scholarly journals Incidence of Citrus Tristeza Virus and its Vector Toxoptera citricida in Different Parts of Assam and Nagaland, India

2021 ◽  
Vol 10 (9) ◽  
pp. 68-78
Author(s):  
Maongkar T. Changkiri Pulin Patgiri ◽  
Palash Deb Nath Rokozeno ◽  
Otto S. Awomi
Keyword(s):  
Citrus Tristeza Virus ◽  
Field Survey ◽  
Disease Incidence ◽  
Citrus Limon ◽  
Toxoptera Citricida ◽  
Aphid Vectors ◽  
Tristeza Virus ◽  
Das Elisa ◽  
Different Parts ◽  
Citrus Tristeza

A field survey was conducted in 2018 to study the incidence of citrus tristeza virus (CTV) and its aphid vectors, in different citrus growing regions of the states of Assam and Nagaland, India. Leaf samples of Assam lemon (Citrus limon) and Khasi mandarin (Citrus reticulata) were collected from four districts of Assam (Jorhat, Tinsukia, Sivasagar and Golaghat) and two districts of Nagaland (Mokokchung and Wokha). Citrus leaf samples were collected from a total of 190 citrus plants and were used for detection of CTV infection through Double Antibody Sandwich-Enzyme linked Immuno-Sorbent Assay (DAS-ELISA). According to the results, 75 per cent CTV disease incidence was detected in surveyed areas of Assam and 24.55 per cent CTV disease incidence was detected in surveyed areas of Nagaland. District wise, the highest CTV disease incidence (96.67 %) was detected in Tinsukia district of Assam and the lowest (21.43 %) was detected in Mokokchung district of Nagaland. Aphid samples were also collected during the survey and the presence of the vector Toxoptera citricida, in all the locations was determined.

scholarly journals First Report from Syria of Citrus tristeza virus in Citrus spp.

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1468-1468
Author(s):  
R. Abou Kubaa ◽  
K. Djelouah ◽  
A. M. D'Onghia ◽  
R. Addante ◽  
M. Jamal
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Citrus Limon ◽  
Potential Threat ◽  
First Report ◽  
Mexican Lime ◽  
Vein Clearing ◽  
Citrus Varieties ◽  
Tristeza Virus ◽  
Citrus Tristeza

During the spring of 2006, the main Syrian citrus-growing areas of Lattakia (Jableh, Aledyye, Eseelya, Siano, and Hresoon provinces) and Tartous (Almintar, Aljammase, Karto, Majdaloonelbahr, Yahmour, Amreet, Althawra, and Safita provinces) were surveyed to assess the presence of Citrus tristeza virus (CTV). Eight nurseries (approximately 130 plants per nursery), two budwood source fields (approximately 230 trees per field), and 19 groves (approximately 60 trees per grove) containing the main citrus varieties were visually inspected and sampled for serological assays. The hierarchical sampling method was carried out in each selected grove (2). Infected samples were collected from two nurseries, two budwood source fields, and six groves. Stems and leaf petioles from nursery trees and flower explants from the groves were collected and analyzed for CTV by direct tissue blot immunoassay (DTBIA) with the commercial kit from Plantprint (Valencia, Spain). Of 2,653 samples tested, 89 (4%) CTV-infected plants were detected. Five citrus varieties were found to be infected and Meyer lemon (Citrus limon ‘Meyer’) had the highest incidence at 16%. Numerous sweet orange varieties (Citrus sinensis L.) were found to be highly infected in the field, but only the Washington navel sweet orange was found to be infected in the nurseries. No clear CTV symptoms were observed during the survey. Samples that were positive for CTV by DTBIA were also positive by biological indexing on Mexican lime (C. aurantifolia) and immunocapture-reverse transcription-PCR as described by Nolasco et al. (3). Coat protein gene sequences obtained from five selected clones of a Syrian CTV isolate (GenBank Accession No. EU626555) showed more than 99 and 98% nucleotide sequence identity to a Jordanian CTV isolate (GenBank Accession No. AY550252) and the VT isolate (GenBank Accession No. U56902), respectively. Almost all infected samples induced moderate vein clearing symptoms when grafted to Mexican lime. Symptoms of vein clearing, leaf cupping, stunting, and stem pitting on Mexican lime were induced by graft transmission of CTV from one Valencia sample from the Tartous area. The viral inoculum is widely and randomly distributed in commercial groves, especially in the southern Tartous area and in some nurseries. To our knowledge, this is the first report of CTV in Syria. However, CTV was reported from the neighboring citrus-growing countries of Lebanon, Turkey, and Jordan (1), and the severe seedling yellows strain is present in this area, which poses a potential threat to Syrian citriculture. References: (1) G. H. Anfoka et al. Phytopathol. Mediterr. 44:17, 2005. (2) G. Hughes and T. R. Gottwald, Phytopathology 88:715, 1998. (3) G. Nolasco et al. Eur. J. Plant Pathol. 108:293, 2002.

scholarly journals Breakdown of Cross-Protection of Grapefruit from Decline-Inducing Isolates of Citrus tristeza virus Following Introduction of the Brown Citrus Aphid

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1116-1118 ◽  
Author(s):  
C. A. Powell ◽  
R. R. Pelosi ◽  
P. A. Rundell ◽  
M. Cohen
Keyword(s):  
Immunosorbent Assay ◽  
Citrus Tristeza Virus ◽  
Cross Protection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Experimental Area ◽  
Toxoptera Citricida ◽  
The Cross ◽  
Tristeza Virus ◽  
Citrus Tristeza

A 21-year-old replicated field planting of 84 ‘Ruby Red’ grapefruit trees cross-protected with three mild isolates of Citrus tristeza virus (CTV) was assessed for decline-inducing and non-decline-inducing isolates of the virus 5 years after the brown citrus aphid (BrCA) (Toxoptera citricida Kirkaldy) first was established in the experimental area. Prior to the introduction of the BrCA, the cross-protecting mild isolates had significantly reduced detectable infection with decline-inducing isolates of CTV for 16 years (average infection of 13% in cross-protected trees compared with 67% in unprotected trees). After the introduction of the BrCA, infections with decline-inducing CTV (measured by enzyme-linked immunosorbent assay) were 57, 81, and 71% for trees protected with three mild isolates, respectively, compared with 95% in unprotected trees. These results suggest that the introduction of BrCA accelerated the breakdown of cross-protection against decline-inducing isolates of CTV in grapefruit.

LARGE SCALE SURVEY OF CITRUS TRISTEZA VIRUS (CTV) AND ITS APHID VECTORS IN MOROCCO

2015 ◽  
pp. 753-757
Author(s):  
Mohamed Afechtal ◽  
Khaled Djelouah ◽  
Giuseppe Cocuzza ◽  
Anna M. D'Onghia
Keyword(s):  
Large Scale ◽  
Citrus Tristeza Virus ◽  
Aphid Vectors ◽  
Large Scale Survey ◽  
Tristeza Virus ◽  
Citrus Tristeza

scholarly journals Increase and Patterns of Spread of Citrus Tristeza Virus Infections in Costa Rica and the Dominican Republic in the Presence of the Brown Citrus Aphid, Toxoptera citricida

1998 ◽  
Vol 88 (7) ◽  
pp. 621-636 ◽  
Author(s):  
T. R. Gottwald ◽  
S. M. Garnsey ◽  
J. Borbón
Keyword(s):  
Costa Rica ◽  
Dominican Republic ◽  
Spatial Autocorrelation ◽  
Citrus Tristeza Virus ◽  
Local Area ◽  
Enzyme Linked Immunosorbent Assay ◽  
Toxoptera Citricida ◽  
Area Of Influence ◽  
Tristeza Virus ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) was monitored for 4 years by monoclonal antibody probes via enzyme-linked immunosorbent assay in four citrus orchards in northern Costa Rica and four orchards in the Dominican Republic following the introduction of the brown citrus aphid, Toxoptera citricida. The Gompertz nonlinear model was selected as the most appropriate in most cases to describe temporal increase of CTV. Ordinary runs analysis for association of CTV-positive trees failed to show a spatial relationship of virus status among immediately adjacent trees within or across rows. The beta-binomial index of dispersion for various quadrat sizes suggested aggregations of CTV-positive trees for all plots within the quadrat sizes tested. Spatial autocorrelation analysis of proximity patterns suggested that aggregation often existed among quadrats of various sizes up to four lag distances; however, significant lag positions discontinuous from the main proximity pattern were rare. Some asymmetry was also detected for some spatial autocorrelation proximity patterns. These results were interpreted to mean that, although CTV-positive trees did not often influence immediately adjacent trees, virus transmission was common within a local area of influence that extended two to eight trees in all directions. Where asymmetry was indicated, this area of influence was somewhat elliptical. The spatial and temporal analyses gave some insight into possible underlying processes of CTV spread in the presence of T. citricida and suggested CTV spread was predominantly to trees within a local area. Patterns of longer-distance spread were not detected within the confines of the plot sizes tested. Longer-distance spread probably exists, but may well be of a complexity beyond the detection ability of the spatial analysis methods employed, or perhaps is on a scale larger than the dimensions of the plots studied.

Spatial and temporal spread of Citrus tristeza virus and its aphid vectors in the North western area of Morocco

2015 ◽  
Vol 23 (6) ◽  
pp. 903-912 ◽  
Author(s):  
Abdesslam Elhaddad ◽  
Amal ElAmrani ◽  
Alberto Fereres ◽  
Aranzazu Moreno
Keyword(s):  
Citrus Tristeza Virus ◽  
The North ◽  
Western Area ◽  
Aphid Vectors ◽  
Tristeza Virus ◽  
North Western ◽  
Temporal Spread ◽  
Citrus Tristeza

scholarly journals Separation of Citrus Tristeza Virus Isolates in Mixed Infections through Transfer by Single Brown Citrus Aphids

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 694-696 ◽  
Author(s):  
Charles A. Powell ◽  
Youjian Lin
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Mixed Infections ◽  
Citrus Paradisi ◽  
Inoculum Sources ◽  
Toxoptera Citricida ◽  
Orange Trees ◽  
Tristeza Virus ◽  
Virus Isolates ◽  
Citrus Tristeza

One hundred single brown citrus aphid (BCA) (Toxoptera citricida Kirkaldy) transmission attempts were made from each of 16 different citrus trees [8 grapefruit (Citrus paradisi Macf.) and 8 sweet orange (C. sinensis (L.) Osbeck)] previously inoculated with decline-inducing (T36-CTV), non-decline-inducing (T30-CTV), a mixture of the two Citrus tristeza virus isolate types, or no CTV. Successful CTV transmission occurred in 1.5% of attempts from grapefruit trees that had been bark-chip-inoculated with T36-CTV, 3% of attempts from orange trees inoculated with T36-CTV, 3% of attempts from grapefruit trees inoculated with both T36- and T30-CTV, 4% of attempts from orange trees inoculated with both T36- and T30-CTV, 1.5% of attempts from grapefruit trees inoculated with T30-CTV, and 3.5% of attempts from orange trees inoculated with T30-CTV. Single BCA were able to recover T30-like-CTV from trees believed to be inoculated only with T36-CTV, and T36-like-CTV from trees believed to be inoculated only with T30-CTV, suggesting that these inoculum sources were also mixtures of T36-CTV and T30-CTV. The T36-CTV was not immunologically detectable in some of the trees from which it was transmitted indicating that single BrCA can recover T36-CTV from a T36-CTV/T30-CTV mixture in which the T36-CTV is an undetectable, minority component.

scholarly journals Titer Variation of Citrus Tristeza Virus in Aphids at Different Acquisition Access Periods and Its Association with Transmission Efficiency

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 874-879
Author(s):  
Jinxiang Liu ◽  
Lingdi Li ◽  
Hengyan Zhao ◽  
Yan Zhou ◽  
Hongsu Wang ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Transmission Rate ◽  
Virus Titer ◽  
Transmission Efficiency ◽  
Pcr Assay ◽  
Toxoptera Citricida ◽  
The Mean ◽  
Green Fluorescent ◽  
Tristeza Virus ◽  
Citrus Tristeza

Tristeza, caused by citrus tristeza virus (CTV; Closterovirus, Closteroviridae), is of significant economic importance. Tristeza epidemics have caused severe declines in productivity, and even death, of millions of citrus trees on sour orange rootstock in many regions all over the world. In the field, CTV is most efficiently vectored by the brown citrus aphid (Toxoptera citricida (Kirkaldy)) in a semipersistent manner. The transmission efficiency of the vector is influenced by its acquisition access period (AAP) for CTV. A real-time RT-PCR assay using SYBR Green fluorescent dye was used to estimate the CTV titers in groups of 15 aphids under AAPs after 0.5 to 48 h for three CTV isolates (CT11A, CT16-2, and CTLJ). Similar trends for CTV titer in viruliferous aphids were displayed for the three isolates. The maximum CTV titer was at AAP 6 h for isolates CT11A and CT16-2, and at 4 h for isolate CTLJ. During the AAPs from 0.5 to 6 h, the mean CTV titer of CT16-2 increased from 7.8 × 104 to 1.71 × 107 copies per 15 aphids, and was correlated with an increase in transmission rate from 20 to 90.9%. This suggests that the transmission efficiency is positively correlated with viral titer in the insect from 0.5 h until 6 h AAPs. While a downward trend in CTV titer was observed after a 6-h AAP, the transmission rate remained higher than 90% up to 48 h. These results indicate that factors other than the virus titer in the vector contribute to successful transmission under long acquisition conditions. This is the first detailed quantitative analysis of CTV in its main vector species following different AAPs and its association with transmission efficiency, and should enhance our understanding of T. citricida-CTV interactions.

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