CAPTAIN Cook tree (also known as yellow oleander) is native to tropical South America and the West Indies, and has often been planted in the past in private gardens, commercial landscaping and council parks.

Captain Cook tree has become a highly invasive weed in parts of Queensland, especially along creeks and in woodlands.

Captain Cook trees and seedlings compete with native vegetation.

Its leaves and capsules poison the ground under the trees, preventing other plants growing near the Captain Cook tree.

Eradication of isolated trees and seedlings can prevent thickets developing.

If left uncontrolled, Captain Cook tree can threaten pasture production, poison water, kill native plants, and poison livestock, domestic and native animals.

Captain Cook tree is a Class 3 declared pest plant under the Queensland Land Protection (Pest and Stock Route Management) Act 2002.

It is an offence to supply or sell a Class 3 plant.

A landowner may be given a pest control notice if this pest is or could have an impact on an environmentally significant area or spread into a river system.

Management strategies

The best form of weed control is prevention. Always treat weed infestations when small.

Effective control of Captain Cook tree can be achieved through a combination of mechanical and herbicide treatments or by herbicide treatment alone.

Follow-up checks and treatments must be undertaken to ensure a successful control program.

Manual control

Small individual plants may be manually removed, taking care to remove the roots. This option is not feasible for larger specimens.

Always wear gloves when removing Captain Cook plants due to the milky sap.

Mechanical control

Isolated individuals can be grubbed out with a blade, either front- or rear- mounted to a dozer or tractor.

Dense infestations can initially be cleared with a cutterbar (if the terrain and soil type permit).

Remaining broken and exposed stems should be treated with basal bark spray as soon as possible following clearing.

In order to ensure a successful control program, regrowth must be sprayed with herbicide.

Herbicide control

Method depends on the size of the target tree and thesituation. Use of a wetting agent may increase the efficacy of herbicides. Herbicides work best when plants are actively growing.

Foliar spray

Spray the whole plant thoroughly to the point of run-off, wetting every leaf during a time when the plant is actively growing.

Foliar spraying is most effective on plants less than 2m high. Don't treat infestations during hot, dry, summer periods; when windy; or when the plant is stressed from drought or waterlogging.

A surfactant should be added to the herbicide mixture at rates specified on the herbicide label.