Oriental Fruit fly distribution within Kandara sub county, Murang’a, Kenya

Abstract

The Oriental fruit fly (Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), previously recognized as Bactrocera invadens, presence in Kenya dates since 2003, the first record of this pest in Africa. Its phytosanitary importance resulted to avocado export ban to South Africa in 2008 and later to Seychelles, to prevent possible entry of this pest into these markets through fruit trade. To regain these markets and avoid more external market loss, this study was carried out to facilitate creation of a pest free area for fruit flies as required by the International Standards for Phytosanitary Measures (ISPM) number 26. Detection survey for the pest was conducted using 110 methyl eugenol lure-based traps laced with malathion insecticide, placed throughout Kandara Sub-County, at a density of 5 traps/km² in June 2013. The sub county has the highest concentration of small-scale farmers of avocados for export markets in Kenya. The traps were examined after 2 weeks of placement. Data on host plants was also collected. The results showed that traps captured the pest in all agroecological zones (Lower highland (LH)1, Upper midland (UM) 1, Upper midland (UM) 2 and Upper midland (UM) 3). Possible host plants observed in the farms included avocado, mango, pawpaw, guava, coffee, passion fruit, loquats, banana, citrus, and tree tomato. The pest density was highest in UM 3, which has the lowest elevation and the highest concentration of mango orchards. High trap catches recorded in market centres was associated with poor disposal of fruits. The lowest pest density was recorded at LH 1, which has the highest elevation in the sub-county. Therefore, creation of a pest free area in the Sub County will rely on effective mass trapping exercise for more than six months in order to remove all the flies, followed by protection of the area from emerging flies using strategically placed traps and various cultural practices, accompanied by strong farmer participation and stakeholder partnership to ensure integrity of exported fruit sources.