The plant must be eradicated from the land and the land must be kept free of the plant
Why Is It Bad?:
Is regarded as one onf the worse weeds in Australia becasue of its invasiveness, potential for spread, and economic impacts. Its main impact on pastoralism is the loss of grazing country. Rubber vine threatens waterways, woodlands and rainforests throughout northeastern Australia. It also threatens riverine vegetation, and can potentially displace the plants and animals that inhabit riverbanks, therby affecting the water quality of streams.
Rubber vine is a many stemmed shrub which can climb 30m high into tree canopies, or grow 1-3m high when unsupported in open areas. The stems are greyish brown with a smooth bark and have tow forms: a leaf bearing branched stem and a longer unbranched 'whip' with fewer leaves that extends onto nearby adjacent vegetation. the plant exudes a milky sap if scratched or broken. The leaves occur in pairs and are a glossy dark green in colour. They are oval shaped with tapered ends, 60-100mm long and 30-50mm wide.
The trumpet shaped flowers are quite large, up to 50mm long and wide, with five light purple to white petals.
The seed pods are rigid and usually occur in opposing pairs at the end of short stalks, but are quite common as single pods and occasionally triple pods. The pods are up to 120mm long and 40mm wide. the brown seeds are flat with a tuft of long, white silky hairs at one end.
Roots grow to a depth of 12m
Foliar spraying the entire plant from the ground and aerial spraying are most effective on smaller plants (less than 2 m tall, stem diameter less that 35mm). However leaves infected by the biocontrol rust will not take up herbicides. The basal bark technique, which uses spraying around the lowest bark up to a height of 500mm is effective on plants of stem diameter less than 35mm at the base. Foliar, aerial and basal bark spraying should only be conducted when rubber vine is actively growing. The cut stump method uses minimal herbicides and is effective at all times but is labour intensive and therefore best suited to scattered infestations. Soil applied residual herbicides are effective when applied before rain. It is highly recommended that advice is obtained from the relevant state/territory weed management agency prior to the use of soil applied herbicdes.
Fire is an especially valuable part of the integrated control of rubber vine because it kills surface seeds, seedlings and adult plants, yet is relatively inexpensive. If there is sufficient fuel, rubber vine can be burnt while green with good success. The timing of fire is crucial to its success as fires must be hot enough to kill mature rubber vine. It is advisable to burn after first rains as this reduces the risk of prolonged periods of bare earth and erosion.
Slashing & Cutting:
Slashing harms the plant but often does not kill it.
Two bilogical control agents have become widespread in QLD since their release in the early 1990's. The rubber vine rust Maravalia cryptostegiae forms on the underside of leaves and causes them to turn yellow and drop. The other agent is the moth Euclasta whalleyi, whose caterpillars feed on rubber vine leaves between March and October. Both agents, especially the rust, cause damage (eg reduced flowering, seed pod production and leaf cover) and occasionally the death of established plants.
Cultivation & Scalping:
Blade or disc ploughs and cutter bars provide reasonable control of rubber vine, but are most often used to penetrate very dense infestations to allow easier access or to oen up the canopy.
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Image Credit: Don Mackenzie
Image Credit: Don Mackenzie - Bourke Shire Council