COMMODITY TREATMENT AND QUARANTINE ENTOMOLOGY Effects of Methyl Bromide Concentration, Fumigation Time, and Fumigation Temperature on Mediterranean and Oriental Fruit Fly (Diptera: Tephritidae) Egg and Larval Survival

The effects of methyl bromide (MB) concentration (16, 32, 48, or 64 g/m), fumigation temperature (15, 20, 25, or 30 C), and fumigation time interactions on the survival of Mediterranean fruit ßy,Ceratitis capitata (Wiedemann), and oriental fruit ßy, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), eggs and Þrst and third instars were recorded. Increasing the fumigation temperature from 15 to 20 C or from 20 to 25 C resulted in a signiÞcant reduction in fumigation time required for equivalent egg and larval mortalities at all studied MB concentrations; no further reductions in fumigation time resulted from increasing the temperature from 25 to 30 C. Conversely, increasing temperature and time allowed for a reduction in MB concentration to obtain equivalent mortality. Thus, the optimum fumigation temperature for Mediterranean and oriental fruit ßy eggs and larvae was 25 C. Reducing MB concentrations required for phytosanitary fumigations would save time and expense, and reduce the amount of MB released into the atmosphere during aeration. Mediterranean fruit ßy was as or more tolerant to MB than oriental fruit ßy in MB tolerance for eggs and Þrst instars. The egg stage was generally more tolerant to MB regardless of concentration. However, Mediterranean fruit ßy eggs showed similar tolerance to Þrst instars at 25 C for the three highest concentrations and to third instars at 25 and30 Cfor thehighest concentration,withno signiÞcantdifferencebetween them.Therefore, eggs alone canbeused toobtainMB fumigationefÞcacy andquarantine security data at fumigation temperatures between 15 and 30 C for Mediterranean and oriental fruit ßy.