Any quarantined area established under this subchapter shall remain in effect until the quarantined pest described in §19.500 of this title (relating to the Quarantined Pest) is eradicated from that area. The quarantined pest shall be considered eradicated from a quarantined area when no additional Mexican fruit flies are detected for a time period equal to three consecutive generations after the most recent detection. For the Mexican fruit fly, the number of days required to complete a reproductive cycle, one generation, is temperature dependent; therefore, a day-degree model will be used to calculate the duration of each consecutive generation.