For effectively controlling Leucaena leucocephala, several herbicide options are recommended, each with specific application methods and rates. The "best" choice often depends on the scale of infestation, environmental considerations, and the preferred application technique.
Effective Herbicides for Leucaena Control
Managing Leucaena requires potent herbicides that can target this resilient woody weed. The following table outlines effective herbicide combinations and their recommended application rates:
| Herbicide Combination | Commercial Product Name | Active Ingredients | Recommended Rate | Application Method/Notes |
|---|---|---|---|---|
| Metsulfuron-methyl + Aminopyralid | Di-Bak AM | Metsulfuron-methyl 75 g/kg + Aminopyralid 93.7 g/kg | 1 capsule for every 10 cm of circumference (stem injection/basal frill) | Suitable for individual tree treatment. |
| Picloram + Aminopyralid | Vigilant II ® | Picloram 44.7 g/L + Aminopyralid 4.47 g/L | Undiluted | Often used for cut stump or basal bark treatments. |
| Triclopyr + Picloram | Access™ | Triclopyr 240 g/L + Picloram 120 g/L | 1.0 L in 60 L of diesel (or biodiesel such as Biosafe) | Applied as a basal bark spray or to cut stumps. |
Detailed Application Insights
Understanding the application method is crucial for successful Leucaena control.
1. Metsulfuron-methyl + Aminopyralid (Di-Bak AM)
This combination is highly effective for individual Leucaena plants through direct stem injection or basal frill application.
- Application: For every 10 cm of the tree's circumference, one capsule of Di-Bak AM is inserted into the stem. This method delivers the herbicide directly into the plant's vascular system, ensuring systemic uptake and root kill.
2. Picloram + Aminopyralid (Vigilant II ®)
Vigilant II is a potent option, typically applied undiluted for targeted treatment.
- Application: This formulation is generally used for cut stump treatments, where the herbicide is applied immediately to the freshly cut surface of the stump to prevent regrowth. It can also be used for basal bark applications on smaller stems, where the herbicide is sprayed around the lower bark of the plant.
3. Triclopyr + Picloram (Access™)
Access™ is a robust herbicide that requires dilution with a carrier like diesel or biodiesel for optimal penetration.
- Application: It is commonly mixed at a rate of 1.0 L of Access™ in 60 L of diesel (or a biodiesel such as Biosafe). This mixture is then applied as a basal bark spray, thoroughly wetting the lower 30-50 cm of the trunk, or to cut stumps to prevent resprouting. The oil-based carrier helps the herbicide penetrate the bark and be absorbed by the plant.
For further information on Leucaena control and management strategies, refer to reputable sources such as the NSW WeedWise portal.
