Cryptostegia Grandiflora: How to Get Rid of Rubber Vine

Native to Madagascar,Cryptostegia Grandiflora (Rubber Vine) is a fast-growing climbing plant that usually has pink-purple flowers (sometimes white to pink or pale purple). Cryptostegia Grandiflora (Rubber Vine) has shiny dark green leaves, 2-4 inches long, and triangular seed pods that grow biwinglike in 3-4 inches. The silky hairs on the seeds allow them to be transported by wind and water. Rubber vines grow on top of other plants and trees, reaching up to 50 feet, choking other vegetation. It can also wrap tightly around other plants and restrict their growth.
Rubber vine is also highly toxic: it contains cardiac glycosides, which interfere with the workings of the heart in humans and animals when the plant is ingested. When the vines dry, they develop a powdery dust that can cause violent coughing, nose swelling, and blistering eyelids. Contact with the plant's milky SAP can cause scorching rashes and blisters.
Cryptostegia Grandiflora (Rubber Vine) is a perennial woody climber or vine. Stems slender, twining or supporting plants. Under favorable conditions, old vines can climb 20-30m into the upper canopy with grayish-brown bark. Roots stout, reddish brown, penetrable to 12 m. Leaves glossy, dark green, glabrous, pale green below, separated in pairs, up to 10 cm long and 2-3 cm wide. The flowers are large and showy, white inside and pink-white to mauve outside; Corolla funnel-shaped or trumpet-shaped, 5-6 cm long and 5-8 cm in diameter.

Cryptostegia Grandiflora (Rubber Vine) Appearance

The rubber vine is a woody climbing plant. Its rampant growth has allowed it to climb trees as high as 15 metres. In the open, it forms loose multi-stemmed shrubs one to two meters high.
Leaves: It has fleshy, glossy, dark green leaves six to ten centimeters long and five centimeters wide. They are arranged in pairs opposite each other on long, smooth fleshy stems. When the stem breaks, it releases milky juice.
Flowers: Large and showy white to mauve flowers with broad funnel-shaped tubes and five spreading lobes. The tubular part is sometimes reddish. Flowers about 3.5-5 cm wide.
Seeds: They form large pods about 15 cm long. Pods usually come in pairs, joined at the base to form an angled winglike shape on a short stem. The pods distinguish it from similar native plants. Each pod contains many seeds, each of which has a long tuft of white silk.

Where is Cryptostegia Grandiflora (Rubber Vine) found?

Rubber vine has been found at several properties in north west NSW. Plants were found growing around homesteads and sheds, and are under an eradication program.
Rubber vine is native to southwestern Madagascar. It now grows throughout East Africa, Southeast Asia, the United States and Central and Southern America.
It was planted in the 1860s in northern Queensland mining town gardens. By 1917 there were reports of infestations. During the Second World War it was cultivated as a potential source of rubber.  It has spread through many parts of Queensland including the south of Cape York, Gulf of Carpentaria, along the coast south to Bundaberg and as far west as the Northern Territory border.

How does Cryptostegia Grandiflora (Rubber Vine) spread?

A hectare of rubber vine can produce millions of seeds each year. The fresh seeds have high viability (95%) and most can remain viable for 6 to 8 months. If conditions are too dry, most seeds will die after one year. Seeds can remain viable for more than a month within the seed pod, even when the pods are floating in saltwater.
 Seeds are spread short distances by wind and longer distances by water. Seed pods float, helping spread seed along waterways. Seeds can also spread attached to animal fur and in soil or mud stuck to machinery.

Cryptostegia Grandiflora (Rubber Vine) Toxicity

Human poisoning

The plant's SAP can irritate the skin and cause burning pain, rashes and blisters. Dust from dry plants can irritate the throat, nose and eyes. All parts of the plant are poisonous if eaten.
What to do if a person is poisoned:
If the patient is unresponsive, unresponsive, or has difficulty breathing, call 000 or go immediately to the hospital's emergency room. If the patient is conscious and responsive, call the Poison Information Center on 13 11 26 or your doctor.
If you go to the hospital and get a piece of the plant for identification.

Livestock poisoning

All parts of the rubber vine plant are toxic to livestock, including cattle, sheep, goats and horses. Grazing animals rarely eat much rubber vine unless other feeds are scarce. In areas where dried rubber vine leaves fell to the ground, animals died from eating feed.
Rubber vine contains cardioside. These compounds affect the heart, brain and gut. Cows that eat a small amount of rubber cane may die of heart failure after strenuous exercise, such as congres. The most common symptom is diarrhea, usually accompanied by blood.

Cryptostegia Grandiflora (Rubber Vine) Control

Physical control

• Fire

Infestations can be controlled by burning. For best results, fuel loads must be prepared and managed before burning, and sites must receive follow-up treatment after burning.
Two successive annual burns are recommended. First fire will open up infestation to increase grass growth (fuel load) while killing rubber vine plants. Second fire will clean up regrowth that follows first fire.

Mechanical control

Scattered, or medium-density infestations
Repeated slashing close to ground level is recommended.
Dense infestations
During winter, stickraking or blade ploughing reduces bulk of infestation. Pasture should be sown and windrows burned to kill residual seed. Follow-up treatment is essential.

Herbicide control

• Aerial application

Three herbicides are currently registered for aerial application. Two are foliar herbicides and one is soil-applied herbicide. Conditions that apply to foliar and soil applications of these herbicides also apply to aerial application.
Call 13 25 23 for current advice on use of this technique.

• Foliar spray

Little to no rust must be present as it affects plant health and ability to take up chemical through leaves.
Plants must be actively growing, not water-stressed, yellowing or bearing pods.
Wetting agent should be used with foliar herbicides.
Thoroughly spray bushes to point of run-off, wetting every leaf.
Avoid spraying when hot and dry (e.g. over 35°C), or when windy, specially with Agricrop Rubber Vine Spray.
Foliar spraying is most effective on plants less than 2m high. Large plants with stem diameter over  8cm may not be killed.

• Basal bark treatment

Thoroughly spray around base of plant to height of 20−100cm above ground level, spraying higher on larger plants.
Results are optimal when plant is actively growing.

• Cut stump treatment

Cut stem off as close to ground as possible (within 15cm); for smaller plants use machete or similar; larger plants may require chainsaw.
Make sure cut is horizontal.
Immediately spray or swab cut surface.
Brushcutter is cost-effective method for scattered to medium-density infestations.

• Soil application

Do not use residual herbicides within a distance of 2-3 times the height of desirable trees.
Do not use Graslan along waterways or land with greater than 20° slope.
Minimum of 50-80mm of rainfall is required before residual herbicides are taken up by plant.
See the Rubber vine fact sheet (PDF, 2.9MB) for herbicide control and application rates.

Biological control

Two biological control agents are established. Their impact depends on abundance. Both agents cause abnormal defoliation, creating an 'energy sink' that appears to reduce seed production. These agents usually do not kill established plants.

• Disease

Rubber vine rust (Maravalia cryptostegiae) is widely established and spread mainly by wind. Yellow spores form under leaves.
Rust is most active over summer, abundance being directly related to leaf wetness, which depends on rainfall and dew. Over summer, generation is completed every 7 days. Rust activity reduces over dry season.
Continued heavy infection causes defoliation, appears to reduce seed production, can kill small seedlings and causes dieback of stems. Established plants are not killed.
Defoliation promotes increased grass growth among rubber vine, increasing fuel loads required for fire management.

• Insect

Moth Euclasta whalleyi, whose larvae are leaf feeders, is also established. Observation indicates moth prefers plants stressed by either limited soil moisture or high levels of rust infection.
Moth's period of activity is dry season. Native fly parasite and disease can reduce larvae abundance.
Larvae are tapered at both ends, grow up to 30mm long, and are grey-brown with orange dots along sides. Fine silken threads and black, bead-like droppings are often found near larval feeding damage.
Creamy-brown moths are active at night and rest at 45˚ angle from a surface, with wings folded. Life cycle from egg to adult takes 21–28 days.
Defoliation reduces smothering effect on other vegetation, causes increase in leaf litter, and promotes increased grass growth among rubber vine, increasing fuel loads required for fire management. Decreased flower and pod production should reduce vine's ability to spread.