Using plant essential oil instead of chemical pesticides to control melon fly (Bactrocera cucurbitae (Coquillett)) is still a great challenge in agricultural practices, which must effectively slow down the volatility rate of plant essential oil. In this study, citral as a natural plant essential oil was blended with environmentally friendly castor oil based waterborne polyurethane (PU). The interaction, chemical resistance, adhesion property and sustained release behavior of the composites with different citral content were clarified, and the efficacies against the melon fly under field conditions were explored. The results indicated that the composites prepared exhibited excellent adhesion behavior on bitter gourds (Momordica charantia L.) even under rainfall washing, meanwhile the chemical resistance of composites could be tailored via controlling citral content. Low citral content composite films could be washed off by alcohol without worrying about the safety of that on crops. The composite prepared exhibited long-lasting repellent behavior against melon fly. The composite can be prepared via a simple technology and low cost, which has great value for plant essential oil applied in agriculture and can provide a new approach for melon fly control.

用植物精油代替化学农药防治瓜蝇（Bactrocera cucurbitae (Coquillett)）仍然是农业实践中的一大挑战，必须有效减缓植物精油的挥发速度。在这项研究中，柠檬醛作为一种天然植物精油与环保的蓖麻油基水性聚氨酯 (PU) 混合。阐明了不同柠檬醛含量的复合材料的相互作用、耐化学性、粘附性能和缓释行为，探索了野外条件下对瓜蝇的防治效果。结果表明，制备的复合材料对苦瓜（Momordica charantiaL.) 即使在雨水冲刷下，同时可以通过控制柠檬醛含量来调整复合材料的耐化学性。柠檬醛含量低的复合膜可以用酒精洗掉，不用担心对农作物的安全性。制备的复合材料对瓜蝇具有持久的驱避作用。该复合物制备工艺简单，成本低廉，对植物精油在农业上的应用具有重要价值，可为瓜蝇防治提供新的途径。