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   Psidium guajava (arbre, arbuste)  English     
Écologie Distribution Gestion Impacts Références
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         Études de cas sur la gestion
    Ascension Is.
    Futile' attempts to control Psidium guajava were made around 1900 (Ashmole and Ashmole, 2000 in Varnham, 2006).
    mechanical means have proven most successful
    Galapagos Islands
    Psidium guajava is controlled in the Galapagos, but eradication is not considered feasible at present.
    Targeted for eradication, despite this not being seen as feasible.
    Raoul Is. (Kermadec Islands)
    This species has been subject to an eradication programme on Raoul Island since 1972, and is ranked Category A(i) - known to have the potential to significantly alter the vegetation of Raoul Island. Raoul Island has been divided into 13 weeding blocks for the purpose of controlling and eradicating alien plants since 1972, which make up 64% of the vascular plant flora on Raoul Island. These are divided into active plots which are searched at least twice a year, and null plots which are searched at least once every two years. Grid searching is used to examine the areas with easier access, while steep cliffs are searched using binoculars or a telescope. This is carried out when plants such as Caesalpinia decapetala are in flower (June-November). Aerial surveillance is carried out periodically which has been useful in identifying flowering trees such as Senna septemtrionalis, mature vines of Passiflora edulis or trees of Olea europaea ssp. cuspidata. The initial knockdown phase involved for most species the cutting of mature individuals and painting of stumps with herbicides, or scattering herbicide granules around them. Blanket spraying was used to treat dense, inaccessible infestations. Subsequent searches involve the removal of any seedlings or young plants found. If a mature plant is found, the fruit is removed for burning, the stem is cut and herbicide applied. Information regarding the eradication programme is stored on an Access database. Psidium guajava can resprout vigorously from cut stumps, and may require many applications of herbicide. Less than 100 individuals have been removed since 1997, and all have been removed from Denham Bay. The importation of alien plants to Raoul Island is prohibited.
    San Cristobal Is. (Ecuador)
    45% of species introduced to the Galapagos Islands have been naturalized and of those, 32 are considered aggressive and have invaded extensive areas. The invaders affect the native vegetation negatively, changing the composition of the community and threatening populations of rare species. The majority of the introduced plants are found in the humid highlands where agriculture is the major activity and the conditions are better. The most noxious of these plants are the trees and shrubs that invade the native vegetation below the highest areas. The present methods of control are limited to removal by hand and by use of herbicides. Removal by hand requires continued effort since the plants may sprout from fragments of roots or branches. Few quantitative studies have been carried out to determine the type, concentration and method of application of herbicides. A 1999 study evaluated the effectiveness of three types of herbicide (glyphosate, picloram and triclopyr) in different concentrations to determine which method of application (“hacking and spraying”, spraying the bark and fumigation) is the most effective and the least damaging to the surrounding vegetation. These experiments were carried out on trees of Cestrum auriculatum, Cinchona pubescens, Cordia alliodora, Psidium guajava and Syzygium jambos and on the shrubs Kalanchoe pinnata, Lantana camara and Rubus niveus (Gardener et al., 1999).

    Please follow this link Rentería et al 2006 to An illustrated guide providing practical information for the effective control of the worst invasive plant species in Galapagos. Designed for farmers and other land managers, it describes manual and chemical control methods. Cedrela odorata is among 23 introduced species with descriptions and control options listed.

         Ressources pour la gestion/Liens

    1. Daehler, C.C; Denslow, J.S; Ansari, S and Huang-Chi, K., 2004. A Risk-Assessment System for Screening Out Invasive Pest Plants from Hawaii and Other Pacific Islands. Conservation Biology Volume 18 Issue 2 Page 360.
            Résumé: A study on the use of a screening system to assess proposed plant introductions to Hawaii or other Pacific Islands and to identify high-risk species used in horticulture and forestry which would greatly reduce future pest-plant problems and allow entry of most nonpests.
    2. IUCN/SSC Invasive Species Specialist Group (ISSG)., 2010. A Compilation of Information Sources for Conservation Managers.
            Résumé: This compilation of information sources can be sorted on keywords for example: Baits & Lures, Non Target Species, Eradication, Monitoring, Risk Assessment, Weeds, Herbicides etc. This compilation is at present in Excel format, this will be web-enabled as a searchable database shortly. This version of the database has been developed by the IUCN SSC ISSG as part of an Overseas Territories Environmental Programme funded project XOT603 in partnership with the Cayman Islands Government - Department of Environment. The compilation is a work under progress, the ISSG will manage, maintain and enhance the database with current and newly published information, reports, journal articles etc.
    5. Swaziland's Alien Plants Database., Undated. Psidium guajava
            Résumé: A database of Swaziland's alien plant species.

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ISSG Landcare Research NBII IUCN University of Auckland