isolated plants may work for small infestations, but large-scale areas are unmanageable this way.
4. Exclusion: Fencing off infested areas and excluding livestock, particularly sheep, during flowering and seed drop (November to February) can help. Keeping vehicles and machinery out is equally important.
5. Strategic Grazing: Grazing infested areas heavily before seed heads form, then removing livestock, requires careful timing but can suppress the plant.
6. Burning: This method often backfires, as fire stimulates germination, leading to more seedlings.
7. Farm Hygiene: Prevent seed spread by ensuring machinery, vehicles, and livestock are clean when entering the property. Avoid contractors from CNG-infested areas during flowering seasons.
8. Competition: Replanting with aggressive species like Annual Ryegrass can outcompete CNG, deplete its seed bank, and restore productivity.
CNG has been in the district for 30 years, and while eradication may not be realistic, effective management can keep it from spreading further. Combating this weed requires a coordinated, persistent effort. Use all available strategies, contain its growth, and focus on prevention.
