Weed Alert: Tropical soda apple

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Status

Tropical soda apple declarations


 

Other Information

Contacts and Further Information

If you find this weed please help to prevent its further spread by contacting your local Council Weeds Officer or the nearest Department of Primary Industries office immediately for positive identification and further assistance.

Alternatively call the NSW NSW Invasive Plants and Animals Enquiry Line on
1800 680 244 or send an email to weeds@dpi.nsw.gov.au









NSW No Space 4 Weeds

Tropical soda apple (Solanum viarum)

World Status | Spread | Identification | Control | Legislation

Tropical soda apple, is an aggressive, prickly, perennial shrub 1–2 m high. It invades open to semi-shaded areas including pastures, forests, riparian zones, roadsides, recreational areas, horticulture and cropping areas. It reduces biodiversity by displacing native plants and disrupting ecological processes. Its foliage is unpalatable to livestock, thus reducing carrying capacities. Prickles on this plant restrict grazing by native animals and livestock and thickets can create a physical barrier for animals preventing access to shade and water. The plant is a host for many diseases and pests of cultivated crops, and it contains solasodine which is poisonous to humans.

It was first identified in Australia in the upper Macleay Valley in New South Wales (NSW) in August 2010, however it is believed to have been present in this area for a number of years. Subsequent surveys found infestations at Wingham, Grafton, Bellingen, Coffs Harbour, Bonalbo, Casino, Murwillumbah and Wauchope. The smaller infestations have been eradicated and the larger infestations are subject to active control programs. In 2011 infestations were discovered in the Namoi and Border Rivers-Gwydir catchments associated with the movement of cattle from infested coastal areas. Infestations were traced to properties near Tamworth, Attunga and Inverell and are currently the focus of an eradication campaign.

Tropical soda apple has the potential to spread in coastal regions of NSW and Queensland, and inland through cattle movements.

World Status

Tropical soda apple is a native of north eastern Argentina, south eastern Brazil, Paraguay and Uruguay. It was first recorded in Florida in 1987 and was known to infest 10 000 ha by 1990 and half a million hectares by 1995. By 2007 it had spread to nine other south eastern states in the USA, where it is now a Federal Noxious Weed. Tropical soda apple has also naturalised in Africa, India, Nepal, West Indies, Honduras and Mexico and outside its native range in South America.

Spread

Tropical soda apple reproduces via seed and can regenerate from root material. In NSW cattle movement is currently the major vector of spread and infestations have been found by tracing cattle movements from infested areas using the National Livestock Identification Scheme. Seed can also be spread by feral animals and birds that feed on the fruit; and via water and contaminated produce, soil and equipment.

It is strongly recommended that stock from affected areas be held in a quarantine area for 48 hours before being transported to other properties or to sale. Prevent stock from grazing and moving through infested areas and check cattle handling facilities, cattle camps and yards for seedlings and new infestations.

Identification

Tropical soda apple is an upright, branching, perennial shrub growing to 2 m in height. It has broad-based, straight, cream-coloured prickles to 12 mm long scattered on most plant parts.

Key identification features

  • Leaves are mostly 10–20 cm long and 6–15 cm wide. The upper and lower leaf surfaces are densely covered in short hairs; mid-veins and primary lateral-veins are cream-coloured on both sides of the leaves.
  • Flowers are white, with 5 petals 2–4 mm long. They occur in clusters of 3–6 off a short stem.
  • Mature fruit are yellow and golf ball-size (2–3 cm in diameter). When immature they are pale green with dark green veins, like immature water melons. In the USA plants produce an average of 45 000 seeds.

Control

Your local council weeds officer will assist with identification, control information, removal and eradication. Infestations can be spread by inappropriate control activities.

Individual plants can be manually removed, but care must be taken to remove all the root material, as plants will regrow from root fragments. Fruit should be collected and disposed of appropriately (deep burial or burnt). Particular care should be taken to remove plants in flood prone areas.

Legislation

Tropical soda apple is a Class 2 Regionally Prohibited Weed across NSW under the Noxious Weeds Act 1993. It must be eradicated and land must be kept free of the plant. As a notifiable weed, all outbreaks must be reported to the local council within 24 hours, and the plant is prohibited from sale in NSW.

Acknowledgments

Authors: Rod Ensbey, John Hosking, Birgitte Verbeek, Tony Cook; Prepared by: Jessica Grantley, Birgitte Verbeek, Elissa van Oosterhout.

References

Plantnet NSW Flora Online;van Driesche R et al. (2002). Biological control of invasive plants in the eastern United States, USDA Forest Service.

Last updated: June 2013.