Witch weeds | Primary industries & fisheries | Queensland Government

Witch weeds

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Witch weeds

Pest alert

If you have seen this plant

Call us  13 25 23

Photograph of witch weed with purple flowers
Witch weeds flowers
(Photo courtesy of Dr Rebecca Nelson)

General information

Witch weeds (Striga spp. other than native species) are a Class 1 declared pest plant in Queensland. Class 1 pests established in Queensland are subject to eradication from the state. Landowners must take reasonable steps to keep land free of Class 1 pests. It is a serious offence to introduce, keep or supply a Class 1 pest without a permit issued by Biosecurity Queensland. Penalties of up to $80,000 apply.

Witch weeds are native to tropical Africa and Asia. They include a range of different species within the Striga genus. All species of witch weed are small, parasitic herbs. Several species of witch weed rank as some of the world's worst weeds of agriculture. 

Overview

Scientific name

Striga spp. other than native species
Impacts
  • heavy infestations can reduce grain crop yields by up to 70%
  • can cause export grain to be rejected
  • effects maize, millet, legume crops, rice, sugarcane and sorghum 
  • has the potential to become serious pests if introduced or cultivated as ornamentals
  • the US has spent more than $123 million trying to eradicate witch weed from a single state
Description
  • grows to about 30 cm 
  • leaves are between 6-40 mm long and 4 mm wide and have a tapered pointed tip
  • flowers are 5-8 mm long
  • flowers vary from red, pink, white, yellow, orange or purple
  • has five-sided capsule fruit 4 mm long and 2 mm wide
Habitat and distribution
  • grows on roots of other plants
  • not known to exist in Queensland 
  • affects 35 countries
Control

  • control is difficult in agriculture
Declaration details
  • a declared Class 1 species under the Land Protection (Pest and Stock Route Management) Act 2002
  • importation, possession and sale is prohibited
  • landowners are required by law to keep their land free of this plant
Further information
  • local government office or Biosecurity Queensland, phone 13 25 23

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Page maintained by Sonia Jordan
Last reviewed 14 September 2011

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