Pine wilt disease is a devastating forest disaster caused by Bursaphelenchus xylophilus, which has brought inestimable economic losses to the world’s forestry due to lack of effective prevention and control measures. In this paper, a porous structure CuBTC was designed to deliver avermectin (AM) and a control vector insect Japanese pine sawyer (JPS) of B. xylophilus, which can improve the biocompatibility, anti-photolysis and delivery efficacy of AM. The results illustrated the cumulative release of pH-dependent AM@CuBTC was up to 12 days (91.9%), and also effectively avoided photodegradation (pH 9.0, 120 h, retention 69.4%). From the traceable monitoring experiment, the AM@CuBTC easily penetrated the body wall of the JPS larvae and was transmitted to tissue cells though contact and diffusion. Furthermore, AM@CuBTC can effectively enhance the cytotoxicity and utilization of AM, which provides valuable research value for the application of typical plant-derived nerve agents in the prevention and control of forestry pests. AM@CuBTC as an environmentally friendly nanopesticide can efficiently deliver AM to the larval intestines where it is absorbed by the larvae. AM@CuBTC can be transmitted to the epidemic wood and dead wood at a low concentration (10 mg/L).

The ectoparasitoid Dastarcus helophoroides Fairmaire (Coleoptera: Bothrideridae) is an important natural enemy insect, which is artificially mass-reared and released into woodland to control medium and large longhorn beetle species. This study examined the developmental duration (days) of larvae and adult fitness (including numbers of adults emerging per host and mean body size) by exposing a single substitute host, a pupa of Zophobas morio (Coleoptera: Tenebrionidae), to different densities of D. helophoroides larvae. We showed that there was no significant effect on the rate of successful parasitism and cocoon formation, but emergence success and measures of individual adult body size (length, width, and weight) declined with increasing larval density. Larval period and cocoon period increased with larval density, while total weight of adults emerging per host increased initially before reaching a plateau. Our results suggest that a pupa of Z. morio could be successfully parasitized by a single D. helophoroides larva, but multiple D. helophoroides larvae can share one host. Excessive larval density caused intraspecific competition among D. helophoroides larvae, manifesting in extended developmental duration of immature stage and reduced fitness of adults. Furthermore, the tradeoff between the numbers of adults and body size may stabilize the population dynamics with detectable mutual interference, particularly in competing for limited host resources. These findings suggest six larvae per host would achieve the highest adult fitness and would enhance mass-rearing techniques as part of IPM strategies for longhorn beetles.

As a vector of pine wood nematode disease, Monochamus alternatus is wood-boring, cryptic, and extremely difficult to control—features that have made them a disastrous problem. In this study, we present a method of scanning the galleries of Monochamus alternatus using CT (computed tomography) technology to obtain their systematic structure via 3D (three-dimensional) reconstruction, so as to clarify the gallery types and their structural parameters. TLC (thin-layer chromatography) scanning on wood segments damaged by M. alternatus was performed using a 128-row spiral CT GE Revolution EVO to obtain 64-layer CT scanned images. From the scanned images, we were able to clearly identify the beetle larvae and their galleries. The galleries were clearly delineated from the peripheral xylem, except for parts that were blocked by a frass–feces mixture, which were slightly blurred. Three-dimensional reconstruction of the galleries showed that most of the gallery types were C-shaped, and a few were S-shaped or Y-shaped. There was only one larva per gallery, and the galleries were separate. The vicinity of the entrance hole and the anterior part of the pupal chamber were blocked with a frass–feces mixture. There were no significant differences among the galleries’ parameters, such as the width of the entrance holes, tunneling depth, vertical length, blockage length and volume, total length of the galleries, and boring volume. With MIMICS (Materialise’s interactive medical image control system) image processing software, the images of each layer were made into a composite image, providing an effective way to visualize the 3D distribution of galleries. Using the methodology outlined in this study, both a single gallery structure and the spatial distribution of multiple galleries of M. alternatus can be shown, and the specific parameters of galleries can also be accurately calculated, which provides new ideas and methods for carrying out ecological and scientific research and precise prevention and control techniques of M. alternatus.

Mangrove ecosystems represent critical coastal blue carbon sinks, whose ecological stability is essential for sustaining carbon sequestration capacity and coastal ecological security. Hyblaea puera, a dominant defoliating pest in mangrove habitats, exhibits abrupt population outbreaks and extreme destructive potential, severely threatening the integrity of blue carbon ecosystems. While conventional broad-spectrum chemical insecticides deliver adequate control efficacy, they often exert detrimental effects on non-target organisms and adjacent coastal marine environments, conflicting with core mangrove conservation objectives. Azadirachtin, a botanical insecticide with high lepidopteran target highly selective, is a promising eco-friendly alternative; nevertheless, the dual stresses of periodic tidal flushing and intense ultraviolet radiation in intertidal mangrove habitats drive rapid photodegradation and leaching loss of azadirachtin, leading to poor field persistence and slow lethal action of the free formulation. These limitations render neat azadirachtin insufficient to meet the urgent demand for rapid emergency control of H. puera during population outbreaks. To address these technical bottlenecks, we developed an azadirachtin-loaded dendritic mesoporous silica nanoparticle delivery system to simultaneously improve the environmental stability and fast-acting insecticidal efficacy of azadirachtin against H. puera. Specifically, dendritic mesoporous silica nanoparticles (DMSNs) were synthesized via a one-pot method, then loaded with azadirachtin (ADT) and further surface-modified with polyether-modified heptamethyltrisiloxane (PM) to fabricate the ADT@DMSN/PM nano-delivery system. The physicochemical properties, intertidal habitat adaptability, insecticidal activity, and environmental safety of the fabricated system were systematically evaluated. Characterization results showed that the as-synthesized DMSNs had a uniform particle size of 200–300 nm, a specific surface area of 260.99 m²/g, and an ADT loading efficiency of 66.6%. ADT@DMSNs exhibited prominent alkaline-responsive sustained-release behavior, with a cumulative ADT release of 57.0% at pH 8.2 (mangrove seawater conditions) over 500 h. Laboratory bioassays revealed that the 24 h median lethal concentrations (LC₅₀) of ADT@DMSNs against third-, fourth-, and fifth-instar H. puera larvae were 84.36, 188.08, and 458.65 μg/mL, respectively, representing 2.38-, 2.63-, and 2.86-fold enhancements in insecticidal activity compared with free ADT. After modification with the PM adjuvant, the nanoformulation exhibited a significantly reduced contact angle on Avicennia marina leaves, over 3-fold higher foliar penetration efficiency, and markedly improved tidal wash-off resistance. Field cage bioassays demonstrate that the ADT@DMSN/PM nanoformulation yields a corrected mortality of approximately 95% against H. puera larvae at 1200 mg/L at 24 h. This nano-delivery system is precisely tailored to the unique environmental constraints of mangrove intertidal habitats, offering a novel eco-friendly technical approach to achieve rapid emergency control of H. puera outbreaks.