Jinfeng Hu

The Asian citrus psyllid (Diaphorina citri) serves as the principal insect vector responsible for the transmission of citrus Huanglongbing (HLB). Consequently, the effective control of D. citri is of paramount importance for curbing the spread of this devastating disease. Fir essential oil (FEO) exhibits a potent repellent activity against D. citri; however, its practical application is severely constrained by a short duration of efficacy arising from its high volatility. Imidacloprid (Im) is a conventional insecticide widely used for D. citri management, and prolonging its residual activity remains a critical challenge for field application. In this study, we synthesized dendritic mesoporous silica nanoparticles (DMSNs, ≈257 nm) and employed them to construct a nano-pesticide formulation co-loaded with both Im and FEO. Our results demonstrated that DMSNs possessed high loading capacities for Im (21.79%) and FEO (32.98%). Notably, both Im and FEO within the DMSNs-Im-FEO formulation exhibited favorable sustained-release profiles and significantly extended residual activities compared to their free counterparts. Furthermore, the DMSNs-Im-FEO formulation displayed preliminary non-target tolerance in citrus plants, Chinese milk vetch, and earthworms, indicating its low ecotoxicological risk. Overall, our study provides a novel and promising strategy for the sustainable management of D. citri, which holds considerable significance for the integrated management of HLB.

Neonicotinoid insecticides (NIs) improve crop yield but raise environmental and health concerns. This review describes residues of 13 commercial NIs and their transformation products (TPs) in water, soil, air, vegetables, fruits, tea, and animal-derived foods. It also summarizes risks to nontarget organisms (aquatic species, soil invertebrates, and bees) and humans. NIs disrupt neuronal signaling in nontarget species, suggesting their ecological risks are substantially underestimated. Halogenated NIs show marked environmental persistence. Unexpectedly, all parent NIs and their TPs display high mobility. Six parent NIs and 70.45% of TPs show nontarget toxicity. Notably, 27.24% of neonicotinoid insecticide TPs (excluding dinotefuran’s TPs) simultaneously exhibit strong persistence, high mobility, and nontarget toxicity. These threats to ecosystems should not be overlooked. The review proposes forward-looking recommendations for next-generation NIs. Overall, this work provides critical insights into NIs toxicity and ecological impacts, offering valuable guidance for mitigating environmental contamination.

Early, rapid, and accurate detection methods are critical for the prevention and control of citrus Huanglongbing (HLB). This study proposes an intelligent rapid detection framework for HLB that integrates Fourier Transform Infrared Spectroscopy (FT-IR) with a deep neural network model combining band fusion priors and attention mechanisms. To enhance the feature learning capability of FT-IR, this study designed and developed a CNN-LSTM model (1DConvLSTM-SA) incorporating dual enhancements via band priors and attention mechanisms. The BandMask (BM) module leverages input band prior information to weight and amplify the absorbance at corresponding wavelengths in FT-IR, thereby guiding the model to focus on sensitive bands that are highly correlated with HLB infection characteristics. The self-attention (SA) module further refines deep spectral features. 1DConvLSTM-SA was trained on FT-IR data and achieved outstanding performance, with an accuracy of 94.1% on the independent Tangelo test set and 93.4% on the independent test sets of the other nine citrus varieties. Furthermore, compared with traditional quantitative polymerase chain reaction (qPCR) methods, this approach reduces costs by 67.4% and testing time by 94.8%. It provides an efficient, cost-effective and promising technical solution for rapid HLB diagnosis, underscoring the broad prospects of AI-driven FT-IR spectral analysis in agricultural disease detection.

Nanozinc oxide (ZnO) is a known material for its high therapeutic efficacy against citrus canker. However, the influence of particle size on the antibacterial activity of nano-ZnO against Xanthomonas citri subsp. citri (Xcc), as well as the distinct bacterial response mechanisms to different nanoparticle sizes, remain poorly understood, limiting its broader application. In this study, differences in the antibacterial potentials of nano-ZnO particles with sizes of 30, 90, and 200 nm against Xcc were investigated. The results showed that the zeta potential of the three nano-ZnO variants displayed no significant differences. However, the antibacterial efficacy of nano-ZnO against Xcc was strongly dependent on particle size, with smaller particles exhibiting greater antibacterial activity. This is attributed to their increased capacity to damage bacterial cell membranes and DNA, which is linked to a higher generation of reactive oxygen species and greater release of Zn²⁺ within the bacterial cells. In addition, small-sized nano-ZnO exhibits superior efficacy in inhibiting biofilm formation, exopolysaccharide secretion, and xanthomonadin production in Xcc. Fourier transform infrared multivariate and two-dimensional correlation analyses revealed that macromolecular components in Xcc exhibited more pronounced responses to smaller-sized nano-ZnO particles, further supporting their superior antibacterial efficacy. In conclusion, this study provides valuable insights into the size-dependent antibacterial mechanisms of nanomaterials and offers a theoretical basis for the effective application of nano-ZnO in the control of citrus canker.

BACKGROUND: Citrus canker, a bacterial disease caused by Xanthomonas citri subsp. citri (Xcc), is one of the major threats to the citrus industry. Inorganic copper (Cu) formulations such as Bordeaux mixture and Kocide 3000 are currently used to control citrus canker; however, they are poorly water‐soluble and have negligible plant transport, making the systemic treatment of citrus canker difficult.RESULTS: This study synthesized Cu₂O@His by one‐pot self‐assembly of Cu²⁺ and histidine for controlling citrus canker. The results showed that Cu₂O@His had a uniform size distribution (≈2.7 nm) and good water solubility. It could disrupt the cell membrane of Xcc and enter into the bacterial cells to destroy the DNA, thereby inhibiting the growth (half maximal inhibitory concentration = 7.4 μg mL⁻¹) and production of virulence factors of Xcc. This was attributed to its excellent dispersibility and reactive oxygen species‐inducing ability. The therapeutic efficacy and plant transport of Cu₂O@His were much better than those of Kocide 3000. Additionally, it had remarkable biosafety for citrus plants and earthworms (lethal concentration 50% >> 40 mg kg⁻¹).CONCLUSION: This study provides a new, eco‐friendly and more efficient option for citrus canker control. © 2025 Society of Chemical Industry.

Azole and benzimidazole fungicides are widely used agrochemicals to prevent and treat fungal growth and are frequently detected in aquatic environments. Here, we aimed to assess the aquatic ecological risks of ten currently used azole and benzimidazole fungicides, which with the aryl hydrocarbon receptor (AhR) agonistic activity, and their transformation products (TPs). We obtained over 400 types of aerobic TPs for ten fungicides. Some fungicides and their TPs (approximately 26.7%) exhibited the potential AhR agonistic activity and toxicity to different aquatic species. Meanwhile, some compounds with the chlorine element and benzene ring structure exhibited environmental persistence and mobile ability. Several of them were frequently detected in aquatic environments, posing potential risks to aquatic ecosystems. These harmful fungicides and their TPs should be given attention. This study provides important insight into the aquatic ecological risks caused by azole and benzimidazole fungicides, which can provide theoretical guidance for their pollution control.

BACKGROUND: Diaphorina citri Kuwayama is the main vector of the Huanglongbing (HLB) pathogen Candidatus Liberibacter asiaticus ( C Las). Therefore, reducing C Las acquisition by D. citri is crucial for controlling the spread of HLB. RESULTS: This study aimed to investigate the effect of ZnO quantum dots (ZnO QDs) on C Las acquisition by D. citri . The results showed that ZnO QDs were absorbed by citrus plants and D. citri , inducing reactive oxygen species generation in the intestine and causing intestinal cell apoptosis. The uptake rate of C Las was reduced to 75% and 22.3% after treatment with 2 and 5 mg ∙ mL ⁻¹ ZnO QDs, respectively, compared with 100% in the control group. Transcription analysis showed significant changes in the expression of D. citri genes related to apoptosis, oxidative stress, and DNA replication and repair. CONCLUSION: The results suggested that ZnO QDs could efficiently reduce C Las acquisition by D. citri , providing a safe and reliable tool for HLB prevention and control. © 2024 Society of Chemical Industry.

Empoasca onukiiis a major pest that attacks tea plants. To seek effective and sustainable methods to control the pest, it is necessary to assess its host preference among different species of tea and understand the critical factors behind this behavior. In this study, the behavioral preference ofE. onukiifor volatile organic compounds (VOCs) of three potted tea species was evaluated. The VOCs released by the three tea species were analyzed using gas chromatography-mass spectrometry, and the major components were used to test the pest’s preference. Transcriptome analysis was used to infer the key genes that affect the biosyntheses of the VOCs. The results showed that the tendency ofE. onukiitoward the VOCs of the three tea species was the strongest in green tea, followed by white tea, and the weakest in red tea. This behavioral preference was significantly and positively correlated with the relative levels of hexanol, linalool, and geraniol in tea volatiles. Relative hexanol was significantly and positively correlated with the expression of genesTEA009423 (LOX2.1),TEA009596 (LOX1.5),TEA008699 (HPL),TEA018669 (CYPADH), andTEA015686 (ADHIII). Relative linalool was significantly and positively correlated with the expression of genesTEA001435 (CAD)andCamellia_sinensis_newGene_22126 (TPS). Relative geraniol was significantly and positively correlated with the expression of genesTEA001435 (CAD),TEA002658 (CYP76B6),TEA025455 (CYP76T24), andCamellia_sinensis_newGene_22126 (TPS). The above findings suggested that three volatiles (hexanol, linalool, and geraniol) determined the behavioral preference ofE. onukiitoward tea plants, and their biosynthesis was mainly affected by nine genes (TEA009423,TEA009596,TEA008699,TEA018669,TEA015686,TEA001435,TEA002658,TEA025455, andCamellia_sinensis_newGene_22126).

The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is an economically important pest of crops worldwide. A M. persicae (SEF-R) population from a cabbage field in southeastern China was tested for susceptibilities to 13 insecticides. Compared with the susceptible clone (FFJ-S), extremely high and high-resistance to beta-cypermethrin (324-fold) and imidacloprid (106.9-fold) were detected in SEF-R. More importantly, this is the first report of resistance in field M. persicae population to sulfoxaflor, flupyradifurone, pymetrozine, spirotetramat, flonicamid, and broflanilide in China. The resistance factor decayed to a low level to sulfoxaflor and pymetrozine after 15 generations without any selection pressure. The resistance-related mutations (R81T and kdr) were detected in SEF, conferring target-site resistance to neonicotinoids and pyrethroids, respectively. Biochemistry bioassays confirmed the involvement of monooxygenase enzyme, carboxylesterase, superoxide dismutase and peroxidase in multi-insecticide resistance mechanism. The overexpression of P450s, esterases, and a UDP-glycosyltransferase, might be responsible for the multi-insecticide resistance in SEF-R. The knockdown of CYP6CY3 in SEF-R increased its susceptibility to imidacloprid, thiacloprid, and thiamethoxam, which verified that P450s play vital roles in neonicotinoid metabolism. This study will be helpful for chemical control, as well as for resistance monitoring and management of GPA, in China.