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   Psidium cattleianum (tree, shrub)  français     
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      Psidium cattleianum tree (Photo: Forest and Kim Starr) - Click for full size   Psidium cattleianum fruits (Photo: Forest and Kim Starr) - Click for full size   Psidium cattleianum flowers (Photo: Forest & Kim Starr) - Click for full size   Strawberry Guava (Photo: Wendy Strahm) - Click for full size   Psidium cattleianum bark (Photo: Amy Ferriter, State of Idaho, Bugwood.org) - Click for full size   Psidium cattleianum fruits (Photo: Amy Ferriter, State of Idaho, Bugwood.org) - Click for full size
    Taxonomic name: Psidium cattleianum Sabine
    Synonyms: Psidium cattleianum var. littorale (O. Berg) Fosb., Psidium littorale Raddi
    Common names: cattley guava (English), cherry guava (English), Chinese guava (English), Erdbeer-Guave (German), gargoulette (French-Reunion (La Réunion)), gouyavier (French-Reunion (La Réunion)), goyave de Chine (French), kuahpa (Pohnpei), ngguava (Fiji), purple strawberry guava (English), strawberry guava (English), tuava tinito (French Polynesia), waiawi (Hawai'i)
    Organism type: tree, shrub
    Psidium cattleianum is native to Brazil, but has been naturalised in Florida, Hawai'i, tropical Polynesia, Norfolk Island and Mauritius for its edible fruit. It forms thickets and shades out native vegetation in tropical forests and woodlands. It has had a devastating effect on native habitats in Mauritius and is considered the worst plant pest in Hawai'i, where it has invaded a variety of natural areas. It benefits from feral pigs (Sus scrofa) which, by feeding on its fruit, serve as a dispersal agent for its seeds. In turn, the guava provides favourable conditions for feral pigs, facilitating further habitat degradation.
    Description
    Evergreen shrub or small tree up to 8m tall. Mature branches are gray to reddish-brown with peeling bark and young branches are round and pubescent. Leaves are opposite, simple, entire, glabrous, elliptic to oblong, to 8cm (3 in) long. Flowers to 2.5cm (1.2 in) wide, born singly at leaf axils, with white petals and numerous white and yellow stamens. Fruit is a globose berry, 3-6cm (1.2-2.4 in) long, purple-red, with whitish flesh, usually sweet-tasting when ripe; seeds are numerous.
    Occurs in:
    agricultural areas, coastland, natural forests, planted forests, range/grasslands, riparian zones, ruderal/disturbed, scrub/shrublands, urban areas, wetlands
    Habitat description
    Psidium cattleianum is found on various Polynesian and Micronesian islands where it occurs as an introduced species on both disturbed land and in native ecosystems. Habitats it is found in include: sub-montane rainforest, montane cloud forest, montane rainforest, moist tropical montane forest, tropical ravine/riperian forest, tropical evergreen forest, deciduous woodland (oak), tropical montane savanna, lowland sub-tropical rainforest, scrub land, grass land, degraded forest, cultivation and agro-forestry (Mauremootoo Dr. J.).
    General impacts
    P. cattleianum is a habitat-altering weed that poses a major threat to endemic flora by competing for light and soil nutrients. Today the most serious threat to Seychelles forests is the low regeneration of native trees caused by the invasion of alien plant species such as P. cattleianum (Fleischmann, 1997, 1999, in Fleischmann et al. 2006).
    Uses
    The strawberry guava is a shrub naturalised in several subtropical areas. It produces sweet and aromatic fruit, which are appreciated by the inhabitants of La Réunion Island. Processing industries are supplied by fruit gathered from the wild. As strawberry guava thrives in humid areas where the farming potential is low, its cultivation could be a means of providing additional income to farmers, while also establishing a steady supply of fruit to industry and to markets (Normand 2002).
    Geographical range
    Native range: Native to Brazil. Introduced to Polynesia, The Mascarenes, Seychelles, Norfolk Island, and Florida.
    Known introduced range: Naturalized across peninsular Florida, with herbarium specimens documented from Seminole, Orange, Osceola, Pinellas, Hillsborough, Indian River, St. Lucie, Martin, Highlands, Glades, Hardee, and DeSoto counties.
    Introduction pathways to new locations
    Acclimatisation societies:
    Agriculture:
    Ignorant possession:
    Landscape/fauna "improvement":
    Live food trade:
    Nursery trade:
    Taken to botanical garden/zoo:


    Local dispersal methods
    Acclimatisation societies (local):
    Consumption/excretion:
    Garden escape/garden waste:
    Natural dispersal (local): Both seedlings and clonally produced suckers are commonly produced by P. cattleianum, but suckers contribute greater leaf areas. Guava's clonal growth may partially explain its success in dominating native forests (Huenneke Vitousek 1990).
    Vector (local): On Norfolk Island Psidium cattleianum seeds, fruits, flowers and leaves are fed on by birds including the rare Norfolk Island Green Parrot (Recovery Outline: Norfolk Island Green Parrot Undated). Feral pigs and non-native birds disperse Psidium seeds in Hawaii; pigs also create soil disturbances that may enhance the tree's spread (Huenneke Vitousek 1990).
    Management information
    Preventative measures: A Risk Assessment of Psidium cattleianum for Hawai‘i and other Pacific islands was prepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service. The alien plant screening system is derived from Pheloung et al. (1999) with minor modifications for use in Pacific islands (Daehler et al. 2004). The result is a score of 18 and a recommendation of: "Likely to cause significant ecological or economic harm in Hawai‘i and on other Pacific Islands as determined by a high WRA score, which is based on published sources describing species biology and behaviour in Hawai‘i and/or other parts of the world."

    Physical: Because of the huge quantities of seed that are dispersed by feral pigs, and other exotic invasive species, feral species management is a practical and necessary first step in strawberry guava management. Manual and mechanical control measures work reasonably well and are recommended where practical. Seedlings and saplings originating from seed can be uprooted. Uprooted plants may resprout or re-root in areas with greater than 2000mm of rain/year or drier areas after prolonged rain, especially if the plants are set on the ground. Manual and mechanical methods are less effective on root sprouts.

    Chemical: A number of effective chemical control measures have been developed. Strawberry guava is sensitive to picloram, dicamba, glyphosate, and triclopyr. It has been shown that undiluted picloram (Tordon 22K) is highly effective on strawberry guava as a cut stump treatment. Tordon 22K was used at Hawai‘i Volcanoes but discontinued because of unfavourable effects on non-target plants. It was replaced by Tordon RTU, which was nearly as effective, but less harmful to surrounding vegetation. Undiluted dicamba (Banvel) proved to be highly effective in a cut surface treatment. Additionally, undiluted glyphosate (Roundup) has proven to be effective using a ""hack and squirt"" method. Resource Managers in Hawai‘i found undiluted triclopyr ester (Garlon 4) to be effective as a cut-stump treatment, with 80% of plants dead and 90% of treated plants without resprouts after 21 months. A frill application of undiluted triclopyr amine (Garlon 3A) was somewhat less effective, with 11 of 20 stems dead and all trees defoliated after 21 months. Fifty percent Garlon 4 and 3A were about 50% effective. A major drawback of cut-stump treatment methods in very wet areas (>5000mm rainfall/yr) was resprouting of slash from cut stump and wood fragments from felling larger trees. Garlon is recommended because of its lack of mobility and relatively short half-life, 4-6 weeks. In addition, the research is more thorough and definitive on control methods for Garlon than other herbicides.

    Biological: Biological control is the only feasible long-term management strategy for strawberry guava. However, until recently, biological control has been perceived as unfeasible because common guava, grown commercially in Hawai‘i, is a congener of strawberry guava. Biological control is being reexamined. Several insects defoliate strawberry guava in its natural range, it is possible that insect biological control agents could be found that do not attack common guava. Memoranda of agreement has been concluded between the University of Hawai‘i and two Brazilian Universities to locate species attacking strawberry guava and not common guava. It is thought that highly specific insect pests can be found because common guava and strawberry guava are sympatric in their natural range.

    Reproduction
    Regeneration of strawberry guava is by seed and by root sprouts, which allow it to undergo expansive vegetative reproduction. Strawberry guava produces an abundance of fruits, the seeds of which are dispersed by birds and mammals.
    Strawberry guava is a prolific fruiter, with up to 70 seeds per fruit, though most fruits contain a lower number of seeds. Fruiting is more abundant for stems on the edge of the thickets.
    This species has been nominated as among 100 of the "World's Worst" invaders
    Reviewed by: Dr. John Mauremootoo (Plant Conservation Manager) & Mr. Joseph Rodriguez (Research Assistant on Alien Plant Management). Mauritian Wildlife Foundation.
    Compiled by: Dr. John Mauremootoo (Plant Conservation Manager) & Mr. Joseph Rodriguez (Research Assistant on Alien Plant Management). Mauritian Wildlife Foundation & IUCN/SSC Invasive Species Specialist Group (ISSG)
    Last Modified: Monday, 16 August 2010


ISSG Landcare Research NBII IUCN University of Auckland