Biodegradable electrospun fibers as sustained-release carriers of insect pheromones for field trapping of Spodoptera litura (Lepidoptera: Noctuidae)

How to Control the Release Behavior of Insect Sex Pheromones Using Nanomicro Fiber: Insights from Experiment and Molecular Dynamics Simulation

Polymer-based electrospun fibers can effectively sustain pheromone release for pest control, yet their regulatory mechanisms remain unclear. In this study, fibers from various polymers were loaded with multicomponent sex pheromones of Grapholitha molesta and characterized. Release tests showed that poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PHB) fibers released 90% of pheromones in 81.93 days, compared to 14.01 days for polycaprolactone fibers. Molecular dynamics (MD) simulations revealed that pheromones diffused through the polymer network via vibrations, cavity formation, and jumping. PHB fibers exhibited the lowest diffusion coefficient (0.0064 × 10-9 m2 s-1) and highest activation energy (24.56 kJ mol-1). Additionally, PHB exhibited good crystallinity and crystal arrangement, thereby enhancing the restriction on pheromone molecules. By combining MD simulations with experimental studies, molecular structure, intermolecular forces, and crystallinity were identified as the main factors regulating the release behavior of these polymer fibers. Finally, trapping experiments confirmed their effectiveness, indicating that release studies can guide field applications.

Plant volatiles-loaded core-shell micro-nano fibers to achieve efficient and sustained bisexual attraction to pests

BACKGROUND

Chemical pesticides face significant challenges regarding their efficacy and environmental impact. Plant-based food attractants have emerged as a promising green alternative for pest control. However, their field application is limited by the short duration of effectiveness, necessitating improved carrier systems for sustained release. Electrospinning is a promising technology in this field, with core-shell fibers offering superior performance in efficient loading and sustained release compared to uniaxial fibers, highlighting their potential for further development.

RESULTS

In this study, core-shell micro-nano fiber mats were prepared via coaxial electrospinning using multiple environmentally friendly polymers. These mats were firstly and successfully loaded with food attractants bisexually attractive to Loxostege sticticalis adults, including 1-octen-3-ol, trans-2-hexenal, linalool, and anethole, enabling sustained release and effective trapping. The components in the core-shell spinning solution were chemically compatible, and after spinning, the poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/polycaprolactone (PHB/PCL) in the shell layer and polyethylene oxide (PEO) in the core layer formed core-shell fibers with clear boundaries. The mats achieved an average encapsulation efficiency of 78% for active ingredients, with a sustained release profile that delivered over 60% of the attractants within 80 days while mitigating early burst release. Electroantennogram and behavioral studies revealed that the mats retained electrophysiological activity for at least 90 days, effectively attracting male and female adult insects even after 75 days. Field trials demonstrated that the mats significantly outperformed commercial slow-release carriers, attracting a higher number of L. sticticalis adults. Additionally, the mats exhibited strong stress resistance, biodegradability, and environmental compatibility, effectively protecting active molecules while minimizing ecological impact.

CONCLUSIONS

The developed fiber mats provide a highly efficient, eco-friendly carrier for plant-based food attractants, offering prolonged efficacy and improved insect trapping performance. This study highlights their potential for sustainable agriculture and pest management, paving the way for greener alternatives to chemical pesticides.

Electrospun nanofibers as controlled release systems for the combined pheromones of Grapholita molesta and Cydia pomonella

BACKGROUND

As sex pheromones are environmentally friendly and specific, they are often used to monitor and control oriental fruit moths (OFMs). Currently, non-biodegradable polymers are commonly employed as carriers to prepare controlled sex pheromone release systems for plant protection. Electrospinning is a relatively simple technique for preparing biodegradable nanofibers that allows for the controlled release of sex pheromones. This study aimed to develop a biodegradable controlled release system for the combination of OFM pheromone and codlemone via electrospinning, in which codlemone was used as a synergist for OFM pheromone.

RESULTS

New systems for the controlled release of combined pheromones from OFM and colding moths were developed using electrospun nanofibers from polycaprolactone (PCL), cellulose acetate (CA), and polylactic acid (PLA). In the indoor experiments, the load ratio and release stability of CA nanofibers loaded with combined pheromones (CA-SP) were superior to those of the other two nanofiber types. In the field experiments, among all the treatments, 10 mg of CA-SP was the most attractive to OFMs, and its effective duration was approximately 6 weeks. The optimum storage temperature for all nanofibers was -20 °C.

CONCLUSION

Electrospun CA-SP nanofibers were biodegradable and environmentally friendly, with stable release. This study presents a new technique that could be beneficial for the monitoring and control of OFMs. © 2025 Society of Chemical Industry.

Functional Characterization of Odorant Receptors for Sex Pheromone (Z)-11-Hexadecenol in Orthaga achatina

Pheromone receptor (PR)-mediated transduction of sex pheromones to electrophysiological signals is the basis for sex pheromone communication. Orthaga achatina, a serious pest of the camphor tree, uses a mixture of four components (Z11-16:OAc, Z11-16:OH, Z11-16:Ald, and Z3,Z6,Z9,Z12,Z15-23:H) as its sex pheromone. In this study, we identified five PR genes (OachPR1-5) by phylogenetic analysis. Further RT-PCR and qPCR experiments showed that PR1-3 were specifically expressed in male antennae, while PR4 was significantly female-biased in expression. Functional characterization using the XOE-TEVC assay demonstrated that PR1 and PR3 both responded strongly to Z11-16:OH, while PR1 and PR3 had a weak response to Z3,Z6,Z9,Z12,Z15-23:H and Z11-16:Ald, respectively. Finally, two key amino acid residues (N78 and R331) were confirmed to be essential for binding of PR3 with Z11-16:OH by molecular docking and site-directed mutagenesis. This study helps understand the sex pheromone recognition molecular mechanism of O. achatina.

Nano-Micro Core-Shell Fibers for Efficient Pest Trapping

Insect sex pheromones as an alternative to chemical pesticides hold promising prospects in pest control. However, their burst release and duration need to be optimized. Herein, pheromone-loaded core-shell fibers composed of degradable polycaprolactone and polyhydroxybutyrate were prepared by coaxial electrospinning. The results showed that this core-shell fiber had good hydrophobic performance and thermal stability, and the light transmittance in the ultraviolet band was only below 40%, which provided protection to pheromones. The core-shell structure alleviated the burst release of pheromone in the fiber and extended the release time to about 133 days. In the field, the pheromone-loaded core-shell fibers showed the same continuous and efficient trapping of Spodoptera litura as the commercial carriers. More importantly, the electrospun fibers combined with biomaterials had a degradability unmatched by commercial carriers. The structure design strategy provides ideas for the innovative design of pheromone carriers and is a potential tool for the management of agricultural pests.