Silverleaf nightshade (Solanum elaeagnifolium)

Silverleaf nightshade grows in summer. It grows in dense colonies and is very difficult to control.

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How does this weed affect you?

Silverleaf nightshade is one of the most costly weeds for grain crop producers. It can:

  • halve summer crop yields through direct competition
  • reduce winter crop yields by depleting soil moisture
  • invade pasture and reduce sub-clover growth
  • reduce annual pasture growth in autumn winter
  • poison stock if they eat ripe berries
  • be expensive to control.

Livestock poisoning

Silverleaf nightshade contains toxic alkaloids. These are most concentrated in ripe fruit. Livestock poisoning is uncommon. Symptoms of poisoning include:

  • diarrhoea
  • head held low or pressing the head against solid objects
  • weight loss
  • death after 1 – 2 weeks.

What does it look like?

Silverleaf nightshade is upright and branched. It grows up to 60 cm tall.

Leaves are:

  • 5 – 10 cm long
  • with wavy edges
  • silvery-green on top
  • pale underneath
  • sometimes with brown-yellow spines underneath.

Flowers are:

  • star-shaped when open
  • up to 25 mm in diameter
  • with five purple or white petals
  • with five yellow stamens 7 – 9 mm in length.

Berries are:

  • green striped when young
  • yellow-orange and about 1 cm in diameter when ripe
  • round and smooth.

Green berries as small as 7 mm can contain viable seeds. Plants produce up to 60 berries, each containing 10 – 210 seeds.

Stems are:

  • covered in spines that are:
    • about 5 mm long
    • brown-yellow.

Roots are:

  • deep, growing from 2 – 5 m
  • extensive and interconnecting.

Interconnected root systems help give silverleaf nightshade its competitive ability and persistence.

Similar looking species

Silverleaf nightshade looks like Quena, Western nightshade, and Brazilian nightshade.

Quena is shorter, only growing to 30 cm tall. It rarely has spines on the stems. It also has oval-shaped fruit, pale green unripe berries and shorter stamens (3.5 – 5 mm long).

Western nightshade is also shorter, only growing to 30 cm tall. It has spines on the leaves as well as stems. It’s fowers only have 4 petals and 4 stamens (3.5 – 5 mm long) and the fruit are cone-shaped with a small bump on the end.

Where is it found?

Silverleaf nightshade grows in most parts of NSW. It is native to North America. It was first found in Australia in 1901 at Bingara on the north-west slopes of NSW.

What type of environment does it grow in?

Silverleaf nightshade grows on most soil types. Seedlings grow better in disturbed soil and germinate best:

  • at depths between 1 and 3 cm
  • when soil temperature is above 15°C at 3 cm depth.

Distribution map

How does it spread?

The climate affects how silverleaf nightshade spreads. In summer rainfall areas silverleaf nightshade grows from seed and root segments. In winter rainfall areas it tends to grow more from root fragments.

By seed

Birds and livestock eat the fruit and spread the seeds. Seed can take up to 2 weeks to pass through the gut. About 10% of seed that passes through the digestive tract remains viable. Water also spreads seeds.

By plant parts

Cultivation breaks roots and machinery spreads them to new areas. Silverleaf nightshade can grow from root fragments as small as 1 cm. All parts of the root system can form shoot buds. If kept damp, root pieces can remain viable in the soil for up to 15 months.

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Control

Long-term control of silverleaf nightshade needs to consider that:

  • up to 80% of seeds are viable
  • depending on rainfall, seedlings emerge from late spring until autumn
  • flowering is from November to March
  • berries grow from December to March
  • plants are dormant in winter and produce new shoots in spring.

Controlling seedlings and seed set for 3 – 5 years reduces seed numbers in the soil.

Prevention

To reduce the risk of moving silverleaf nightshade to clean areas:

  • hold stock that have been in silverleaf nightshade areas in an easy to monitor area for two weeks before moving into clean paddocks.
  • clean machinery before moving from infested to clean areas.

Pasture Management

Healthy spring and summer pastures compete with silverleaf nightshade during its growing season. Lucerne’s deep roots dry out the soil and limit silverleaf nightshade regeneration. In summer rainfall areas, perennial pastures provide the best competition.

Do not let livestock, particularly sheep, graze fruiting plants.

Cultivation

Avoid cultivating as it moves root pieces to clean areas.

Slashing

Slashing does not control silverleaf nightshade. It recovers quickly, even in drought. Berries can grow close to the ground below the slash height.

Biological control

The are no biological control agents in Australia.

Allelopathy

Some plants release chemicals from their roots that inhibit other species. This is called allelopathy. Some Eucalyptus trees may be allelopathic to silverleaf nightshade. The most promising have been Eucalyptus brokwayi (Dundas mahogany), E. dundasii (Dundas blackbutt), E. spathulata (Swamp mallet) and E. salubris (Gimlet gum). These trees gave good control to just outside their drip lines.

Chemical Control

Spot spray small infestations. Cover all above ground parts with herbicide. Repeat sprays are necessary.

Spray:

  • immediately after winter harvest or at the end of winter pastures
  • new shoots in spring
  • in summer when berries are young.

Do not spray when plants are stressed or dormant.

Herbicide options

WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.


2,4-D 300 g/L + Picloram 75 g/L (Tordon® 75-D)
Rate: 650 mL in 100 L of water
Comments: Spot spray. Spray to wet thoroughly. Extend treated areas beyond the last plant for 1 m.
Withholding period: 1-8 weeks (see label).
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


2,4-D 300 g/L + Picloram 75 g/L (Tordon® 75-D)
Rate: 15.0 L/ha
Comments: Boom spray. Apply at early flowering before berry set.
Withholding period: 1-8 weeks (see label).
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


Fluroxypyr 333 g/L (Staraneā„¢ Advanced)
Rate: 300 mL in 100L of water
Comments: Delay applications till majority of shoots have emerged. Follow-up treatment will be required
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


Glyphosate 360 g/L (Roundup®)
Rate: 2.0 L in 100 L of water
Comments: Apply at early flowering to berry set stage, spray thoroughly to wet. Use only with good soil moisture conditions.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate


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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.
All of NSW Prohibition on dealings
Must not be imported into the State or sold
Central Tablelands
Exclusion zone: whole region except the core infestation area of Cowra Council, Cabonne Council and Mid-Western Regional Council
Regional Recommended Measure*
Exclusion zone: The plant should be eradicated from the land and the land kept free of the plant. Land managers should mitigate the risk of the plant being introduced to their land. Core infestation area: Land managers should mitigate spread from their land. Land managers reduce impacts from the plant on priority assets.
Central West Regional Recommended Measure*
Land managers should mitigate the risk of the plant being introduced to their land. The plant should not be bought, sold, grown, carried or released into the environment. Land managers to reduce impacts from the plant on priority assets.
Hunter Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
North West Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. Land managers reduce impacts from the plant on priority assets.
Northern Tablelands Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. The plant should not be bought, sold, grown, carried or released into the environment.
Western Regional Recommended Measure*
Land managers mitigate the risk of the plant spreading from their land. Land managers reduce impact of plant on priority assets (dryland farming areas).
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfill the general biosecurity duty for this weed click here

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For technical advice and assistance with identification please contact your local council weeds officer.
For further information call the NSW DPI Biosecurity Helpline on 1800 680 244 or send an email to weeds@dpi.nsw.gov.au

Reviewed 2018