Sicklepod

Native to America, sicklepod and other similar Senna species are vigorous, competitive woody shrubs. Sicklepod occurs in many tropical countries around the world, and invades pastures, roadsides, fence lines, creekbanks and waste areas. North Queensland has isolated sicklepod infestations.

Sicklepod is a restricted invasive plant under the Biosecurity Act 2014.

Scientific name

Senna obtusifolia, S. hirsuta, S. tora

Other names

Arsenic weed, coffee weed, java bean

Similar species

Description

  • Woody shrub 1.5-2.5m tall by 1m wide.
  • Leaves are 4cm long, 2cm wide, rounded at end, wedge-shaped at base, divided into 3 opposite pairs.
  • Flowers are yellow, 1cm wide, with 5 petals.
  • Seed pods are slender, 10-15cm long, 3-5mm wide.
  • Ripe pods burst open, shedding seeds.
  • Seeds are dark brown, shiny, flattened.

Habitat

  • Prefers drained, fertile soils.
  • Suited to cleared coastal forest country.

Distribution in Queensland

  • Dense infestations occur north of Mackay, south-west of Ingham, and on parts of Atherton Tableland.

Life cycle

  • Seed reserves of 2,000 seeds/m2 of soil have been recorded in dense stands.
  • May germinate at any time of year under favourable conditions.
  • Seed can remain viable for up to 10 years.

Impacts

Economic

  • Invades pasture, roadsides, fence lines, creekbanks, waste areas.
  • Potential to become major weed of many crops within 2-3 growing seasons.

How it is spread

  • Spread mainly by livestock.
  • Seeds also spread by water, animals, vehicles, machinery and footwear.

Control

Mechanical control

  • Slashing can reduce old plants to manageable size and/or kill fair percentage if certain conditions are met. However, under most conditions, slashing will not kill sicklepod.
  • Sharp slasher blade cuts will encourage plant to reshoot, so blunt blades must be used to shatter plant's stems. Slashing should always be done before seed set, preferably when plants are flowering.
  • Rotary hoeing or discing infested areas and immediately sowing with improved pastures can be effective, provided grasses are well managed.

Herbicide control

  • Using power spray or knapsack, thoroughly wet all leaves and stems to point of run-off with 1 of the spray mixtures.
  • Currently no chemical is registered.
  • Non-crop areas Not difficult to control in seedling stage; however, control rapidly becomes more difficult with increasing plant age, requiring higher herbicide application rates.
  • Crop areas Get advice from Bureau of Sugar Experiment Stations if found in your sugar crop. Herbicides used and application rates will depend on crop to be planted.

See the Sicklepod fact sheet (PDF, 962KB) for herbicide control and application rates.

Biological control

  • No known biological control agents.

Legal requirements

  • Sicklepod is a restricted invasive plant under the Biosecurity Act 2014.
  • It must not be given away, sold, or released into the environment without a permit.
  • The Act requires everyone to take all reasonable and practical steps to minimise the risks associated with invasive plants and animals under their control. This is called a general biosecurity obligation (GBO).
  • At a local level, each local government must have a biosecurity plan that covers invasive plants and animals in its area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.

More information