Control of Caribbean Fruit Fly (Diptera: Tephritidae) in Grapefruit by Forced Hot Air and Hydrocooling

Abstract

Mortality of Caribbean fruit fly, Anastrepha suspense (Loew), eggs and larvae in ‘Marsh’ white grapefruit, Citrus paradise Macfadyen, heated with 48 ±0.3°C forced air until center pulp temperatures were either 40–41°C or 44–45°C, was not affected by cooling the grapefruit in 10 °C water. Mortalities were 96.5 and 95.2% of immatures from hydrocooled and air-cooled grapefruits, respectively, heated to 40–41°C. Mortalities were 100% from hydrocooled and air-cooled grapefruits heated to 44–45°C. Immersing grapefruits that were heated until centers were ≤37°C produced different results. Mortalities were 13.3 and 39.5% from hydrocooled and air-cooled grapefruits, respectively, heated to 28–29°C. Mortalities were 78.1 and 83.8% from hydrocooled and air-cooled grapefruits, respectively, heated to 36–37°C. Comparisons of the mortality estimates between grapefruits hydrocooled and air cooled at both probit 5 and probit 9 were significantly different ( P ≤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°C at the center and then immersed in 10°C water.