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.

scholarly journals Probing behavior of Diaphorina citri (Hemiptera: Liviidae) on Valencia orange influenced by sex, color, and size

2019 ◽  
Author(s):  
Timothy A Ebert ◽  
Michael E Rogers
Keyword(s):  
Body Size ◽  
Statistical Models ◽  
Model Performance ◽  
Diaphorina Citri ◽  
Probing Behavior ◽  
Valencia Orange ◽  
Improve Model ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Improve Model Performance

ABSTRACTCandidatus Liberibacter asiaticus is vectored by the psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) 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. 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.

scholarly journals Latency and Persistence of ‘Candidatus Liberibacter asiaticus’ in Its Psyllid Vector, Diaphorina citri (Hemiptera: Liviidae)

2017 ◽  
Vol 107 (3) ◽  
pp. 264-272 ◽  
Author(s):  
Maria Cristina Canale ◽  
Arthur Fernando Tomaseto ◽  
Marineia de Lara Haddad ◽  
Helvécio Della Coletta-Filho ◽  
João Roberto Spotti Lopes
Keyword(s):  
Latent Period ◽  
Acquisition Time ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Old Adults ◽  
Sequential Inoculation ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Series Of Experiments

Although ‘Candidatus Liberibacter asiaticus’ (Las) is a major pathogen associated with citrus huanglongbing (HLB), some characteristics of transmission by the psyllid vector Diaphorina citri are not fully understood. We examined the latent period and persistence of transmission of Las by D. citri in a series of experiments at 25°C, in which third-instar psyllid nymphs and 1-week-old adults were confined on infected citrus for an acquisition access period (AAP), and submitted to sequential inoculation access periods (IAPs) on healthy citrus seedlings. The median latent period (LP50, i.e., acquisition time after which 50% of the individuals can inoculate) of 16.8 and 17.8 days for psyllids that acquired Las as nymphs and adults, respectively, was determined by transferring single individuals in 48-h IAPs. Inoculation events were intermittent and randomly distributed over the IAPs, but were more frequent after acquisition by nymphs. A minimum latent period of 7 to 10 days was observed by transferring groups of 10 psyllids in 48-h IAPs, after a 96-h AAP by nymphs. Psyllids transmitted for up to 5 weeks, when submitted to sequential 1-week IAPs after a 14-day AAP as nymphs. The long latent period and persistence of transmission are indirect evidences of circulative propagation of Las in D. citri.

scholarly journals Development on Infected Citrus over Generations Increases Vector Infection by ‘Candidatus Liberibacter Asiaticus in Diaphorina citri’

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 469
Author(s):  
Inaiara de Souza Pacheco ◽  
Diogo Manzano Galdeano ◽  
João Roberto Spotti Lopes ◽  
Marcos Antonio Machado
Keyword(s):  
Management Strategies ◽  
Fourth Generation ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Citrus Orchards ◽  
Vector Efficiency ◽  
Control And Eradication

‘Candidatus Liberibacter asiaticus’ (CLas) is a major causal agent of citrus Huanglongbing (HLB), which is transmitted by Asian citrus psyllid (ACP), Diaphorina citri, causing severe losses in various regions of the world. Vector efficiency is higher when acquisition occurs by ACP immature stages and over longer feeding periods. In this context, our goal was to evaluate the progression of CLas population and infection rate over four ACP generations that continuously developed on infected citrus plants. We showed that the frequency of CLas-positive adult samples increased from 42% in the parental generation to 100% in the fourth generation developing on CLas-infected citrus. The bacterial population in the vector also increased over generations. This information reinforces the importance of HLB management strategies, such as vector control and eradication of diseased citrus trees, to avoid the development of CLas-infected ACP generations with higher bacterial loads and, likely, a higher probability of spreading the pathogen in citrus orchards.

scholarly journals Murraya paniculata and Swinglea glutinosa as Short-Term Transient Hosts of ‘Candidatus Liberibacter asiaticus’ and Implications for the Spread of Huanglongbing

2019 ◽  
Vol 109 (12) ◽  
pp. 2064-2073 ◽  
Author(s):  
Juan Camilo Cifuentes-Arenas ◽  
George Andrew Charles Beattie ◽  
Leandro Peña ◽  
Silvio Aparecido Lopes
Keyword(s):  
Sweet Orange ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Principal Vector ◽  
Dead End ◽  
Valencia Orange ◽  
Murraya Paniculata ◽  
Citrus Rootstock ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Murraya paniculata and Swinglea glutinosa are aurantioid hosts of the Asian citrus psyllid (ACP) Diaphorina citri, the principal vector of ‘Candidatus Liberibacter asiaticus’ (Las). Las is the pathogen associated with huanglongbing (HLB), the Asian form of which is the most devastating disease of Citrus species and cultivars (Rutaceae: Aurantioideae). M. paniculata is a common ornamental and S. glutinosa is grown as an ornamental, a citrus rootstock, and a hedgerow fence plant. Because of the uncertain status of these plants as reservoirs of Las, a series of cross-inoculation bioassays were carried out in different environments, using infected Valencia sweet orange (Citrus × aurantium) infected shoot tops as a source of inoculum and D. citri nymphs and adults reared on M. paniculata and S. glutinosa to inoculate pathogen-free Valencia orange plantlets. In contrast to sweet orange, Las was more unevenly distributed and reached much lower titers in M. paniculata and S. glutinosa. Infections in M. paniculata and S. glutinosa were also transient. Very few insects that successfully acquired Las from M. paniculata and S. glutinosa were able to transmit the pathogen to healthy citrus. Transmission rates were low from M. paniculata (1.0%) and S. glutinosa (2.0%) and occurred only in a controlled environment highly favorable to Las and ACP using 10-day-old adults that completed their life cycle on Las-positive plants. Our study showed that in HLB-endemic areas, M. paniculata and S. glutinosa can be deemed as epidemiologically dead-end hosts for Las and are not important alternative hosts of the pathogen for transmission to citrus. However, under a combination of conditions highly favorable to Las infection and transmission and in the absence of effective quarantine procedures, these plants could eventually serve as carriers of Las to regions currently free from HLB.

Prevalent transmission of 'Candidatus Liberibacter asiaticus’ over ‘Ca. Liberibacter americanus’ in a long-term controlled environment

2021 ◽  
Author(s):  
Maria Cândida de Godoy Gasparoto ◽  
Isabela Vescove Primiano ◽  
Renato Bassanezi ◽  
Silvia Afonseca Lourenço ◽  
Luiz Montesino ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Citrus Orchards ◽  
Test Plants

In Brazil, citrus huanglongbing (HLB) is associated with ‘Candidatus Liberibacter americanus’ (CLam) and ‘Ca. Liberibacter asiaticus’ (CLas). However, there are few studies about HLB epidemiology when both Liberibacter spp. and its insect vector, the Asian citrus psyllid (ACP, Diaphorina citri), are present. The objective of this work was to compare the transmission of HLB by ACP when both CLam and CLas are present as primary inoculum. Two experiments were performed under screenhouse conditions from April 2008 to January 2012 (experiment 1) and from February 2011 to December 2015 (experiment 2). The experiments were carried out with sweet orange plants infected with CLam or CLas as inoculum source surrounded by sweet orange healthy plants. One hundred Liberibacter-free adult psyllids were monthly confined to the source of inoculum plants for 7 days with subsequent free movement inside the screenhouse. Fortnightly, nymphs and adults of psyllids were monitored. Psyllid and leaf samples were collected periodically for Liberibacter detection by PCR or qPCR. CLas was detected more frequently than CLam in both psyllid and leaf samples. No mixed infections were detected in the psyllids. A clear prevalence of CLas over CLam was observed in both experiments. The final HLB incidences were 16.7 and 14.5% of Liberibacter-positive test plants, and CLas was detected in 92.3 and 93.1% of these infected plants. Mixed infection was observed only in 3.8% of infected test plants in experiment 1. These results endorse the shift in the prevalence of CLam to CLas observed in citrus orchards of São Paulo, Brazil.

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 Detection of ‘Candidatus Liberibacter asiaticus’ in Diaphorina citri and Its Importance in the Management of Citrus Huanglongbing in Florida

2008 ◽  
Vol 98 (4) ◽  
pp. 387-396 ◽  
Author(s):  
K. L. Manjunath ◽  
S. E. Halbert ◽  
C. Ramadugu ◽  
S. Webb ◽  
R. F. Lee
Keyword(s):  
Quantitative Polymerase Chain Reaction ◽  
Diagnostic Methods ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Production ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Polymerase Chain ◽  
Polymerase Chain Reaction Methodology

Citrus huanglongbing (HLB or citrus greening), is a highly destructive disease that has been spreading in both Florida and Brazil. Its psyllid vector, Diaphorina citri Kuwayama, has spread to Texas and Mexico, thus threatening the future of citrus production elsewhere in mainland North America. Even though sensitive diagnostic methods have been developed for detection of the causal organisms, Candidatus Liberibacter spp., the pathogen cannot be detected consistently in plants until symptoms develop, presumably because of low titer and uneven distribution of the causal bacteria in nonsymptomatic tissues. In the present study, TaqMan based real-time quantitative polymerase chain reaction methodology was developed for detection of ‘Ca. L. asiaticus’ in D. citri. Over 1,200 samples of psyllid adults and nymphs, collected from various locations in Florida, from visually healthy and HLB symptomatic trees at different times of the year were analyzed to monitor the incidence and spread of HLB. The results showed that spread of ‘Ca. L. asiaticus’ in an area may be detected one to several years before the development of HLB symptoms in plants. The study suggests that discount garden centers and retail nurseries may have played a significant role in the widespread distribution of psyllids and plants carrying HLB pathogens in Florida.

scholarly journals Resolution of the Identity of ‘Candidatus Liberibacter’ Species From Huanglongbing-Affected Citrus in East Africa

Plant Disease ◽  
2017 ◽  
Vol 101 (8) ◽  
pp. 1481-1488 ◽  
Author(s):  
Ronel Roberts ◽  
Glynnis Cook ◽  
Tim G. Grout ◽  
Fathiya Khamis ◽  
Ivan Rwomushana ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Housekeeping Genes ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Production ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Resolution Of The Identity

‘Candidatus Liberibacter asiaticus’, the bacterium associated with citrus Huanglongbing (HLB), was reported from Uganda and tentatively from Tanzania, posing a threat to citriculture in Africa. Two surveys of citrus expressing typical HLB symptoms were conducted in Uganda, Kenya, and Tanzania to verify reports of ‘Ca. L. asiaticus’ and to assess the overall threat of HLB to eastern and southern African citrus production. Samples were analyzed for the presence of ‘Candidatus Liberibacter’ species by real-time PCR and partial sequencing of three housekeeping genes, 16S rDNA, rplJ, and omp. ‘Ca. L. africanus’, the bacterium historically associated with HLB symptoms in Africa, was detected in several samples. However, samples positive in real-time PCR for ‘Ca. L. asiaticus’ were shown not to contain ‘Ca. L. asiaticus’ by sequencing. Sequences obtained from these samples were analogous to ‘Ca. L. africanus subsp. clausenae’, identified from an indigenous Rutaceae species in South Africa, and not to ‘Ca. L. asiaticus’. Results indicate a nontarget amplification of the real-time assay and suggest that previous reports of ‘Ca. L. asiaticus’ from Uganda and Tanzania may be mis-identifications of ‘Ca. L. africanus subsp. clausenae’. This subspecies was additionally detected in individual Diaphorina citri and Trioza erytreae specimens recovered from collection sites. This is the first report of ‘Ca. L. africanus subsp. clausenae’ infecting citrus and being associated with HLB symptoms in this host.

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