Psidium cattleianum (Strawberry Guava)

Scientific name

Psidium cattleianum Afzel. ex Sabine

Synonyms

Psidium cattleianum var. littorale (O. Berg) Fosb., Psidium littoraleRaddi

Common names

Strawberry guava, cattley guava, cherry guava, Chinese guava

Family

Myrtaceae

Origin

Native to South America (eastern Brazil and north-eastern Uruguay).

Naturalised distribution (global)

Locations within which Psidium cattleianum is naturalised include Australia, tropical and southern Africa, New Zealand, south-eastern USA and many oceanic islands with warm climates.

Introduced, naturalised or invasive in East Africa

Psidium cattleianum is invasive in parts of Tanzania (Tropical Biology Association 2010). The editors are not aware of records of the presence of  P. cattleianum in Kenya and Uganda, though this does not necessarily mean that it is absent from these countries.

Habitat

Agricultural areas, coastland, natural forests, planted forests, range/grasslands, riparian zones (banks of watercourses), ruderal/disturbed, scrub/shrublands, urban areas, wetlands (Henderson 2001). The yellow form tends to be a bit less hardy and therefore is found at slightly lower elevations. The Psidium cattleianum is now a weed in many parts of the tropics where it has quickly adapted to a variety of climates (Henderson 2001). In tropical climates, P. cattleianum is most often found growing at higher elevations, where the mean temperature is relatively cool.

Description

Psidium cattleianum is a small erect evergreen bush or tree growing to 7.5 m, although often much smaller. Its bark is grey to reddish-brown and peels readily. The leaves are dark green, opposite, elliptic to oblong and up to 8 cm long. They are shiny and leathery in texture.

Its white flowers (15-25 mm across) have five petals and numerous stamens. These flowers are borne singly in the leaf upper forks. Its fleshy fruit (2-3 cm across) turn purplish-red in colour when mature and are crowned with the some of the old flower parts. Some varieties have a yellow skin. The whitish flesh is very juicy and has a strawberry flavour which in some varieties can have a spicy taste.

Reproduction and dispersal

Psidium cattleianum produces a lot of fruit with each seed containing up to though usually less than 70 seeds. The seeds of which are dispersed by birds and mammals. It can also reshoot from stumps and produce suckers from near the base of the trunk.

Similar species

Psidium cattleianum may be confused with Psidium guajava (guava) and Psidium guineense (Brazilian guava). These species can be distinguished by the following differences:

  • P. cattleianum has hairless (glabrous) younger stems that are rounded in cross-section (cylindrical) and relatively small purplish-red or yellow fruit (2-4 cm long). Its flowers are borne singly in the leaf forks (axils) and its hairless (glabrous) glossy green leaves have 6 or 7 pairs of side veins (lateral veins).
  • P. guajava has hairy (pubescent) younger stems that are four-angled in cross-section (quadrangular) and relatively large yellow fruit (2.5-10 cm long). Its flowers are usually borne singly (occasionally in threes) in the leaf forks (axils) and its somewhat hairy (pubescent) dull green leaves have 10-20 pairs of prominent side veins (lateral veins).
  • P. guineense has hairy (pubescent) younger stems that are almost rounded in cross-section (sub-cylindrical) and relatively small yellow fruit (1-2.5 cm long). Its flowers are usually borne in threes (occasionally singly) in the leaf forks (axils) and its hairy (pubescent) dull green leaves have 6-10 pairs of side veins (lateral veins).

Economic and other uses

The fruit of Psidium cattleianum is edible and can be eaten raw or processed into jams and other products. The wood is useful for poles. However, these uses cannot compensate for this plant's overall negative impacts.

Environmental and other impacts

Psidium cattleianum can form dense thickets that exclude native vegetation and reduce native species regeneration. It is considered to be the worst invasive plant species in several islands in the Indian Ocean.

It has been nominated as among 100 of the "World's Worst" invaders by the IUCN Invasive Species Specialist Group and it has been listed as an invader in South Africa 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).

Management

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. Some components of an integrated management approach are introduced below.

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.

Small plants can be removed by hand. Larger plants can be uprooted but it is labour intensive and the plant can resprout if root fragments are left in the ground. Various chemicals can be used to control Psidium cattleianum through basal bark (painting herbicide onto the bark) and cut stump applications. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.

Research into biological control agents for P. cattleianum is being carried out in Hawaii.

Legislation

Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.

References

GISD (2010). Global Invasive Species Database online data sheet. Psidium cattleianum (tree, shrub). www.issg.org/database. Accessed March 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.

Tropical Biology Association (2010). Usambara Invasive Plants - Amani Nature Reserve - www.tropical-biology.org/research/dip/species.htm.

Editors

Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.

Acknowledgments

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).

Contact

BioNET-EAFRINET Regional Coordinator: eafrinet@africaonline.co.ke