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paired leaves with several pairs of veins (Photo: Sheldon Navie)
flowers are usually borne in threes in the leaf forks (Photo: Sheldon Navie)
close-up of flowers with numerous stamens (Photo: Sheldon Navie)
close-up of hairy leaf undersides (Photo: Sheldon Navie)
white flowers (Photo: Sheldon Navie)
Psidium guineense Swartz (R)
P. araca Raddi; P. guyanensePers.
Brazilian guava, Guinea guava, West Indies guava, wild guava
Native to tropical America.
Locations within which Psidium guineense is naturalised include South Africa, Tanzania, India, Australia, Indonesia and French Polynesia.
Psidium guineense is invasive in parts of Tanzania (Tropical Biology Association 2010). The editors are not aware of records of the presence of P. guineense in Kenya and Uganda, though this does not necessarily mean that it is absent from these countries.
Psidium guineense is a relatively slow-growing shrub 1-3 m tall and sometimes a tree to 7 m; with greyish bark, hairy young shoots and cylindrical or slightly flattened branchlets. The evergreen, greyish leaves, 3.5-14 cm long and 2.5-8 cm wide, are stiff, oblong, elliptic, ovate (egg-shaped with broad end at base) or obovate (egg-shaped leaf with the narrower end at the base), sometimes finely toothed; scantily hairy on the upperside but coated beneath with pale or rusty hairs and distinctly dotted with glands.
Flowers, borne singly or in clusters of 3 in the leaf axils, are white and have 150 to 200 prominent stamens. The fruit, round or pear-shaped, is between 1-2.5 cm wide, with yellow skin, thick, pale-yellowish flesh surrounding the white central pulp, and of acid, resinous, slightly strawberry-like flavour. It contains numerous small, hard seeds and is quite firm even when fully ripe.
Flowers are white and borne singly or in clusters of 3 on the leaf axils. Fruit is yellow and fairly round, 1-2.5 cm in diameter. Each fruit contains many small hard seeds.
The seeds are dispersed by birds and mammals.
Psidium guineense may be confused with Psidium cattleianum (strawberry guava) and Psidium guajava (guava). These species can be distinguished by the following differences:
The wood is strong and used for tool handles, beams, planks and agricultural instruments. The bark, rich in tannin, is used for curing hides (Daehler 2005). The plant has medicinal uses. However, these uses cannot compensate for this plant's overall negative impacts.
Psidium guineense can form dense thickets that exclude native vegetation and reduce regeneration in forest edges and gaps.
P. guineense has been listed as a Category 3 invader in South Africa (no further planting is allowed - except with special permission - nor is trade in propagative material. Existing plants must be prevented from spreading).
The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species.
The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing (early detection and rapid response). Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management.
The editors could not find any specific information on the management of this species.
Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.
Daehler, C. (2005). Psidium guineense Risk Assessment Results. Pacific Island Ecosystems at Risk (PIER). www.hear.org/pier/wra/pacific/psidium_guineense_htmlwra.htm. Accessed February 2011.
Henderson, L. (2001). Alien weeds and invasive plants. A complete guide to declared weeds and invaders in South Africa. Plant Protection Research Institute Handbook No. 12, 300pp. PPR, ARC South Africa.
Pacific Island Ecosystems at Risk (PIER). Psidium guineense Sw., Myrtaceae: plant threats to Pacific ecosystems. www.hear.org/pier/species/psidium_guineense.htm. Institute of Pacific Islands Forestry, Hawaii, USA.
Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.
This fact sheet is adapted from The Environmental Weeds of Australia by Sheldon Navie and Steve Adkins, Centre for Biological Information Technology, University of Queensland. We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).
BioNET-EAFRINET Regional Coordinator: [email protected]