Kochia (Bassia scoparia)

Kochia is a shrub that changes colour from green to yellow, red then brown as it ages. It competes with pasture grasses and crops and is toxic to livestock.

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How does this weed affect you?

Kochia spreads rapidly and:

• produces chemicals from its roots that inhibit the growth of nearby plants
• competes with pastures reducing productivity
• contaminates and reduces crop production (including cereal crops)
• hosts crop diseases 
• can cause allergies
• alters fire regimes by increasing fuel load.

Human health

Kochia pollen can cause hay fever allergies.

Livestock poisoning

Kochia is palatable to livestock but can be toxic in large quantities. Deaths have occurred in cattle, sheep and horses. The shoots contain chemicals - oxalates, nitrates and alkaloids - that can poison animals. Poisoning symptoms can include:

• dehydration
• weight loss
• weak muscles
• runny eyes
• sensitivity to sunlight.

What does it look like?

Kochia is an annual shrub that grows up to 1.5 m tall and wide. It usually has a main stem with many branches that curl upwards. The plant changes colour as it ages.

Leaves are:

• green then change to yellow, red and then brown as the plant ages
• up to 60 mm long and 8 mm wide
• veined on the underside with 3 (sometimes 5) veins running lengthwise 
• often hairy on the edges
• on short stalks at the base of the plant and stalkless up higher
• alternate along the stem.

Flowers are:

• the same colour as the leaves - green then change to yellow, red or pink then brown
• single or in pairs
• on hairy spikes 5–10 mm long
• on the upper parts of the branches where the leaf and stem join
• difficult to see.

Fruit are:

• 2 mm in diameter
• star-shaped and contain a single seed. 

Seeds are:

• dull brown
• 1.5 mm wide.

Stems are:

• hairy when young
• striped
• change colours as they age from green to yellow, red and then brown.

Similar plants:

The ornamental subspecies Bassia scoparia subspecies trichophylla (commonly known as summer cypress or burning bush) can still be found in older gardens. It has an oval rather than rounded shape, the leaves are only 1 mm wide and it does not have long hairs around the flowers.

Where is it found?

Kochia is not present in New South Wales. 

This weed was brought to Western Australia in 1990 as a fodder plant for salt-affected land. When it was recognised as weedy it was eradicated. It appeared in Tasmania as a contaminant of carrot seed in 1995, 1997 and 1998. All infestations have been eradicated and previously infested areas are checked annually.

Kochia is native to eastern Europe and western Asia. It has naturalised throughout Europe and parts of temperate Asia. It is a weed in Argentina, Canada and the United States.

What type of environment does it grow in?

Kochia grows in a wide range of soil types including those with high levels of salt. It is drought tolerant and can survive regions with less than 150 mm of annual rainfall. It thrives in areas with hot sunny summers. 

Kochia invades disturbed sites including:

• roadsides
• railways 
• eroded banks
• crops
• pastures and rangelands.

Maps and records

• Recorded presence of Kochia during property inspections (Map: Biosecurity Information System - Weeds, 2017-2023)
  These records are made by authorised officers during property inspections under the Biosecurity Act 2015. Officers record the presence of priority weeds in their council area and provide this to the NSW Department of Primary Industries. Records reflect the presence of the weed on the date of inspection.
  
  

How does it spread?

By seed

Each plant produces around 14,000 seeds in late summer. Seeds are dispersed in autumn when the plant becomes a ‘tumbleweed’. Dead plants break off at ground level and the wind blows them around. The tumbleweed can spread seeds up to 3 km. 

Kochia seeds are usually only viable for up to one year but some can remain viable for up to 4 years.  Most seeds germinate as soon as conditions allow, usually in spring. 

References

Business Queensland (2016). Queensland Government. Kochia. https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/land-management/health-pests-weeds-diseases/weeds-diseases/invasive-plants/prohibited/kochia Retrieved 19/6/2020.

CRC for Australian Weed Management (2002). Weed Management Guide: Kochia (Bassia scoparia). https://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/alert/pubs/b-scoparia.pdf Retrieved 19/6/2020.

Department of Primary Industries and Regional Development (2019). Agriculture and Food. Kochia: declared pest. https://www.agric.wa.gov.au/declared-plants/kochia-declared-pest Retrieved 19/6/2020.

Dodd, J., & Randall, R. P. (2002). Eradication of kochia (Bassia scoparia (L.) AJ Scott, Chenopodiaceae) in Western Australia. In Proceedings of the 13th Australian Weeds Conference (pp. 300-303). Perth, Australia: Plant Protection Society of Western Australia.

Friesen, L. F., Beckie, H. J., Warwick, S. I., & Van Acker, R. C. (2009). The biology of Canadian weeds. 138. Kochia scoparia (L.) Schrad. Canadian Journal of Plant Science, 89(1), 141-167.

More information

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Control

Please do not attempt to treat or dispose of this weed yourself. Report this plant if you see it anywhere in NSW by calling the helpline listed at the top of this page immediately.

NSW DPI will lead an initial response for the treatment and disposal of the plant to stop it from spreading.

Herbicide options

See Using herbicides for more information.

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PERMIT 9907 Expires 31/03/2025
Fluroxypyr 200 g/L (Comet® 200 herbicide)
Rate: 500 mL to 1 L per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock feed for 7 days after application. See label for further information.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2025
Fluroxypyr 333 g/L (Starane™ Advanced)
Rate: 300 to 600 mL per 100 L water
Comments: Spot spray
Withholding period: Do not graze failed crops and treated pastures or cut for stock food for 7 days after application. See label for more information.
Herbicide group: 4 (previously group I), Disruptors of plant cell growth (Auxin mimics)
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: One part product to 50 parts water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2025
Glyphosate 360 g/L (Various products)
Rate: One part product to 9 parts water
Comments: Splatter gun
Withholding period: Nil.
Herbicide group: 9 (previously group M), Inhibition of 5-enolpyruvyl shikimate-3 phosphate synthase (EPSP inhibition)
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2025
Metsulfuron-methyl 600 g/kg (Various products)
Rate: 10 - 20 g per 100 L water plus surfactant
Comments: Spot spray
Withholding period: Nil (recommended not to graze for 7 days before treatment and for 7 days after treatment to allow adequate chemical uptake in target weeds).
Herbicide group: 2 (previously group B), Inhibition of acetolactate and/or acetohydroxyacid synthase (ALS, AHAS inhibitors)
Resistance risk: High

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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area	Duty
All of NSW	General Biosecurity Duty All pest plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
All of NSW	Prohibited Matter A person who deals with prohibited matter or a carrier of prohibited matter is guilty of an offence. A person who becomes aware of or suspects the presence of prohibited matter must immediately notify the Department of Primary Industries Excluding the subspecies trichophylla

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Reviewed 2020