Common thornapple (Datura stramonium)

Common thornapple is an annual plant with large, trumpet-shaped flowers and spiny fruit. The whole plant is poisonous to people, pets and livestock.

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How does this weed affect you?

Common thornapple is a vigorous growing plant that can:

• poison people and animals
• reduce crop yields (e.g. sorghum, cotton, soybeans)
• make harvesting produce difficult
• reduce pasture productivity
• host diseases of horticultural crops such as tomatoes and potatoes
• compete with native plants.

Human poisoning

The entire plant, particularly the seeds, is poisonous. It contains topane alkaloids, toxins that can cause serious illness or death. Children are very sensitive to common thornapple poisoning. They have been poisoned by sucking nectar from flowers and eating seeds. Eating the plant can cause:

• thirst
• dilated pupils
• high temperatures
• weak or rapid pulse
• incoherence or hallucinations
• vomiting
• breathing problems
• convulsions.

Touching the plant can cause dermatitis, nausea and headaches in some people.

 What to do if a person is poisoned:

•  If the patient is unconscious, unresponsive or having difficulty breathing dial 000 or get to the emergency section of a hospital immediately.
•  If the patient is conscious and responsive call the Poisons Information Centre on 13 11 26 or your doctor.
•  If going to a hospital take a piece of the plant for identification.

Livestock poisoning

The toxins in common thornapple can affect horses, cattle, sheep, pigs, dogs and poultry. Livestock usually avoid eating it. Most cases of livestock poisoning are caused by the weed being present in hay, silage or contaminated grain. Symptoms in animals include:

• weak or rapid pulse
• subnormal temperatures
• lack of saliva
• widely dilated pupils
• slow breathing
• convulsions
• coma.

What does it look like?

Common thornapple is a leafy annual herb up to 1.5 m tall but usually 30-60 cm tall. It grows quickly and usually flowers from summer to autumn and die in autumn.

 Leaves are:

• dark green on top, light green underneath
• 8-35 cm long and 5-20 cm wide
• oval or broadly triangular shaped with jagged edges
• soft and hairless
• alternate along stems.

The leaves smell foul when crushed.

Flowers are:

• trumpet-shaped with 5 lobes (fused petals) each tapering to a thin point about 1 cm long
• white to light purplish
• 5-10 cm long
• perfumed
• closed at night.

Fruit are:

• an egg-shaped capsule
• 5.0-6.5 cm long and 2-5 cm wide
• covered in spines of different lengths, up to 2 cm long
• held upright.

Seeds are:

• dark brown to black
• 3-4 mm long and 2-3 mm wide
• kidney-shaped and flat.

Stems are:

• green to purple
• upright and 30 cm-1.50 m long
• round
• smooth or slightly hairy.

Roots

The roots are branched and either shallow, or a taproot up to 1 m deep, with stringy side roots.

Where is it found?

Common thornapple has spread widely across most of NSW except the most Western arid areas. It was first recorded in Sydney in 1802.

It is most likely native to tropical and subtropical parts of South and Central America.

What type of environment does it grow in?

Common thornapple grows in subtropical and warm-temperate regions. It grows best in warm, open, sunny areas with well-drained, rich, moist soils but it can also tolerate dry conditions. It is often found:

• along roadsides
• in fields and pastures
• in disturbed areas including gardens and old stockyards
• along riverbanks and flats.

How does it spread?

Common thornapple spreads by seed. Each plant produces up to 30 000 seeds which can live in the soil for up to 40 years. Germination can occur throughout the year but occurs mostly in spring. Disturbing the soil encourages seeds to germinate. Seeds are spread by:

• water
• mud stuck to vehicles and machinery
• as a contaminate in hay or other seed produce.

Acknowledgements

2021 edition: Prepared by WildMatters; Technical review by Wendy Gibney; Editing by Birgitte Verrbeek. 

More information

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Control

Common thornapple can be controlled by herbicides, mulching, slashing, hand-pulling or chipping.

Preventing plants from seeding is the most effective way to control it. Control programs will need to be repeated over many years because the seed lasts for decades in the soil.

Wear personal protective clothing including gloves and long sleeves when managing this plant.

Prevention

Purchase pasture or crop seeds from a registered grower.

When buying hay, ask if a vendor declaration is available. Have designated feed out areas that can be checked regularly for weeds.

Always check and clean any machinery or vehicles that have been in an infested area before they are moved to a noninfested area.

Physical removal

Hand weeding

Seedlings and small plants can be hand pulled or dug out. Weeding will be easier in damp soil. Take care to remove as much of the root as possible otherwise plants might regrow.

Cultivation

Cultivation of large infestations works well when plants are seedlings. It is not as effective on larger plants because their roots are tougher and can stay in the soil. Cultivation may need to be repeated several times because seedlings can germinate over many months. Avoid cultivating any plants with fruit. Disturbing the soil by cultivation can cause dormant seeds to germinate, therefore follow up will be needed.

Slashing

Slashing before the weeds set seed can be useful. But slashing seeding plants will spread the seeds.

Chemical control

Spraying is most effective on actively growing seedlings or young plants.

Boom spraying is useful for large infestations.

Spot spraying is useful for isolated plants or when infestations are closed to desirable plants.

Herbicide options

See Using herbicides for more information.

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2,4-D amine 625 g/L (Various products)
Rate: 1.6 to 2.4 L per ha
Comments: Pasture
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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2,4-D amine 700 g/L (Amicide Advance 700)
Rate: 285 mL in 100 L of water
Comments: Pastures, rights of way and Industrial areas
Withholding period: Do not graze or cut for stock food for 7 days after application.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Bromacil 800 g/kg (Various products)
Rate: 3.5 or 6.5 kg per ha
Comments: Industrial areas and rights of way: lower rate for lighter soil
Withholding period: Not required when used as directed.
Herbicide group: C, Inhibitors of photosynthesis at photosystem II (PS II inhibitors)
Resistance risk: Moderate

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Glyphosate 450 g/L (Various products)
Rate: 1.6 to 2.4 L per ha
Comments: Boom spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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Glyphosate 450 g/L (Various products)
Rate: 400 to 560 mL per 100 L of water
Comments: Spot spray
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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Glyphosate 450 g/L (Various products)
Rate: 60 to 80 mL per 15 L of water
Comments: Knapsack spraying
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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Imazapyr 250 g/L (Various products)
Rate: 4 L per ha
Comments: Industrial areas
Withholding period:
Herbicide group: B, Inhibitors of acetolactate synthase (ALS 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 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.

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Reviewed 2021