Control of Caribbean fruit fly (Diptera: Tephritidae) in grapefruit by forced hot air and hydrocooling

Mortality of Caribbean fruit fly, Anastrepha suspensa (Loew), eggs and larvae in 'Marsh' white grapefruit, Citrus paradisi Macfadyen, heated with 48 +/- 0.3 degrees C forced air until center pulp temperatures were either 40-41 degrees C or 44-45 degrees C, was not affected by cooling the grapefruit in 10 degrees C water. Mortalities were 96.5 and 95.2% of immatures from hydrocooled and air-cooled grapefruits, respectively, heated to 40-41 degrees C. Mortalities were 100% from hydrocooled and air-cooled grapefruits heated to 44-45 degrees C. Immersing grapefruits that were heated until centers were less than or equal to 37 degrees C produced different results. Mortalities were 13.3 and 39.5% from hydrocooled and air-cooled grapefruits, respectively, heated to 28-29 degrees C. Mortalities were 78.1 and 83.8% from hydrocooled and air-cooled grapefruits, respectively, heated to 36-37 degrees C. Comparisons of the mortality estimates between grapefruits hydrocooled and air cooled at both probit 5 and probit 9 were significantly different (P less than or equal to 0.05). The probit 5 (50% mortality) estimates for immatures from hydrocooled grapefruit were 84.9 min and 68.1 min for air-cooled grapefruit. The probit 9 (99.9968% mortality) estimates for immatures were 181.7 min for hydrocooled grapefruit and 213.9 min for air-cooled grapefruit. Quarantine security was not jeopardized when grapefruit was heated to 44-45 degrees C at the center and then immersed in 10 degrees C water.