Phosphine-Assisted Forced Hot-Air Treatment for Phytosanitary Disinfestation of Bactrocera correcta in Mango Fruit

Bactrocera correcta is an important quarantine pest of mango, and the development of phytosanitary treatments that achieve quarantine security without compromising fruit quality remains a major challenge in fresh-fruit trade. Heat treatment is a residue-free phytosanitary option, but the temperatures required to control fruit flies often approach the tolerance limits of tropical fruit, leaving a narrow margin between quarantine security and commodity injury. In this study, a phosphine (PH₃)-assisted forced hot-air treatment was evaluated for the phytosanitary disinfestation of B. correcta in mango fruit. The developmental progression of B. correcta in mango fruit was characterized, the heat tolerance of different developmental stages was compared, and the efficacy of PH₃ followed by forced hot-air treatment (PH₃→Heat) against eggs was quantified using probit time-mortality analysis. Large-scale confirmatory validation and postharvest quality assessment were then conducted. Eggs were identified as the most heat-tolerant stage. PH₃ pre-fumigation significantly enhanced forced hot-air treatment, with 0.7 g m^-3 PH₃ providing the most practical improvement at quarantine-relevant endpoints. According to this schedule, LT_99.9968 was reduced by 44 min for heat treatment alone, from 269.0 to 224.5 min, and the large-scale validation yielded no survivors. Postharvest quality evaluation showed that PH₃→Heat did not adversely affect firmness, total soluble solids, or titratable acidity during shelf life. These results demonstrate that PH₃-assisted forced hot-air treatment is a technically feasible and commercially promising phytosanitary strategy for mango fruit.