MANIPULATING AND ENHANCING CITRUS-FRUIT RESISTANCE TO THE CARIBBEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE)

The natural resistance of citrus fruit to attack by the Caribbean fruit fly (caribfly) varies according to fruit senescence and cultivar. Lemons are virtually immune, oranges are highly resistant, and grapefruit are initially somewhat resistant, at least before becoming senescent. A method allowing an extension of the innate early-season resistance of grapefruit to fruit flies is described. Elucidation of lemon immunity factors is needed so that the responsible factors can be incorporated into less resistant cultivars, perhaps through use of genetic engineering techniques. By extending and/or increasing resistance of grapefruit, it may be possible to achieve adequate prevention of caribfly infestation throughout most of the season without the need to use expensive and troublesome postharvest disinfestation treatments in order to ship the fruit to quarantine-sensitive states and countries.