Coffee Ringspot Virus Research Articles

Infection by coffee ringspot virus is identified for the first time in succulent plants

Infection by coffee ringspot virus is identified for the first time in succulent plants

Coffee ringspot virus (coffee ringspot)

Coffee ringspot virus (coffee ringspot)

HISTOPATHOLOGICAL PATTERNS OF LESIONS CAUSED BY TWO DICHORHAVIRUS

Different from most plant viruses, Brevipalpus mite-transmitted viruses (BTV) cause localized infection, not being able to systemically invade the infected plant. To broaden the specter of the histopathological changes in leaf tissues induced by BTV infection, we examined the tissue organization of leaf lesions caused by the infection of two additional representatives of dichorhaviruses, Clerodendrum chlorotic spot virus (ClCSV) and Coffee ringspot virus (CoRSV). In general, tissue alterations within the lesions followed the pattern noticed in CiLV-C and CiLV-N infection. In all analyzed lesions, necrotic cells form the central region that is surrounded by a chlorotic halo where hypertrophied cells commonly occur. Presence of reactive oxygen components were also a characteristic of the chlorotic halo. Though more cases of localized lesions on leaves infected by more BTV, remains to be analyzed, it seems that these lesions respond similarly upon infection by BTV, either Cile- or Dichorhavirus.

Effect of water stress and Coffee ringspot virus on coffee leaf temperature and its relationship with Brevipalpus yothersi population

Effect of water stress and Coffee ringspot virus on coffee leaf temperature and its relationship with Brevipalpus yothersi population

First Report of Citrus Chlorotic Spot Virus Infecting the Succulent Plant Agave desmettiana

Endemic in the Americas, citrus leprosis is a viral disease that reduces yields and threatens the sustainability of citrus orchards. The disease is caused by a heterogeneous group of ssRNA viruses assigned to the genera Dichorhavirus (family Rhabdoviridae, order Mononegavirales) or Cilevirus (unassigned genus) (Freitas-Astua et al. 2018). The typical dichorhavirus genome encompasses two (–)ssRNA molecules that encode six open reading frames (ORFs) (Dietzgen et al. 2018). Isolates of the dichorhavirus citrus chlorotic spot virus (CiCSV) were previously identified in Teresina, Piaui, Brazil (Chabi-Jesus et al. 2018). Besides affecting sweet orange (Citrus sinensis) trees producing symptoms resembling early lesions of a typical citrus leprosis, CiCSV also infects beach hibiscus (Talipariti tiliaceum syn. Hibiscus tiliaceus L.) plants. In 2018, a dozen of the ornamental Agave desmettiana Jacob plants (Agavaceae) showing chlorotic lesions were detected in the urban region of Teresina city within an area of approximately 30 km², including the region where the original CiCSV-infected plants were described. Analyses of symptomatic agaves’ tissues by transmission electron microscopy revealed the presence of viroplasms in the nucleus of the infected parenchymal cells, as a typical dichorhavirus infection (Dietzgen et al. 2018). Moreover, eight mites that were collected during the examination of the symptomatic leaves were morphologically identified as Brevipalpus aff. yothersi, the same species found in CiCSV-infected citrus (Chabi-Jesus et al. 2018). Total RNA from leaf lesions of three symptomatic agave plants (isolates Trs4, Trs5, and Trs6) was extracted using TRIzol reagent (Life Technologies, Foster City, CA), and the reverse transcription polymerase chain reaction assays performed using all of the primer pairs available for the detection of known dichorhaviruses (Dietzgen et al. 2018) proved the presence of CiCSV. Additionally, the same RNA extracts reacted with a digoxigenin-labeled probe derived from the N gene of CiCSV_Trs1 in an RNA dot-blot assay (Roche Diagnostics, Mannheim, Germany). Ninety-five percent of the isolate Trs4’s genome was recovered after the Sanger sequencing of the overlapping amplicons generated by using 15 primers pairs (Chabi-Jesus et al. 2018). Globally, RNA1 (6,082 nt, GB: MH595621) and RNA2 (5,688 nt, MH595622) shows 96.4% nucleotide sequence identity with the type virus CiCSV_Trs1 (KY700685 and KY700686) and less than 75% nucleotide sequence identity with the dichorhaviruses orchid fleck virus (OFV; AB244417 and AB244418), coffee ringspot virus (CoRSV; KF812525 and KF812526), citrus leprosis virus N (CiLV-N; KX982176 and KX982179), and clerodendrum chlorotic spot virus (ClCSV; MG938506 and MG938507). Comparisons of the deduced amino acid sequences of the putative proteins N, P, MP, M, G, and L (encoded by ORFs 1 to 6, respectively) of CiCSV_Trs4 show 95 to 99% identity with CiCSV_Trs1 and 28 to 90% identity with OFV, CoRSV, CiLV-N, and ClCSV. Sequences of the generated amplicons corresponding to G and L genes from the isolates Trs5 and Trs6 (MH802037, MH802038, MH802039, and MH802040, respectively) showed >93% nucleotide sequence identity with CiCSV_Trs1 (KY700685 and KY700686) and with isolate Trs4. Comprehensively, results indicate that CiCSV_Trs4, -5, and -6 are isolates of the species Citrus chlorotic spot dichorhavirus of the genus Dichorhavirus, whose transmission has been previously associated with the mite B. aff. yothersi. This is the first report of CiCSV naturally infecting the succulent plant A. desmettiana, and, to our knowledge, it is also the first report of a (–)ssRNA virus infecting plants of this genus.

Good to the last drop: The emergence of coffee ringspot virus.

Two and a half billion times per day a human hand reaches for a fresh cup of coffee. Although arguably dispensable for life per se, with an industry value of US$174 billion, coffee provides the lifeblood that sustains economies of producing countries located in the “coffee belt” situated between the Tropics of Cancer and Capricorn. As a “solvent” in which many human interactions take place, coffee is witness to the broad spectrum of human activities from the mundane to the pleasurable and personal. However, in opposition to its economic, cultural, and physiological importance, diseases such as coffee rust (caused by the fungus Hemileia vastatrix) dictate activity on stock markets with their periodic epidemics, which in turn affects the migration patterns of displaced farm workers [1]. Other diseases, such as those caused by coffee ringspot virus (CoRSV), currently fly mostly under the radar of many integrated pest management systems. The unique biology of this and related viruses offers exciting research opportunities ranging from cell biology, plant pathology and physiology, conservation ecology, to climate change-related epidemiology. This review highlights important aspects of CoRSV, including its unique features, and examines the potential role of climate change in its emergence (Fig 1). Open in a separate window Fig 1 Diverse array of research projects related to understanding the effect of CoRSV on coffee. (A) Whether enjoyed alone or in the company of others, coffee is an integral component of daily life in all countries around the world. Only one small-scale study has been done to determine the effect of CoRSV on coffee quality [34]. (B) The effect of CoRSV on the yield of coffee plants has not been examined. (C) No formal investigations have been made to determine how CoRSV influences the development of coffee cherries. (D) Only one study has investigated the population structure of CoRSV [8, 35]. It remains to be determined if phylogenetic trees derived from different CoRSV genes or from viral RNA isolated from plants or mites are congruent. Furthermore, evidence for recombination or reassortment of CoRSV genomes has not been investigated in detail. (E) The reservoir of CoRSV in wild species, particularly in the Cerrado of Brazil, has not been investigated. It is unknown if the population structure of CoRSV in the wild is similar to that in coffee plants. (F) The molecular basis for temperature dependent susceptibility to systemic infections has not been determined [23]. (G) The cell biology of CoRSV beyond generation of protein interaction and localization maps is poorly characterized, particularly with respect to identification of host factors required for replication and cell-to-cell movement, viroplasm formation, and nucleocytoplasmic trafficking of CoRSV nucleocapsids and proteins [23]. CoRSV, coffee ringspot virus; NPC, nuclear pore complex; VP, viroplasm; XPO1, Exportin 1.

Identification and Characterization of Citrus Chlorotic Spot Virus, a New Dichorhavirus Associated with Citrus Leprosis-Like Symptoms.

Local chlorotic spots resembling early lesions characteristic of citrus leprosis (CL) were observed in leaves of two sweet orange (Citrus sinensis L.) trees in Teresina, State of Piauí, Brazil, in early 2017. However, despite the similarities, these spots were generally larger than those of a typical CL and showed rare or no necrosis symptoms. In symptomatic tissues, transmission electron microscopy revealed the presence of viroplasms in the nuclei of the infected parenchymal cells and rod-shaped particles with an average size of approximately 40 × 100 nm, resembling those typically observed during infection by dichorhaviruses. A bipartite genome of the putative novel virus, tentatively named citrus chlorotic spot virus (CiCSV) (RNA1 = 6,518 nucleotides [nt] and RNA2 = 5,987 nt), revealed the highest nucleotide sequence identity values with the dichorhaviruses coffee ringspot virus strain Lavras (73.8%), citrus leprosis virus N strain Ibi1 (58.6%), and orchid fleck virus strain So (56.9%). In addition to citrus, CiCSV was also found in local chlorotic lesions on leaves of the ornamental plant beach hibiscus (Talipariti tiliaceum (L.) Fryxell). Morphological characterization of mites recovered from the infected plants revealed at least two different types of Brevipalpus. One of them corresponds to Brevipalpus yothersi. The other is slightly different from B. yothersi mites but comprises traits that possibly place it as another species. A mix of the two mite types collected on beach hibiscus successfully transmitted CiCSV to arabidopsis plants but additional work is required to verify whether both types of flat mite may act as viral vectors. The current study reveals a newly described dichorhavirus associated with a citrus disease in the northeastern region of Brazil.

First Report of Brevipalpus papayensis as Vector of Coffee ringspot virus and Citrus leprosis virus C

Coffee ringspot virus (CoRSV) and Citrus leprosis virus C (CiLV-C) are two emergent pathogens that can cause significant losses to coffee and citrus, respectively. Recently, it was verified that Brevipalpus phoenicis, originally reported as vector of these viruses, is indeed a complex group reclassified into eight mite species (Beard et al. 2015). Among those, B. papayensis Baker (Acari: Tenuipalpidae) occurs in citrus, but seems to be prevalent in coffee plantations. However, it is still unclear the relationship (if any) of B. papayensis with CiLV-C or CoRSV. In order to determine whether or not this mite is capable of transmitting these viruses, one single female specimen was collected from Coffea arabica cv. Catuai in Atibaia, SP-Brazil, and multiplied in laboratory as an isoline. Specimens were mounted in Hoyer’s medium and morphologically confirmed by phase contrast microscopy as B. papayensis, according to the classification of Beard et al. (2015). This isoline population was reared onto healthy coffee leaves, in 25 ± 1°C, 14 h light/10 h dark and 60 ± 10% humidity. RT-PCR assays using primers for the detection of each of the viruses were performed in order to confirm the virus-free colony status. B. papayensis mites were transferred to either coffee leaves exhibiting ringspots or sweet orange fruits symptomatic for leprosis, which served as sources of inocula for 7 days. Viral acquisition was confirmed by RT-PCR of viruliferous mites using specific primers for the detection of CoRSV (Kitajima et al. 2011) or CiLV-C (Locali et al. 2003), according to Kubo et al. (2011). After the acquisition period, 60 mites from each source of inoculum were transferred to 20 Arabidopsis thaliana plants (6 mites per plant), a plant species that can host both. Fifteen days after infestation, typical pinpoint lesions were observed and virus presence was confirmed by RT-PCR in 60% of the CiLV-C- and 30% of the CoRSV-inoculated plants. Additionally, common bean plants (Phaseolus vulgaris cv. Una) were infested with 15 B. papayensis mites from the isoline population reared onto CiLV-C inoculum (one mite per leaf, isolated by entomological glue). Perhaps due to the low efficiency in single mite transmission, only 27% of the leaves became symptomatic. The presence of CiLV-C was confirmed by RT-PCR and sequencing (98% of similarity to GenBank accession no. KP3367461). Fifteen females were collected directly from coffee leaves with CoRSV symptoms in Cordeiropolis, SP-Brazil, and transferred to isolated leaves of common bean plants. Symptoms of necrotic local lesions appeared 10 days after inoculation in 50% of the plants. The presence of CoRSV was confirmed by RT-PCR in both coffee and bean leaves. Amplicons obtained from the latter were sequenced (QG979998) and found 98% identical to CoRSV sequences available in GenBank. This is the first report of common bean as an experimental host of CoRSV. B. yothersi has been shown to transmit cileviruses. B. californicus seems to be the only vector of the dichorhavirus Orchid fleck virus, while B. phoenicis sensu stricto is the vector of the tentative dichorhavirus Citrus leprosis virus N. This is the first confirmation that B. papayensis can transmit CiLV-C and CoRSV. This is also the first time, following the reclassification of the B. phoenicis group, that a transmission was demonstrated by a single species of Brevipalpus for both a dichorha- and a cilevirus. Since this mite species is prevalent in coffee plantations in Brazil, it is likely the main vector of CoRSV under natural conditions.

Citrus leprosis virus N: A New Dichorhavirus Causing Citrus Leprosis Disease.

Citrus leprosis (CL) is a viral disease endemic to the Western Hemisphere that produces local necrotic and chlorotic lesions on leaves, branches, and fruit and causes serious yield reduction in citrus orchards. Samples of sweet orange (Citrus × sinensis) trees showing CL symptoms were collected during a survey in noncommercial citrus areas in the southeast region of Brazil in 2013 to 2016. Transmission electron microscopy analyses of foliar lesions confirmed the presence of rod-like viral particles commonly associated with CL in the nucleus and cytoplasm of infected cells. However, every attempt to identify these particles by reverse-transcription polymerase chain reaction tests failed, even though all described primers for the detection of known CL-causing cileviruses and dichorhaviruses were used. Next-generation sequencing of total RNA extracts from three symptomatic samples revealed the genome of distinct, although highly related (>92% nucleotide sequence identity), viruses whose genetic organization is similar to that of dichorhaviruses. The genome sequence of these viruses showed <62% nucleotide sequence identity with those of orchid fleck virus and coffee ringspot virus. Globally, the deduced amino acid sequences of the open reading frames they encode share 32.7 to 63.8% identity with the proteins of the dichorhavirids. Mites collected from both the naturally infected citrus trees and those used for the transmission of one of the characterized isolates to Arabidopsis plants were anatomically recognized as Brevipalpus phoenicis sensu stricto. Molecular and biological features indicate that the identified viruses belong to a new species of CL-associated dichorhavirus, which we propose to call Citrus leprosis N dichorhavirus. Our results, while emphasizing the increasing diversity of viruses causing CL disease, lead to a reevaluation of the nomenclature of those viruses assigned to the genus Dichorhavirus. In this regard, a comprehensive discussion is presented.

Arabidopsis thaliana as a model host for Brevipalpus mite-transmitted viruses

Brevipalpus-transmitted viruses (BTV) are a taxonomically diverse group of plant viruses which severely affect a number of major crops. Members of the group can be sub-classified into cytoplasmic (BTV-C) or nuclear type (BTV-N) according to the accumulation sites of virions in the infected plant cells. Both types of BTV produce only local infections near the point of inoculation by viruliferous mites. Features of BTV-plant interactions such as the failure of systemic spread in their natural hosts are poorly understood. In this study we evaluated Arabidopsis thaliana, a model plant commonly used for the study of plant-virus interactions, as an alternative host for BTV. Infection of Arabidopsis with the BTV-N Coffee ringspot virus and Clerodendrum chlorotic spot virus, and the BTV-C Solanum violaefolium ringspot virus, were mediated by viruliferous Brevipalpus mites collected in the wild. Upon infestation, local lesions appeared in 7 to 10 days on leaves of, at least, 80 % of the assayed plants. Presence of viral particles and characteristic cytopathic effects were detected by transmission electron microscopy (TEM) and the viral identities confirmed by specific reverse-transcriptase polymerase chain reaction (RT-PCR) and further amplicon sequencing. The high infection rate and reproducibility of symptoms of the three different viruses assayed validate A. thaliana as a feasible alternative experimental host for BTV.

Detection and survey of coffee ringspot virus in Brazil.

Coffee ringspot virus (CoRSV) a member of the proposed genus "Dichorhavirus", was surveyed on commercial and research farms spanning an area responsible for the majority of Coffea arabica production in Brazil. Virus-infected plants were found at one hundred percent of locations (n = 45) sampled. All cultivars, regardless of cherry color, were found to serve as hosts, suggesting that there is limited resistance in commercially employed germplasm. Reverse transcription PCR analysis revealed that the virus is contained within symptomatic lesions, with little systemic spread throughout leaves. Phylogenetic analysis based on the ORF1 (nucleocapsid) gene identified a strong geo-spatial relationship among isolates, which clustered into three clades. Despite low genetic diversity among isolates, variation in symptom expression was observed in the experimental host Chenopodium quinoa. Our analyses support the hypothesis that the spread of CoRSV is constrained by the clonal expansion of thelytokous populations of Brevipalpus phoenicis. The widespread occurrence of this virus suggests that it is much more prevalent than previously thought.

Infestation dynamics of Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) in citrus orchards as affected by edaphic and climatic variables.

Brevipalpus phoenicis (Geijskes) is a cosmopolitan and polyphagous mite that transmits important phytoviruses, such as coffee ringspot virus, passion fruit green spot virus and Citrus leprosis virus C. To characterise the dynamics of the probability and the rate of B. phoenicis infestation in response to edaphic and climatic factors, monthly inspections were performed in nine orchards in a citrus region of the State of Bahia, Brazil, for 35 months. Three fruits per plant were examined using a magnifying glass (10×) on 21 plants distributed along a "W"-shaped path in each orchard. Meteorological data were collected from a conventional station. To determine the correlations among the climatic variables, the data were analysed using Spearman correlations. Variables were selected by principal component analysis, and those that contributed the most to differentiate the groups were evaluated via a Mann-Whitney test. Using the quantile-quantile method, the limit values for the following climatic variables were determined: temperature (24.5 °C), photoperiod (12 h), relative humidity (83%), evapotranspiration (71 mm) and rainy days (14 days). The combination of longer days, higher temperatures, lower relative humidity levels and lower evapotranspiration increased the probability of B. phoenicis infestation, whereas successive rain events decreased that risk. Infestation rates were negatively affected by relative humidity levels above 83% and were positively affected by a decreasing available soil-water fraction and increasing insolation and photoperiod.

Logarithmic scaling and effects of severity levels of ringspot disease on sensory quality of coffee brew

A logarithmic scale was developed to evaluate the severity of the ringspot caused by Coffee ringspot virus (CoRSV) in coffee berries to investigate the effect of disease severity on the quality of brew. The scale comprised seven severity levels (0, 1 to 4%, 4.1 to 8%, 8.1 to 15%, 15.1 to 25%, 25.1 to 50%, 50.1 to 75%, 75.1 to 90%) and was evaluated for accuracy, precision, and reproducibility of severity estimation. The accuracy and precision were determined by simple linear regression between the actual and the estimated severity, considering twelve raters. Brew quality was assessed in berries with three severity levels (4.1 to 8%, 50.1 to 75%, 75.1 to 90%) and healthy berries. The selected fruits were processed and analyzed for electrical conductivity, total sugars, reducing sugars, non-reducing sugars, activity of polyphenol oxidase, and total phenol. The logarithmic scale obtained was easy to use and able to provide quick estimates of disease, good accuracy and good precision. Biochemical analysis of berries showed that polyphenol oxidase activity decreased with increasing severity, whereas total sugars and total phenol levels increased with increasing severity. This result indicated that the higher the CoRSV severity level, the greater the change in compounds directly related to the final quality of brew, which consequently contribute to coffee depreciation. Key words: CoRSV, Coffee ringspot virus, phenolic compounds, polyphenol oxidase.

Primeiro relato do Coffee ringspot virus (CoRSV) no Oeste da Bahia

The coffee ringspot, whose etiologic agent is the Coffee ringspot virus (CoRSV), is a disease that has been causing damage in defoliation in coffee plantations in the states of Minas Gerais and Sao Paulo. The damage ranging from the defoliation accentuated, premature fall of fruits and loss of quality. This work was carried out a study to identify the stainoverride in coffee farms in Western Bahia, Brazil. In Luis Eduardo Magalhaes and Sao Desiderio counties, located in Western Bahia - Brazil, were observed incidences up to 45,6% of coffee plants with ringspot symptoms. Mechanical inoculation of infected material in indicator plants for viruses, Chenopodium ambrosioides, Amaranthus deflexus and Chenopodium quinoa induced typical symptoms confirming the infection by Coffee ringspot virus (CoRSV). This is the first record of CoRSV in Western Bahia, indicating that this virus probably is present in all coffee plantations of the region, established in places with higher temperatures, since this is a factor considered ideal for viral multiplication.

Characterization of Coffee ringspot virus-Lavras: A model for an emerging threat to coffee production and quality

The emergence of viruses in Coffee (Coffea arabica and Coffea canephora), the most widely traded agricultural commodity in the world, is of critical concern. The RNA1 (6552nt) of Coffee ringspot virus is organized into five open reading frames (ORFs) capable of encoding the viral nucleocapsid (ORF1p), phosphoprotein (ORF2p), putative cell-to-cell movement protein (ORF3p), matrix protein (ORF4p) and glycoprotein (ORF5p). Each ORF is separated by a conserved intergenic junction. RNA2 (5945nt), which completes the bipartite genome, encodes a single protein (ORF6p) with homology to RNA-dependent RNA polymerases. Phylogenetic analysis of L protein sequences firmly establishes CoRSV as a member of the recently proposed Dichorhavirus genus. Predictive algorithms, in planta protein expression, and a yeast-based nuclear import assay were used to determine the nucleophillic character of five CoRSV proteins. Finally, the temperature-dependent ability of CoRSV to establish systemic infections in an initially local lesion host was quantified.

Comparison of susceptibility of the pest mite Brevipalpus phoenicis and the predator Agistemus brasiliensis to agrochemicals

Among the pests that attack coffee plants (Coffea spp.), it stands out some species of phytophagous mites which can cause significant losses, such as, Oligonychus ilicis (McGregor, 1917) (Acari: Tetranychidae) and Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae), vector of the coffee ringspot virus (CoRSV). Recent studies have indicated that stigmaeid mites, mainly of the genera Agistemus and Zetzellia, are important natural enemies of pest mites such as B. phoenicis and O. ilicis. The objective of this study was to evaluate the effect of various chemical compounds (insecticides, acaricides and fungicides) used in coffee and/or citrus plantations (or under registration) in Brazil on the mite pest B. phoenicis and the predator Agistemus brasiliensis Matioli, Ueckermann & Oliveira, 2002 (Acari: Stigmaeidae). Various pesticides were tested, using the concentrations recommended for the control of pests on coffee or citrus plants. The applications were performed in a Potter spray tower. It was evaluated the toxicity of chemicals on the adults of both mite species, besides the effect of compounds on the instantaneous growth rates (ri) of the mites. Abamectin, profenophos + cypermethrin, deltamethrin + triazophos, diafenthiuron, fenpropathrin, spirodiclofen and etoxazole were harmfull to B. phoenicis and A. brasiliensis. Cyflumetofen and malathion caused population reductions in B. phoenicis, but did not affect the population growth of A. brasiliensis. Thiophanate-methyl affected the population growth of both species, but was more toxic to A. brasiliensis. Copper oxychloride reduced only the population growth of the predaceous mite.

Common Bean: Experimental Indicator Plant for Citrus leprosis virus C and Some Other Cytoplasmic-Type Brevipalpus-Transmitted Viruses.

Citrus leprosis (CL) caused by Citrus leprosis virus C (CiLV-C) is present in Latin America from Mexico to Argentina, where citrus plants are grown. CiLV-C is transmitted by the tenuipalpid mite, Brevipalpus phoenicis, causing localized lesions on citrus leaves, fruit, and stems. One limitation to study of the virus-vector-host relationship in this pathosystem is the lack of a suitable assay plant. On Citrus spp. used as susceptible hosts, symptoms may take weeks or months to appear after experimental inoculation by viruliferous mites. Common bean (Phaseolus vulgaris) was found to respond with localized necrotic lesions after inoculation with viruliferous B. phoenicis in 5 days. Thus far, 113 tested common bean varieties and lines and some recent accessions of varied genetic background behaved in a similar way. Black bean 'IAC Una' was adopted as a standard test variety. When inoculated leaves were left at 28 to 30°C, the period for the lesion appearance was reduced to only 2 days. Confirmation that the lesions on common bean leaves are caused by CiLV-C were made by transmission electron microscopy, immunofluorescence, enzyme-linked immunosorbent assay, and reverse-transcription polymerase chain reaction specific for CiLV-C. Common bean plants mite-inoculated with some other cytoplasmic-type Brevipalpus-transmitted viruses (BrTVs) (Passion fruit green spot virus, Solanum violaefolium ringspot virus, Ligustrum ringspot virus, and Hibiscus green spot virus) also responded with necrotic local lesions and may serve as test plants for these viruses. Two nuclear types of BrTV (Coffee ringspot virus and Clerodendrum chlorotic spot virus) were unable to produce symptoms on common bean.

IPR 99 - Dwarf arabica coffee cultivar resistant to coffee ringspot virus

'IPR 99' was derived from a cross between "Villa Sarchi 971/10" and "Hibrido de Timor 832/2". It is a dwarf cultivar, resistant to coffee ringspot virus, partially resistant to leaf rust with semi-late ripening. 'IPR 99' presents partial resistance to necrosis and mummification of young fruits on field conditions. It presents special cup quality and high yield in lower and higher temperature coffee regions in Paraná State.

Análise temporal e controle da mancha-anular e do ácaro vetor do Coffee ringspot virus

O objetivo deste trabalho foi avaliar a flutuação populacional do ácaro Brevipalpus phoenicis, vetor do Coffee ringspot virus (CoRSV) - agente causal da mancha-anular do cafeeiro -, bem como a sua distribuição em plantas de café e o efeito de acaricidas no seu controle em lavouras cafeeiras. O experimento foi realizado no Município de Coromandel, na região do Alto do Paranaíba, MG, durante dois anos. No segundo ano, avaliou-se o progresso da doença, e determinou-se a relação entre o crescimento populacional do ácaro e a incidência da doença. Observou-se que a mancha-anular e o ácaro ocorreram durante todo o ano, com maiores populações e incidência da doença nos meses com menores índices pluviais e temperaturas amenas. As análises de Pearson mostraram correlação negativa entre os parâmetros climáticos e a população do ácaro. Na análise da incidência da doença em diferentes épocas, verificou-se correlação positiva entre a primeira avaliação e as avaliações subsequentes. Quanto à distribuição espacial, foi observada a presença do ácaro em toda a planta; porém, as folhas são preferidas pelos adultos, enquanto os frutos são preferidos para oviposição. Os acaricidas são eficientes para manter a população do ácaro em baixos níveis, com consequente diminuição da incidência da doença.

Biological notes and risk status of &lt;i&gt;Brevipalpus phoenicis&lt;/i&gt; (Geijskes, 1939) (Acari: Tenuipalpidae) in New Zealand

The status of the tenuipalpid mite Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae) in New Zealand was previously uncertain. New collection records suggest that this mite is established, at least in the northern North Island. Brevipalpus phoenicis is known to vector a number of plant diseases caused by Rhabdoviriidae (Mononegavirales), including some known to cause serious damage to food crops such as Citrus leprosis virus (CiLV), Passion fruit green spot virus (PFGSV) and Coffee ringspot virus (CoRSV). None of the diseases ectored by this mite are known to be present in New Zealand. Consequently B. phoenicis should still be considered of concern to New Zealand’s biosecurity under some circumstances.