Development of a Hydrothermal Treatment to Control Fruit Flies (Diptera: Tephritidae) and Maintain the Quality of ‘Fuyu’ Persimmons

Abstract

Because of fruit fly incidence, importing countries impose phytosanitary barriers to prevent the entry and spread of infested fruits. When fruits are not grown in fruit fly-free areas, some countries require quarantine treatments for fruit disinfestation before or during shipping. The objective of this study was to evaluate the use of a hydrothermal treatment as a quarantine treatment for ‘Fuyu’ persimmons infested with two fruit fly species to maintain fruit quality. Hot water treatment (HWT) was applied to eggs and third-instar larvae of Ceratitis capitata and Anastrepha fraterculus in vitro at 42º, 44º, 46º, 48º, and 50 ºC for 20, 30, 40, 50, 60, and 90 min. Persimmon fruit infested by C. capitata and A. fraterculus eggs and third-instar larvae were subjected to 44 ºC for 60 and 90 min, 46 °C for 20 and 30 min; and 48 °C for 20 min. Untreated infested fruits were used to estimate the rate of fruit fly infestation. Pulp firmness, skin and pulp colors, titratable acidity, pH, and total soluble solids were measured to evaluate the effect of HWT on fruit quality. The increase in temperature and immersion time decreased the pupation and emergence of adults of C. capitata and A. fraterculus in vitro. C. capitata eggs treated in vitro at temperatures ≥ 46 ºC for 30 min did not produce pupae. A. fraterculus eggs treated in vitro at 46 ºC for 20 min exhibited no larval hatching. No pupae were obtained from third-instar larvae of both fruit fly species treated at 44 ºC for 60 min. Infested ‘Fuyu’ persimmons treated at 44 ºC for 90 min did not exhibit the emergence of adults of C. capitata or A. fraterculus. Except for pH, in general, ‘Fuyu’ persimmons subjected to HWT demonstrated no alterations of skin or pulp texture, skin coloration, titratable total acidity, or total soluble solids. The results suggest that HWT is a potential quarantine treatment for the export of ‘Fuyu’ persimmons.