PROBABILITY OF DETECTING CARIBBEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE) INFESTATIONS BY FRUIT DISSECTION

Quarantine inspectors search for fruit fly infestations in incoming shipments by visual inspection and by dissecting or cutting a sample of fruit in each shipment. The reliability of the latter procedure for detecting fruit fly larvae is questionable and, therefore, a test was conducted to determine its effectiveness. Infested grapefruit, mangoes, guavas, and carambolas were cut open to determine the efficacy of cutting fruit in detecting larval infestations of Caribbean fruit flies, Anastrepha suspensa (Loew). From 1 to 36% of the larvae were detected by dissection, but 17.9 to 83.5% of the infested fruit were detected. The percentage of Caribbean fruit fly larvae present in an infested fruit that can be detected by cutting varies with the type of fruit infested. The overall percentage of infested fruit detected also varies in the same manner. Carambolas were the easiest fruit in which to find larvae and green guavas the most difficult. Overall, only 9.5% of the larvae in field-infested guavas and 16.9% of those in cage-infested fruits were detected. Between 17.9% (green guavas) and 83.5% (carambolas) of the infested fruit was detected. There was considerable variation in the number of larvae found by different inspectors.