Studies on the host plants of Bactrocera invadens
From December 2004 to April 2006, field surveys were carried out in Kenya to identify the host plants of Bactrocera invadens (Diptera: Tephritidae – EPPO Alert List). In addition, host preference studies were carried out in the laboratory in choice and no-choice tests. Fruits belonging to 90 plant species (representing 40 plant families) were collected from the Coastal, Eastern and Rift Valley provinces of the country where large populations of fruit fly occur, and where fruit and vegetable production is predominant. B. invadens was reared from a total collection of 3,913 fruits which included 14 cultivated and wild fruit species. The majority of B. invadens-infested samples were from commercial fruits.
The following 14 species are thus considered to be hosts of B. invadens:
Annona cherimola (Annonaceae) - cherimoya
Annona muricata (Annonaceae) – soursop
Annona squamosa (Annonaceae) - sugar apple
Citrus limon (Rutaceae) - lemon
Citrus reticulata (Rutaceae) - tangerine
Citrus sinensis (Rutaceae) – sweet orange
Cordia myxa (Boraginaceae) –Assyrian plum
Lycopersicon esculentum (Solanaceae) - tomato
Mangifera indica (Anacardiaceae) - mango
Musa sp. (Musaceae) - banana
Psidium guajava (Myrtaceae) - guava
Sclerocarya birrea (Anacardiaceae)
Sorindeia madagascariensis (Anacardiaceae)
Terminalia catappa (Combretaceae)
Among cultivated plants, fruits of mango, banana and citrus (lemon, tangerine and sweet orange) were the most heavily infested species. Sclerocarya birrea and Terminalia catappa were the most infested species among ‘non-cultivated plants’ (T. catappa can be used as shade trees near houses). In laboratory studies, mango and banana were also found to be the most preferred hosts compared to the 9 other cultivated plant species tested (i.e. Annona squamosa, Carica papaya, Citrus sinensis, Cucumis sativus, Lycopersicon esculentum, Persea americana, and Psidium guavava). Although the list of host plants is not exhaustive, these results confirm that B. invadens is a polyphagous pest which threatens important crops such as mangoes and bananas in Kenya.
Sources
Rwomushana I, Ekesi S, Gordon I, Ogol CKPO (2008) Host plants and host plant preference studies for Bactrocera invadens (Diptera: Tephritidae) in Kenya, a new invasive fruit fly species in Africa. Annals of the Entomological Society of America 101(2), 331-340.