Host Status of Avocado ('Hass') to Ceratitis capitata, Ceratitis rosa, and Ceratitis cosyra (Diptera: Tephritidae) in South Africa

摘要

Ceratitis capitata (Wiedemann), Ceratitis rosa Karsch, and Ceratitis cosyra (Walker) (Diptera: Tephritidae) are pests potentially associated with avocado (Persea americana Mill.) in South Africa. The aim of the study was to determine the host status of 'Hass' avocado to these tephritid pests over 4 yr. Unpunctured harvested avocado was exposed to fruit flies in the laboratory under no-choice conditions for 24 h. In field studies, each species was exposed for 48 h under no-choice conditions to avocado attached to the tree. Fruit was harvested immediately, 4, 8 and 18 d after exposure. In all the experiments, the fruit was incubated at 25 degrees C for 49 d after harvest. Hass avocado fruit was sourced from pack-houses throughout the avocado production areas and inspected for any internal pests. Similar inspections were done from 2005 to 2008 at arrival in Europe following standard export procedures. Analysis indicated that Hass avocado is a conditional nonhost for C. capitata and a poor but potential host for C. rosa and C. cosyra. No requirement for a risk mitigation treatment for C. capitata on South African Hass avocado was found. Fruit sampling data did not produce any infested fruit, suggesting that natural conditions and/or existing procedures functioning in a systems approach are likely to mitigate the quarantine risks of C. rosa and C. cosyra on Hass avocado in South Africa.