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BACKGROUND: Citrus huanglongbing (HLB) is a devastating disease caused by Candidatus Liberibacter asiaticus (CLas) that affects the citrus industry. In nature, CLas relies primarily on Diaphorina citri Kuwayama as its vector for dissemination. After D. citri ingests CLas‐infected citrus, the pathogen infiltrates the insect's body, where it thrives, reproduces, and exerts regulatory control over the growth and metabolism of D. citri. Previous studies have shown that CLas alters the composition of proteins in the saliva of D. citri, but the functions of these proteins remain largely unknown. RESULTS: In this study, we detected two proteins (DcitSGP1 and DcitSGP3) with high expression levels in CLas‐infected D. citri. Quantitative PCR and Western blotting analysis showed that the two proteins were highly expressed in the salivary glands and delivered into the host plant during feeding. Silencing the two genes significantly decreased the survival rate for D. citri, reduced phloem nutrition sucking and promoted jasmonic acid (JA) defenses in citrus. By contrast, after overexpressing the two genes in citrus, the expression levels of JA pathway‐associated genes decreased. CONCLUSION: Our results suggest that CLas can indirectly suppress the defenses of citrus and support feeding by D. citri via increasing the levels of effectors in the insect's saliva. This discovery facilitates further research into the interaction between insect vectors and pathogens. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Panonychus citri and Diaphorina citri are serious citrus pests (mites) in many countries. The predatory mite Neoseiulus cucumeris can prey on both P. citri and D. citri. It is necessary to develop a strategy using predatory mites and selective pesticides that can simultaneously control both pests effectively and sustainably. The toxicities of matrine and abamectin to P. citri, D. citri and N. cucumeris were evaluated in the laboratory. Matrine was highly lethal to D. citri and relatively less toxic to P. citri and N. cucumeris. Abamectin was relatively less toxic to D. citri. The results of the field trials demonstrated the ecological control strategy that combined the release of predatory mites and applications of four matrine sprays from June 2011 to November 2011, which provided better control over P. citri than pesticide applications alone with six sprays during the same period. It achieved similar control levels for D. citri. In Matrine + N. cucumeris orchard, the total number of spiders was significantly larger than that in the Pesticides Only orchard, but the total number of predatory mites was lower. It is inferred that primarily natural enemies and matrine together play a role in controlling citrus pests. [ABSTRACT FROM AUTHOR]

Flow properties in a liquid-solid fluidized bed were simulated by means of an Euler-Euler two-fluid model. A κ - ε turbulent model was used to simulate the flow behavior of liquid by considering the couplings between liquid and solid phases. The effect of liquid properties of density and viscosity upon flow properties was studied in the liquid-solid fluidized bed. Results show that the mixing of liquid and particles is uniform in the liquid-solid fluidized bed, and it exhibits a homogenous fluidization. The axial velocities of particles increase with the increase of liquid density and viscosity, and they both have the same trends in the bed. The simulation result of bed's expanding heights is in an agreement with the calculation results of Balm et al.. [ABSTRACT FROM AUTHOR]