Pest risk assessment for regulatory control of Bactrocera invadens (Diptera : Tephritidae) in the Musina area (Limpopo Province)

Abstract

Fruit flies (Tephritidae) can enter and establish in new territories due to the movement of fruit from one area to another through trade or tourism, which can negatively impact on fruit production and market access. An invader fruit fly species (Bactrocera invadens) has established on the African continent and has spread throughout sub-Saharan Africa. This newly described polyphagous fruit fly species is a successful invader species which continues to distribute and establish in new habitats. The introduction and establishment of B. invadens in South Africa may have serious market access consequences with regard to fruit exports due to its absence in the territories of many trading partners. The Musina area was considered as the study area as it is the first entry point from Zimbabwe. The national highway (N1) which runs through the area is a major route from several B. invadens infested countries in the Southern Africa region. A species initiated pest risk assessment was conveyed to determine the risk potential of this pest. The pest risk assessment (PRA) identified several pathways with a high risk to the Musina area, that B. invadens can follow. A detection survey was carried out to determine the status of B. invadens in the Musina area as support to the PRA. The detection survey continued over three years and by the second year B. invadens was detected for the first time in the study area. The detection survey was followed by a delimiting survey and the pest was eradicated in the area. After several months of no detection, it was however detected again in the area. Risk management options were suggested for regulatory control as an outcome of the pest risk assessment. These measures can be utilised by the National Plant Protection Organisation of South Africa for the commercial importation of host material of B. invadens, control of fruit imported by travellers, informal traders and national control in the event of pest incursions in the area. Corrective actions as well as quarantine actions should be implemented in an integrated approach in the affected areas.