scholarly journals Drench Application of Systemic Insecticides Disrupts Probing Behavior of Diaphorina citri (Hemiptera: Liviidae) and Inoculation of Candidatus Liberibacter asiaticus

Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 314 ◽  
Author(s):  
Michele Carmo-Sousa ◽  
Rafael Brandão Garcia ◽  
Nelson Arno Wulff ◽  
Alberto Fereres ◽  
Marcelo Pedreira Miranda
Keyword(s):  
Transmission Rate ◽  
Transmission Efficiency ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Electrical Penetration Graph ◽  
Systemic Insecticides ◽  
Probing Behavior ◽  
Candidatus Liberibacter ◽  
Inoculation Access Period ◽  
Liberibacter Asiaticus

Candidatus Liberibacter asiaticus (CLas) is a phloem-limited bacterium that is associated with the Huanglongbing (HLB) disease of citrus and transmitted by the psyllid, Diaphorina citri. There are no curative methods to control HLB and the prevention of new infections is essential for HLB management. Therefore, the objective of our study was to determine the effects of systemic insecticides, such as the neonicotinoids imidacloprid, thiamethoxam, and a mixture of thiamethoxam and chlorantraniliprole (diamide) on the probing behavior of CLas-infected D. citri and their effect on CLas transmission. The electrical penetration graph (EPG-DC) technique was used to monitor the stylet penetration activities of CLas-infected D. citri on sweet orange [Citrus sinensis (L.) Osbeck] ‘Valencia’ treated with systemic insecticides. Systemic insecticides disrupted the probing behavior of CLas-infected D. citri, in a way that affected CLas transmission efficiency, particularly by negatively affecting the stylet activities related to the phloem phase. All insecticides reduced (by 57–73%) the proportion of psyllids that exhibited sustainable phloem ingestion (waveform E2 > 10 min), with significant differences observed on plants treated with thiamethoxam and thiamethoxam + chlorantraniliprole. The transmission rate of CLas with high inoculum pressure (five CLas-infected D. citri per plant and a seven-day inoculation access period) to untreated control plants was 93%. In contrast, CLas transmission was reduced to 38.8% when test plants were protected by systemic insecticides. Our results indicated that all insecticides tested presented a potential to reduce CLas inoculation by an average of 59%; therefore, these insecticides can be used to reduce the spread of HLB.

scholarly journals Temporal Progression of ‘Candidatus Liberibacter asiaticus’ Infection in Citrus and Acquisition Efficiency by Diaphorina citri

2014 ◽  
Vol 104 (4) ◽  
pp. 416-421 ◽  
Author(s):  
Helvecio D. Coletta-Filho ◽  
Matthew P. Daugherty ◽  
Cléderson Ferreira ◽  
João R. S. Lopes
Keyword(s):  
Transmission Efficiency ◽  
Management Tool ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Infection Level ◽  
Plant Infection ◽  
Citrus Production ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Asymptomatic Phase

Over the last decade, the plant disease huanglongbing (HLB) has emerged as a primary threat to citrus production worldwide. HLB is associated with infection by phloem-limited bacteria (‘Candidatus Liberibacter’ spp.) that are transmitted by the Asian citrus psyllid, Diaphorina citri. Transmission efficiency varies with vector-related aspects (e.g., developmental stage and feeding periods) but there is no information on the effects of host–pathogen interactions. Here, acquisition efficiency of ‘Candidatus Liberibacter asiaticus’ by D. citri was evaluated in relation to temporal progression of infection and pathogen titer in citrus. We graft inoculated sweet orange trees with ‘Ca. L. asiaticus’; then, at different times after inoculation, we inspected plants for HLB symptoms, measured bacterial infection levels (i.e., titer or concentration) in plants, and measured acquisition by psyllid adults that were confined on the trees. Plant infection levels increased rapidly over time, saturating at uniformly high levels (≈108 copy number of 16S ribosomal DNA/g of plant tissue) near 200 days after inoculation—the same time at which all infected trees first showed disease symptoms. Pathogen acquisition by vectors was positively associated with plant infection level and time since inoculation, with acquisition occurring as early as the first measurement, at 60 days after inoculation. These results suggest that there is ample potential for psyllids to acquire the pathogen from trees during the asymptomatic phase of infection. If so, this could limit the effectiveness of tree rouging as a disease management tool and would likely explain the rapid spread observed for this disease in the field.

Probing the application of OmpA-derived peptides to disrupt the acquisition of ‘Candidatus Liberibacter asiaticus’ by Diaphorina citri

2021 ◽  
Author(s):  
Marcus Vinicius Merfa e Silva ◽  
Eduarda Regina Fischer ◽  
Mariana de Souza e Silva ◽  
Carolina Sardinha Francisco ◽  
Helvécio Coletta-Filho ◽  
...  
Keyword(s):  
Control Strategies ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
In Planta ◽  
Host Interaction ◽  
Vector Population ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Bacterial Outer Membrane

Huanglongbing (HLB) is currently the most devastating disease of citrus worldwide. Both bacteria ‘Candidatus Liberibacter asiaticus’ (CLas) and ‘Ca. Liberibacter americanus’ (CLam) are associated with HLB in Brazil, but with a strong prevalence of CLas over CLam. Conventionally, HLB management focuses on controlling the insect vector population (Diaphorina citri; also known as Asian citrus psyllid – ACP) by spraying insecticides, an approach demonstrated to be mostly ineffective. Thus, development of novel more efficient HLB control strategies is required. The multifunctional bacterial outer membrane protein OmpA is involved in several molecular processes between bacteria and their hosts and has been suggested as a target for bacterial control. Curiously, OmpA is absent in CLam in comparison to CLas, suggesting a possible role on host-interaction. Therefore, in the current study, we have treated ACPs with different OmpA-derived peptides aiming to evaluate the acquisition of CLas by the insect vector. Treatment of psyllids with 5 µM of Pep1, Pep3, Pep5 and Pep6 in artificial diet significantly reduced the acquisition of CLas, while increasing the concentration of Pep5 and Pep6 to 50 µM abolished this process. In addition, in planta treatment with 50 µM of Pep6 also significantly decreased the acquisition of CLas and sweet orange plants stably absorbed and maintained this peptide for as long as three months post the final application. Together, our results demonstrate the promising use of OmpA-derived peptides as a novel biotechnological tool to control CLas.

Population diversity of “Candidatus Liberibacter asiaticus” and Diaphorina citri in Sichuan: A case study for Huanglongbing monitoring and interception

Plant Disease ◽  
2021 ◽  
Author(s):  
Xuejin Cui ◽  
Kehong Liu ◽  
Jie Huang ◽  
Shimin Fu ◽  
Qingdong Chen ◽  
...  
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Control Strategies ◽  
Population Diversity ◽  
Mitochondrial Genomes ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Multiple Sources ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Citrus Huanglongbing (HLB) is present in 10 provinces in China and is associated with “Candidatus Liberibacter asiaticus” (CLas), which is transmitted by the Asian citrus psyllid (Diaphorina citri, ACP). To date, HLB and ACP have expanded to Yibin city of Sichuan Province, posing an imminent threat to the citrus belt of upper and middle reach of Yangtze River, an important late maturing citrus-producing area in China. To understand the epidemiological route of CLas and ACP in newly invaded regions of Sichuan and thereby better establish an HLB-interception zone ranging from Leibo to Yibin, we evaluated the molecular variability of 19 CLas draft genomes from citrus or dodder (Cuscuta campestris). They include three type-specific prophage loci, three variable numbers of tandem repeat (VNTR) loci, a miniature inverted-repeat transposable element (MITE) types, and population diversity of 44 ACP mitochondrial genomes. The results indicated that CLas isolates in the newly invaded area (Pingshan) were more diverse than those in the HLB endemic areas (Leibo and Ningnan). Phylogenetic analysis based on mitochondrial genomes demonstrated that ACPs in Leibo, Pingshan and Xuzhou (rural areas) represent a new group (MG4), distinguished by the three unique SNPs in cox1, nad4 and cytb. However, the ACPs sampled from the urban areas of Cuiping and Xuzhou belonged to the southeastern China group (MG2-1). Altogether, our study revealed multiple sources of ACP and CLas in the HLB-interception zone and proposed their transmission route. This study contributes to the formulation of precise HLB prevention and control strategies in the HLB-interception zone in Sichuan and could be useful for HLB management efforts in other regions.

A Review of Huanglongbing (Citrus Greening) Management in Citrus Using Nutritional Approaches in China

2011 ◽  
Vol 12 (1) ◽  
pp. 24 ◽  
Author(s):  
Yulu Xia ◽  
Gecheng Ouyang ◽  
Ronald A. Sequeira ◽  
Yu Takeuchi ◽  
Ignacio Baez ◽  
...  
Keyword(s):  
Nutrient Management ◽  
Field Survey ◽  
Cultural Practices ◽  
Sweet Orange ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Maxima ◽  
Liberibacter Asiaticus

The Asian form of huanglongbing (HLB) is caused by ‘Candidatus Liberibacter asiaticus (Las),’ a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama. Nutrient management, together with other cultural practices such as pruning and irrigation, for mitigation of the disease has been practiced in China for many years. Our literature review, field survey, and interviews with Chinese scientists and growers indicate that these cultural practices were generally ineffective for the disease management. However, a nutritional approach in conjunction with other cultural practices such as irrigation can maintain grove productivity for a certain time depending on the type of citrus species/cultivars, the age of the trees, the propagation method of the plants, the Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) population, and other factors. Symptomatic mature pommelo (Citrus maxima Merr) and sweet orange (C. sinensis L. Osbeck) plants can commonly survive and maintain a certain level of productivity for an additional 4 to 5 years, even longer assuming vigorous ACP control. Accepted for publication 27 June 2011. Published 3 October 2011.

scholarly journals Tracing Penicillin Movement in Citrus Plants Using Fluorescence-Labeled Penicillin

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 262
Author(s):  
Nabil Killiny ◽  
Pedro Gonzalez-Blanco ◽  
Yulica Santos-Ortega ◽  
Fuad Al-Rimawi ◽  
Amit Levy ◽  
...  
Keyword(s):  
Vascular Tissue ◽  
Vascular System ◽  
Citrus Greening ◽  
Application Site ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Industry ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Huánglóngbìng (HLB), citrus greening, is one of the most destructive diseases of citrus plants worldwide. In North America, HLB is caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus and is transmitted by the Asian citrus psyllid, Diaphorina citri. No cure exists at present, and the use of antibiotics for the control of HLB has gained interest due to the significant losses to the citrus industry. Because of unsatisfactory results when using foliar applications of antibiotics, concerns were raised regarding the uptake and translocation of these materials within trees. We, therefore, investigated a method that allows us to study the movement of antibiotic materials in citrus plants. Herein, we utilized a fluorescence-labeled penicillin, BOCILLIN™ FL-Penicillin (FL-penicillin), to study the uptake and translocation of penicillin in citrus plants. FL-penicillin was applied by puncture to the stem of young citrus seedlings and was traced by using fluorescence microscopy. After application, we detected FL-penicillin in the leaves and in the stem xylem and phloem tissues above and below the application site in both intact and partially bark-girdled citrus seedlings, indicating that it is easily taken up and transported through the plant vascular system. In addition, we detected FL-penicillin in the gut of D. citri, which were allowed to feed on the treated plants, suggesting translocation of this molecule into the vascular tissue. We propose that the use of fluorescent-labeled molecules could be an effective tool for understanding the uptake and translocation of antibiotics and other macromolecules in plants and insects.

scholarly journals Probing Behavior of Diaphorina citri (Hemiptera: Liviidae) on Valencia Orange Influenced by Sex, Color, and Size

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Timothy A Ebert ◽  
Michael E Rogers
Keyword(s):  
Body Size ◽  
Model Performance ◽  
Diaphorina Citri ◽  
Probing Behavior ◽  
Valencia Orange ◽  
Improve Model ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Improve Model Performance

Abstract Candidatus Liberibacter asiaticus Jagoueix, Bové, and Garnier (Rhizobiales: Rhizobiaceae) is transmitted by the psyllid Diaphorina citri Kuwayama and putatively causes Huanglongbing disease in citrus. Huanglongbing has reduced yields by 68% relative to pre-disease yields in Florida. Disease management is partly through vector control. Understanding vector biology is essential in this endeavor. Our goal was to document differences in probing behavior linked to sex. Based on both a literature review and our results, we conclude that there is either no effect of sex or that identifying such an effect requires a sample size at least four times larger than standard methodologies. Including both color and sex in statistical models did not improve model performance. Both sex and color are correlated with body size, and body size has not been considered in previous studies on sex in D. citri in terms of probing behavior. An effect of body size was found wherein larger psyllids took longer to reach ingestion behaviors and larger individuals spent more time-ingesting phloem, but these relationships explained little of the variability in these data. We suggest that the effects of sex can be ignored when running EPG experiments on healthy psyllids.

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