Diaphorina citri (Hemiptera: Liviidae) is a vector for the citrus Huanglongbing greening disease, which can reduce crop yields. Harmonia axyridis (Coleoptera: Coccinellidae) is known to prey on D. citri nymphs; we investigated the predation capacity and functional response of H. axyridis on adult D. citri. H. axyridis larvae exhibited Holling's type II functional response to different densities of adult D. citri. For second, third and fourth instar H. axyridis larvae, the successful attack rates were 0.75 ± 0.22, 1.06 ± 0.11, and 1.04 ± 0.26, respectively; the handling times were 18.08 ± 5.37, 0.45 ± 0.07, and 0.24 ± 0.07 h, respectively; and the estimated maximum predation rates were 4, 54, and 102, respectively. Fourth instar larvae had the lowest handling time. Adult H. axyridis consumed more D. citri adults maintained at 15–20°C than at 30–35°C, with an optimal temperature of 17.28°C. More adults were consumed during the day than at night, with peak consumption between 12:00 and 14:00 h, not differing significantly differ between predator genders. Adult H. axyridis reared on the aphid Acyrthosiphon pisum were tested for D. citri predation; these H. axyridis had successful attack rates, handling times, and estimated maximal predation rates of 0.66 ± 0.18, 0.82 ± 0.26 h, and 29, respectively. Conversely, those fed and tested on D. citri had corresponding rates of 0.99 ± 0.17, 0.38 ± 0.12 h, and 63, respectively. Significant H. axyridis predation on adult D. citri indicated its enhanced role in suppressing both nymph and adult D. citri.
This study presents the implementation of an evanescent field (EF)-based sensing platform employing a hybrid film composed of graphene oxide (GO) and poly(methyl methacrylate) (PMMA), integrated onto coreless D-shaped fibers (cDsFs). The operational framework of the hybrid film-coated cDsFs (GoP-cDsFs) was comprehensively elucidated through theoretical and experimental analyses. To establish a baseline for comparison, the performance of the cDsFs with the sole inclusion of the PMMA film was investigated. Our investigations underscore the substantive role of graphene oxide in augmenting the evanescent field, thereby generating a synergistic effect that contributes to the overall enhancement of the evanescent field in the device. Consequently, the fabricated GoP-cDsF sensor manifests an outstanding sensitivity of -4.936 nm/°C, rendering it particularly well-suited for applications demanding high-sensitivity temperature sensing. Moreover, the unique attributes of the GoP-cDsF position it as a promising candidate for the measurement of both magnetic and electric fields, presenting an effective strategy for multifunctional sensing applications.
Beauveria bassiana is one of the most widespread insect pathogens and can be used in the biological control of agricultural, forestry and medical pests. The mechanisms by which B. bassiana leads to mortality in different host insects are also different. For house flies, B. bassiana has strong virulence, but its microecological mechanism is not clear. In this paper, the virulence of three strains of B. bassiana (TB, CB and BB) isolated from different hosts to house flies was studied. The results showed that the three strains of B. bassiana had strong pathogenicity to house fly adults. Specifically, TB was the strongest, CB was the second strongest, and BB was the weakest, with maximum lethal effects on house fly populations 5, 6, and 7 days after infection, respectively. Further study showed that the intestinal flora of house flies was disordered 3, 4, and 5 days after B. bassiana TB, CB and BB strain infection, respectively. Intestinal flora dysbacteriosis may be an important reason for the death of house flies caused by B. bassiana . After infection, the negative interaction ratio of bacteria in the house fly intestine decreased, and the stronger the virulence was, the lower the negative interaction ratio was. The time from B. bassiana infection to intestinal flora dysbacteriosis was not fixed. We named this period the “spring stage”. The stronger the virulence of the B. bassiana strain was, the shorter the “spring stage” was. Therefore, the “spring stage” can be used as a virulence marker for evaluating the pathogenicity of different B. bassiana strains.
Abstract Satsuma mandarin is one of the most widely cultivated citrus in the world. In this study, we firstly presented the complete chloroplast genome of Satsuma mandarin by using BGISEQ-500 sequencing technology. The complete chloroplast genome of Satsuma mandarin is 160,699 bp in size, including a pair of inverted repeat regions of 26,990 bp, a large single copy region of 87,918 bp, and a small single copy region of 18,801 bp. The complete chloroplast genome of Satsuma mandarin contains 108 unique genes, including 75 protein coding genes, 29 tRNA genes and 4 rRNA genes. Phylogenetic analysis based on the complete chloroplast genome showed that the relationship between Satsuma mandarin and citrus reticulate was the closest.
Citrus melanose, caused by Diaporthe citri, is one of the most economically significant fungal diseases in China. Given that the application of fungicides is the main technique used for the control of citrus melanose, many studies have focused on enhancing the effectiveness and efficiency of the use of fungicides for the control of this economically significant disease. Here, we developed a TaqMan quantitative polymerase chain reaction (qPCR) protocol for monitoring citrus melanose via detection of suspected infected leaves and airborne conidia of D. citri. A primer pair and TaqMan probe targeting D. citri were designed to amplify a region of the fungal β-tubulin gene. The limits of detection and quantification of our TaqMan qPCR method were 159.57 and 683 copies/μL, respectively. The method detected the DNA equivalent to 47 conidia when fungal conidia were cultured in vitro. To evaluate the feasibility of our TaqMan qPCR method, symptomatic and asymptomatic leaf samples, airborne conidia samples were collected from a citrus orchard and tea garden, respectively. D. citri was detected in leaves with citrus melanose symptoms in an orchard; airborne fungal conidia of D. citri were also detected. These findings suggested that this novel TaqMan qPCR method could be used to detect D. citri both in vivo and in vitro. Our methodology could be applied as an alternative method for monitoring the changes in the incidence of D. citri in orchards.
We present the first-ever demonstration of an evanescent field-based sensing structure utilizing a graphene oxide (GO)/poly(methyl methacrylate) (PMMA) hybrid film integrated on coreless D-shaped fibers (cDsFs). Theoretical and experimental analyses were conducted to elucidate the internal working mechanism of the hybrid film-coated cDsF (GoP-cDsF). Additionally, the performance of the cDsF with the PMMA film alone was employed as a reference for comparison. Our findings underscore the significant role played by the GO in enhancing the evanescent field, leading to a synergistic effect that contributes to the overall enhancement of the device's evanescent field. Consequently, the as-fabricated GoP-cDsF sensor demonstrates a remarkable sensitivity of -4.936 nm/°C, making it highly suitable for high-sensitivity temperature sensing applications. Furthermore, these attributes position the GoP-cDsF as a promising candidate for measuring both magnetic and electric fields, thereby offering a viable strategy for multifunctional sensing applications.
Mancozeb is extensively used fungicide to prevent citrus melanose in most Asian countries, especially in China. So far, however, there have been no reports of thet effect of Mancozeb on the citrus rhizosphere bacterial community. Therefore, this comparative experiment defined the genomic and functional related to community and soil health of 2-years old Citrus unshiu Marc. rhizosphere through amplicon sequencing and chemical analysis. This study evaluated the effect of mancozeb on the chemical properties of citrus-cultivated soil and the richness and diversity of rhizosphere bacterial community. We also investigated the abundance response of rhizosphere bacterial groups to 0, 2, 4, 6 and 8 times application of 2 g mancozeb (active ingredient content, ai.) 600 times diluted with water. Our data revealed that the abundance of rhizosphere-associated bacterial species increased significantly after planting citrus. The relative abundance of Candidatus, Saccharibacteria, Parcubacteria, and Proteobacteria increased with the increase in mancozeb watering times. Meanwhile, the abundance of Nitrospirae decreased with the increase in mancozeb application times. The findings indicated that the chemical properties of the soil and the richness and diversity of rhizosphere bacterial community did not significantly differ across the mancozeb gradients in soil.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)