| estimation of the number of aphids carrying citrus tristeza virus that visit adult citrus trees. | aphid species were counted on citrus trees in orchards in valencia, spain, in the spring and autumn of 1997, 1998 and 1999. moericke yellow water traps, the 'sticky shoot' method and counts of established colonies were used in extensive surveys in which 29,502 aphids were recorded and identified. aphis spiraecola and aphis gossypii were the most abundant aphid species. the numbers of aphid species landing on mature trees of grapefruit, sweet orange, lemon and clementine and satsuma mandarins, we ... | 2004 | 15036840 |
| survey methods for assessment of citrus tristeza virus incidence when toxoptera citricida is the predominant vector. | abstract citrus tristeza virus (ctv) incidence may be assessed by sampling groups of citrus trees, recording the groups as ctv positive (one or more infected trees) or ctv negative (no infected trees), and then calculating disease incidence at the scale of the individual tree by means of a formula involving incidence at the group scale and the number of trees per group. this procedure works well when the ctv status of a tree can be regarded as independent of the ctv status of other trees in the ... | 1999 | 18944721 |
| incidence and epidemiology of citrus tristeza virus in the valencian community of spain. | the first outbreak of citrus tristeza disease in spain caused by citrus tristeza virus (ctv) was recorded in 1957 in the valencian community (vc). in total c. 40 million trees, mainly of sweet orange and mandarin grafted on sour orange rootstocks, declined due to ctv. large-scale surveys in different municipalities of the vc indicated that the disease spread very fast. incidence increased from 11% in 1989 to 53% in 1998. toxoptera aurantii and aphis spiraecola (inefficient aphid vectors of ctv) ... | 2000 | 11137164 |
| nucleotide sequence of the coat protein gene of citrus tristeza virus: comparison of biologically diverse isolates collected in israel. | the sequences of the coat protein genes of four seedling yellows (sy) and four non-sy (nsy) of citrus tristeza virus (ctv) isolates, which were collected in israel over a period of 30 years, were analyzed. pairwise comparisons showed extensive similarities in the nucleotide and amino acid sequences of six isolates designated the vt group. this group consists of three nsy isolates that cause a very mild ctv reaction on the sensitive combination of sweet orange (swo) grafted on sour orange (so), a ... | 1993 | 8279125 |
| examination of the effect of aphid vector population composition on the spatial dynamics of citrus tristeza virus spread by stochastic modeling. | abstract aphid vector species population composition is known to affect the spatial patterns of citrus tristeza virus (ctv) and the changes in these patterns over time. however, the biological processes that are associated with virus spread have not been well defined. the spatiotemporal dynamics of ctv were examined using data collected from research plots in the dominican republic and costa rica, where the brown citrus aphid (bca), toxoptera citricida, was the predominant species, and in florid ... | 1999 | 18944697 |
| aphid transmission alters the genomic and defective rna populations of citrus tristeza virus isolates. | abstract a total of 14 spanish isolates of citrus tristeza virus (ctv) and 1 isolate from japan were transmitted by aphis gossypii, and the subisolates obtained were compared with the source isolates for symptom expression and double-stranded rna (dsrna) pattern. of the 14 spanish isolates, 9 showed altered dsrna patterns after aphid transmission but only minor variations in the intensity of symptoms induced on mexican lime. northern blot hybridization with complementary dna (cdna) probes corres ... | 2000 | 18944601 |
| quantitative detection of citrus tristeza virus in citrus and aphids by real-time reverse transcription-pcr (taqman). | a quantitative and multiplex real-time rt-pcr assay was developed to detect citrus tristeza virus (ctv) along with plant mrna, which serves as an internal control to ascertain rna extraction quality. the real-time technique was validated against 39 ctv strains from around the world as well as with the aphid vector, aphis gossypii, given a 48 h acquisition access period on a ctv source plant. the assay was effective for quantitation of the viral template in infected plants and in single aphids. c ... | 2008 | 17888522 |
| spatial and temporal spread of citrus tristeza virus and its aphid vectors in the north western area of morocco. | first report of citrus tristeza virus (ctv,closterovirus) in morocco datesback to 1961 in collections of citrus varieties. an exhaustive survey of citrus in the north of the country in 2009 revealed that ctv was spread all over the citrus production area. we attempted to evaluate the relative contribution of different aphid species in the spread of ctv disease in a citrus reticulata orchard at the loukkous region during 2 years (2012 and 2013). the overall ctv incidence estimated in the experime ... | 2016 | 25884375 |