Bactrocera dorsalis Hendel is one of the most serious pests in dragon fruit, requiring heat treatment before international trade. Here, a novel strategy of combining phosphine fumigation followed by forced hot-air treatment was developed and its effects on B. dorsalis mortality and postharvest quality of dragon fruit were evaluated. B. dorsalis 18-h-old eggs and third instar larvae were the most tolerant stages to heat treatment. The combined treatment demonstrated a significant synergistic effect. Probit analysis revealed that the heat treatment time of combined treatment required to achieve 50% mortality (95% CL) for eggs and third instar larvae was reduced to 72.5% and 66.5% of forced hot-air treatment alone, respectively. Gene expression analysis showed that phosphine fumigation dramatically inhibited induction of HSP genes in insects following forced hot-air treatment, indicating the synergistic effect might derive from the inhibition of heat-response genes by phosphine. Fruit soluble solids content and titratable acidity were not affected by the combined treatment, although respiration was slightly inhibited. This research demonstrated the synergistic effect between phosphine and forced hot-air treatment against B. dorsalis and indicated that compared to the heat treatment alone, combined treatment required less time and a lower temperature, providing great potential as a novel strategy for fruit phytosanitary treatment, especially in heat-sensitive fruit.

Bactrocera dorsalis亨德尔是火龙果中最严重的害虫之一，在国际贸易前需要热处理。在这里，开发了一种结合磷化氢熏蒸后强制热风处理的新策略，并评估了其对 B. dorsalis 死亡率和火龙果采后品质的影响。B. dorsalis 18 h 龄卵和三龄幼虫是热处理最耐受的阶段。联合治疗显示出显着的协同效应。概率分析显示，实现卵和第三龄幼虫 50% 死亡率 （95% CL） 所需的联合热处理热处理时间分别减少到单独强制热风处理的 72.5% 和 66.5%。基因表达分析表明，磷化氢熏蒸显著抑制了强制热风处理后昆虫对 HSP 基因的诱导，表明磷化氢对热响应基因的抑制可能具有协同效应。水果可溶性固形物含量和可滴定酸度不受联合处理的影响，尽管呼吸作用受到轻微抑制。本研究证明了磷化氢与强制热风处理对 B. dorsalis 的协同作用，并表明与单独的热处理相比，联合处理所需的时间更短，温度更低，作为水果植物检疫处理的新策略具有巨大潜力，尤其是在热敏性水果中。