EPPO Platform
on PRAs

Horizon scanning for prioritising invasive alien species with potential to threaten agriculture and biodiversity in Ghana


Kenis et al. (2022) Horizon scanning for prioritising invasive alien species with potential to threaten agriculture and biodiversity in Ghana. NeoBiota 71: 129-148. https://doi.org/10.3897/neobiota.71.72577 

Invasive alien species (IAS) continue to shape the global landscape through their effects on biological diversity and agricultural productivity. The effects are particularly pronounced in Sub-Saharan Africa, which has seen the arrival of many IAS in recent years. This has been attributed to porous borders, weak cross border biosecurity, and inadequate capacity to limit or stop invasions. Prediction and early detection of IAS, as well as mechanisms of containment and eradication, are needed in the fight against this global threat. Horizon scanning is an approach that enables gathering of information on risk and impact that can support IAS management. A study was conducted in Ghana to establish two ranked lists of potential invasive alien plant pest species that could be harmful to agriculture, forestry, and the environment, and to rank them according to their potential threat. The ultimate objective was to enable prioritization of actions including pest risk analysis, prevention, surveillance and contingency plans. Prioritisation was carried out using an adapted version of horizon scanning and consensus methods developed for ranking IAS worldwide. Following a horizon scan of invasive alien species not yet officially present in Ghana, a total of 110 arthropod and 64 pathogenic species were assessed through a simplified pest risk assessment. Sixteen species, of which 14 were arthropods and two pathogens, had not been recorded on the African continent at the time of assessment. The species recorded in Africa included 19 arthropod and 46 pathogenic species which were already recorded in the neighbouring countries of Burkina Faso, Côte d’Ivoire, and Togo. The majority of arthropod species were likely to arrive as contaminants on commodities, followed by a sizable number which were likely to arrive as stowaways, while some species were capable of long distance dispersal unaided. The main actions suggested for species that scored highly included full pest risk analyses and, for species recorded in neighbouring countries, surveys to determine their presence in Ghana were recommended.


  • Aleurothrixus floccosus
  • Aonidiella citrina
  • Aonidiella orientalis
  • Armillaria heimii
  • Babuvirus musae
  • Bemisia tabaci
  • Brevipalpus phoenicis sensu lato
  • Callosobruchus chinensis
  • Clavibacter michiganensis
  • Dialeurodes citri
  • Diaphorina citri
  • Dysmicoccus neobrevipes
  • Icerya purchasi
  • Ipomovirus brunusmanihotis
  • Liriomyza huidobrensis
  • Liriomyza sativae
  • Liriomyza trifolii
  • Machlomovirus zeae
  • Maconellicoccus hirsutus
  • Meloidogyne enterolobii
  • Meloidogyne ethiopica
  • Meloidogyne hapla
  • Moniliophthora perniciosa
  • Moniliophthora roreri
  • Orthotospovirus tomatomaculae
  • Phytophthora vignae
  • Potyvirus zeananus
  • Ralstonia solanacearum
  • Rhizoctonia solani
  • Rhynchophorus ferrugineus
  • Scirtothrips dorsalis
  • Spodoptera eridania
  • Tenuivirus zeae
  • Thrips palmi
  • Trioza erytreae
  • Unaspis citri
  • Xanthomonas oryzae pv. oryzae
  • Xanthomonas oryzae pv. oryzicola
  • Xanthomonas vasicola pv. musacearum


Type File Size
Pest Risk Analysis Download 320,00kB
Pest Risk Analysis Download 35,89kB

PRA Area

  • Ghana