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Phyllosticta citricarpa is an important citrus-pathogen and a quarantine organism in the European Union. Its recently described relative, P. paracitricarpa, is very closely related and not listed as a quarantine organism. P. paracitricarpa is very difficult to distinguish from P. citricarpa, since its morphological features overlap and the barcoding gene sequences that were originally used to delimit them as distinct species have a low number of species-specific polymorphisms that have subsequently been shown to overlap between the two clades. Therefore, we performed extensive genomic analyses to determine whether the genetic variation between P. citricarpa and P. paracitricarpa strains should be considered to represent infraspecific variation within P. citricarpa, or whether it is indicative of distinct species. Using a phylogenomic analysis with 3,000 single copy ortholog genes and whole-genome comparisons, we determined that the variation between P. citricarpa and P. paracitricarpa can be considered as infraspecies variation within P. citricarpa. We also determined the level of variation in mitochondrial assemblies of several Phyllosticta species and concluded there are only minimal differences between the assemblies of P. citricarpa and P. paracitricarpa. Thus, using several orthogonal approaches, we here demonstrate that variation within the nuclear and mitochondrial genomes of other Phyllosticta species is larger than variation between genomes obtained from P. citricarpa and P. paracitricarpa strains. Thus, P. citricarpa and P. paracitricarpa should be considered as conspecific.

Citrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography–mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively. [ABSTRACT FROM AUTHOR]

This review deals with major diseases caused by fungi and oomycetes in the citrus supply chain, including post-harvest fruit diseases, and summarizes the strategies and techniques that may be adopted to prevent the damages and losses they cause. Its scope is to highlight the contribute that smart technologies provide towards new solutions for sustainable and safe management strategies of these diseases. Particular attention is given to the application of biopesticides, natural substances, resistance inducers and biostimulants to prevent fruit rots. The review focuses also on mycotoxins and mycotoxigenic fungi that contaminate fresh fruit and food products derived from citrus fruit, an aspect that has been little investigated and regulated so far. An additional relevant aspect addressed by the review is the early detection and routine diagnosis of fungal and oomycete pathogens that threat the international trade and long-distance shipment of citrus fruit, with a particular emphasis on quarantine pathogens. In this respect, the opportunities offered by new practical, rapid, sensitive and robust molecular diagnostic methods are briefly discussed. [ABSTRACT FROM AUTHOR]

Introduction: The use of chemical fungicides to combat disease has made a substantial contribution to food quality and security. Nonetheless, their applications have been limited due to environmental and health concerns, unaffordability, and the fact that pathogens have acquired resistance to some of these fungicides. Alternative eco-friendly and safe control methods should be explored. The current study investigated the influence of citrus rind phenolic compounds against Phyllosticta citricarpa infection by metabolic profiling of two citrus cultivars with varying degrees of susceptibility to infection. Methods: Chromatographic data obtained by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC) was subjected to multivariate data analysis to identify biomarkers associated with the tolerant cultivar. The identified biomarkers were tested in vitro against P. citricarpa. Results: Seville oranges, a tolerant cultivar, displayed higher levels of phenolic content and lower total sugar content, that are both associated with lower susceptibility to citrus black spot infection. The generated Principal Component Analysis (PCA) and Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA) models gave an overview of the data set and identified components that may be responsible for the differences in susceptibility between the two cultivars. Candidate biomarkers associated with tolerance were identified as naringin, neoeriocitrin, bruteiridin, melitidin, and lucenin-2. Conclusion: Naringin, a major candidate biomarker was able to inhibit the growth of the pathogen at 10 000 ppm. [ABSTRACT FROM AUTHOR]

Citrus black spot (CBS), caused by Phyllosticta citricarpa, is an important disease of citrus, an economically important fruit crop worldwide and particularly in Tunisia. CBS was recently detected in Tunisia and this study revealed that it is widespread in the governorates of Nabeul and Sousse. The highest incidence of CBS was found in the Bouargoub region (73.7%), while the lowest was observed in Soliman (25.0%) in the Nabeul governorate. The surveys revealed that CBS affected mainly lemon (Citrus limon). The symptoms of CBS observed were hard spots on fruits, twigs, and leaves, as well as false melanose on fruits. Symptoms were observed in both mature and immature citrus fruits, but disease incidence was higher in mature (97.0%) than that in immature fruits (2.95%). In this study, morphological and molecular identifications confirmed the presence of P. citricarpa. This is the first time that the extent of CBS has been documented in a Mediterranean citrus area. [ABSTRACT FROM AUTHOR]

ABSTRACT Copper-based formulations are used extensively to manage two of the leading citrus diseases that affect the São Paulo (SP) citrus belt, Brazil, namely, citrus canker and citrus black spot. Since the early 2010s, studies have identified the critical period and ideal frequency of copper applications to control each disease. Consequently, results have led to an optimized joint spray program replacing the traditional one and an essential reduction in copper use without affecting control quality. These research studies have presented the benefits of copper use reduction, although the potential economic impact has not been calculated. The present study aimed to estimate the value of copper potentially saved by adopting the optimized spray program for citrus canker and citrus black spot control per hectare and in the entire SP citrus belt since 2017, when both diseases began to be managed concomitantly. The optimized program allowed for a ~56 % reduction in metallic copper usage (~10 kg ha–1 per season). This amount of copper saved corresponds to ~120 dollars per hectare per season. Moreover, if the optimized program were to be used throughout the SP citrus belt, the average saving is estimated at ~56 million dollars per season. These results showed that economic analysis reinforces the value of scientific research herein by adjusting disease management for the production chains’ maintenance, development, and sustainability.

• Infraspecific variation between P. citricarpa and P. paracitricarpa is minimal. • Other Phyllosticta species show more infraspecific genomic variation. • Mitochondrial assemblies of P. citricarpa / P. paracitricarpa show minimal differences. • P. citricarpa and P. paracitricarpa should be treated as conspecific. Phyllosticta citricarpa is an important citrus-pathogen and a quarantine organism in the European Union. Its recently described relative, P. paracitricarpa , is very closely related and not listed as a quarantine organism. P. paracitricarpa is very difficult to distinguish from P. citricarpa , since its morphological features overlap and the barcoding gene sequences that were originally used to delimit them as distinct species have a low number of species-specific polymorphisms that have subsequently been shown to overlap between the two clades. Therefore, we performed extensive genomic analyses to determine whether the genetic variation between P. citricarpa and P. paracitricarpa strains should be considered to represent infraspecific variation within P. citricarpa , or whether it is indicative of distinct species. Using a phylogenomic analysis with 3,000 single copy ortholog genes and whole-genome comparisons, we determined that the variation between P. citricarpa and P. paracitricarpa can be considered as infraspecies variation within P. citricarpa. We also determined the level of variation in mitochondrial assemblies of several Phyllosticta species and concluded there are only minimal differences between the assemblies of P. citricarpa and P. paracitricarpa. Thus, using several orthogonal approaches, we here demonstrate that variation within the nuclear and mitochondrial genomes of other Phyllosticta species is larger than variation between genomes obtained from P. citricarpa and P. paracitricarpa strains. Thus, P. citricarpa and P. paracitricarpa should be considered as conspecific. [ABSTRACT FROM AUTHOR]

Citrus black spot (CBS), with Phyllosticta citricarpa (McAlpine) van der Aa as the causal agent, is a disease that affects Citrus spp. It produces considerable economic losses due to the staining and premature fall of the fruits, and the limitations for their export to countries where the pathogen is considered a quarantine pest. Recent studies provided novel results on this subject. Among them, the description of new species of the genus Phyllosticta associated with citrus stands out, and it hinders the diagnosis of P. citricarpa. In addition, an atypical life cycle was detected for this fungus in some citrus regions, while the development of fungal-resistance in populations of this pathogen and effective fungicides and biological control agents for its management have been reported. Taking these aspects into consideration, this work offers a current overview of CBS in the world and in Cuba, attending to the damage it causes, its economic impact, the characteristics of the causal agent that influence epidemiology and its management, as well as its main challenges and future prospects. [ABSTRACT FROM AUTHOR]

Citrus canker and citrus black spot are two of the most important diseases in the São Paulo (SP) citrus belt, Brazil. Canker control was based on an eradication program for six decades, but after a change in the legislation in 2017, the disease has been managed along with black spot. Although copper is a common pesticide for control of canker and black spot, spray setups have been established separately for each disease. The aim of this study was to determine copper rates and spray intervals for joint management of the two diseases. Two field trials (one for each disease) were conducted during two seasons. Control of canker or black spot was assessed with sprays at 14 or 21-day intervals using 10 to 63 mg metallic copper/m3 tree canopy. Copper was also assessed for efficacy against black spot at 28-day spray intervals using 32 and 53 mg/m3. Copper treatments with 42 mg/m3 every 21 days and 32 mg/m3 every 14 days showed the best cost-benefit for canker control. These treatments reduced leaf canker incidence and fruit drop by up to 60%. Black spot symptoms and fruit drop were consistently reduced (by up to 90% and 60%, respectively) in both seasons by rates from 32 to 63 mg/m3 and intervals of up to 28 days. Thus, the combination of 32 mg metallic copper/m3 sprayed at 14 day intervals as well as 42 mg/m3 every 21 days are the most cost-effective for joint management of citrus canker and black spot to be used in areas where both diseases are endemic and cause considerable yield losses. [ABSTRACT FROM AUTHOR]

Background: Despite technical improvements in the citrus chain and leadership in orange production achieved in the past decades, premature fruit drop remains a major component of crop loss in São Paulo state citrus belt, the largest sweet orange production area in the world. The present study aimed to determine, during five consecutive seasons, the impact of the diseases and pests on premature fruit drop in the orange belt. Results: Fruit drop due to the main diseases and pests averaged approximately 11.0%, which corresponded to approximately 63% of the annual fruit drop. The average fruit drop rate due to fruit borer and fruit flies combined was 4.0%, Huanglongbing (HLB) 3.3%, black spot 2.6%, leprosis 1.0% and citrus canker 0.3%. The average amount of fruit drop (million 40.8 kg boxes) and value of crop losses (million US$ dollars), in five seasons, were 12.7 and 66.2 for fruit borer/fruit flies, 11.0 and 57.9 for HLB, 8.1 and 42.2 for black spot, 3.1 and 15.6 for leprosis, and 0.9 and 4.9 for citrus canker, respectively. Conclusion: Fruit borer and fruit flies (combined), HLB, black spot, leprosis and citrus canker are, in this order, the main diseases and pests in the orange belt of São Paulo state. All of these causes significantly increased the overall fruit drop rate in the evaluated seasons. The results will contribute to the development of the Brazilian citrus industry, while showing to other citrus‐growing regions the potential that diseases and pests have to jeopardize production. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Citrus black spot (CBS) may cause substantial yield loss in sweet orange orchards. Severity and distribution of CBS symptoms on fruit may be variable and not all affected fruit may fall. However, the relationship between CBS symptoms and yield loss has not yet been investigated. This study aimed to determine CBS characteristics associated with premature fruit drop. A set of fruit was removed from the tree to measure the detachment force and another set of dropped fruit was collected from Pera and Valencia sweet orange orchards in three municipalities in Sao Paulo state, Brazil. CBS severity, distance of the nearest lesion from the peduncle, and fruit peel colour were assessed in both fruit sets. CBS severity was consistently related with the force to remove fruit and hence associated to the premature fruit drop, irrespective of the cultivar and location. The segmented linear regression showed that the fruit detachment force was reduced abruptly, at a rate of 7% for every 1% increase in disease severity up to 4.2 ± 1.0% CBS severity and, above this breakpoint, the force decreased slightly at a rate of 1.5%. Taking into account all orchards, the proportion of dropped fruit with CBS severity higher than the breakpoint was approximately 90%. This study provides a better understanding of the relationship between CBS severity and premature fruit drop of sweet orange. CBS severity breakpoint may be used as a reference to anticipate harvest and reduce CBS‐related yield loss in orchards intended for juice processing. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mineral oil added to fungicide spray mixtures has been a frequently used strategy to control citrus black spot (CBS) worldwide. Although mineral oil may increase the efficacy of control, its use represents around 15% of the costs of a CBS spray program. This study aimed to assess the performance of different proportions of mineral oil added to a fungicide tank mixture for CBS control in young (less than 10 years old) and old (more than 12 years old) sweet orange orchards of early ('Hamlin'), mid‐season ('Pera') and late‐maturing ('Valencia') cultivars in São Paulo state, Brazil. The efficacy of 0.15%, 0.20% or 0.25% mineral oil added to a fungicide spray mixture was determined by assessing CBS incidence, severity and fruit drop in six orchards over two seasons. RESULTS: Fungicide programs with or without oil were effective in reducing 100% CBS symptom expression in both young and old 'Hamlin' orchards and in the young 'Pera' orchard. The lowest mineral oil rate tested (0.15%) showed a reduction in CBS intensity of around 90%, similar to the highest rate tested in the old 'Pera' orchard. The highest cost–benefit program to control CBS in the old 'Valencia' orchard was obtained with the mineral oil rate of 0.25%, commonly used in the São Paulo citrus belt, which reduced CBS severity by up to 97%. CONCLUSION: This study demonstrated that mineral oil rates for CBS control can be adjusted according to tree age and cultivar. These findings contribute to the establishment of more sustainable citrus production by reducing spray costs while maintaining the efficacy of CBS control. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Orange juice is a major agricultural product, and oranges are among the most widely sold fresh fruits in several countries. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa, affects almost every species of citrus, causing a esthetic depreciation of the fruit and fruit drop, with consequent financial loss for its in natura commercialization. Fungicides are the major control measure for CBS, but have limited efficiency and high cost, and give rise to fungal strains resistant to these products. This work assayed the production of antifungal compounds by Bacillus spp. isolates and tested the potential of two isolates from B. subtilis (ACB-AP3 and ACB-83) for controlling CBS under field conditions with two previously untested orange varieties. A total of 15 isolates produced cell-free, thermostable or volatile compounds effective in suppressing P. citricarpa growth in vitro. It was possible to detect the production of two antibiotics (iturin and surfactin) by B. subtilis ACB-83. Additionally, B. subtilis isolates ACB-AP3 and ACB-83 displayed significant effects in controlling the disease under field conditions. [ABSTRACT FROM AUTHOR]

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Citrus black spot is an important fungal disease of citrus resulting in fruit drop and rind blemish in tropical and subtropical production areas. The disease is incited by the fungus Phyllosticta citricarpa (McAlpine) van der Aa (synonym: Guignardia citricarpa Kiely), with control currently relying on the application of fungicides. Because the presence and expression of resistance is poorly understood, we sought to develop a method for inoculating fruit in the field that gives reproducible symptoms of citrus black spot consistent with natural field infection. We subsequently validated this method by screening 49 citrus accessions and characterized their qualitative expression of citrus black spot symptoms. Challenge inoculations were undertaken with a known isolate of P. citricarpa, and control fruit were inoculated with water or the endophyte P. paracapitalensis Guarnaccia & Crous. Our results showed that all mandarin, sweet orange, lemon and papeda types were susceptible; pummelo, lime, and sour orange types expressed immunity; while various hybrids were susceptible, resistant and immune. Hybrid progeny from crosses using pummelo [Citrus maxima (Burm.) Merr.] as a parent showed preliminary evidence of segregation for citrus black spot immunity. The implications of these results to achieve genetic improvement for citrus black spot resistance in citrus breeding programs are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Citrus black spot (CBS) is caused by Phyllosticta citricarpa , which is regarded as a quarantine pathogen in certain countries. Pest risk assessments disagree on the risk of fruit as a pathway for introduction of the pest to new areas. Some countries accordingly regulate the movement of fruit from production regions where CBS occurs. Preharvest fungicide sprays are very effective in controlling CBS, but cannot consistently achieve complete control. The effect of postharvest treatments on CBS infections and on the reproductive ability of P. citricarpa in lesions that formed after these treatments was studied. Trials were conducted using naturally infected ‘Eureka’ lemon and Valencia orange fruit. Asymptomatic fruit were treated using commonly used packhouse sanitation and fungicide treatments, and cold storage (individually and combined), as well as alternative stand-alone treatments. After treatment, fruit were stored for 5 weeks (in the dark) at ambient temperature (20–22 °C) or −0.5–7 °C, whereafter they were incubated for a further 2 weeks at conditions conducive to expression of symptoms and formation of pycnidia. Individual treatments generally resulted in variable levels of control. The combination of packhouse treatments (including pre-packhouse drench with guazatine or propiconazole in combination with pyrimethanil, thiabendazole and 2,4-D; chlorine wash; dip treatment in imazalil; and brush application of a wax coating incorporated with imazalil, thiabendazole and 2,4-D) consistently showed moderate to high levels of control of CBS development from latent infections on lemons (32.4–43.4% for incidence and 61.6–68.3% for severity) and oranges (58.3–85.7% for incidence and 54.1%–88.8% for severity). However, cold storage subsequent to packhouse treatments (as is common shipping protocol) further improved the levels of control (44.0–58.3% for incidence and 78.1–82.5% for severity on lemons; 66.1–93.5% for incidence and 85.3–98.5% for severity on oranges). An average of 10% of new lesions on lemons and 15% on oranges formed pycnidia, indicating that P. citricarpa generally had a low reproductive capability in fruit lesions, which was in most cases further diminished by the combination of treatments followed by cold storage. [ABSTRACT FROM AUTHOR]

Summary: Terpene volatiles play an important role in the interactions between specialized pathogens and fruits. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa, is associated with crop losses in different citrus‐growing areas worldwide. The pathogen may infect the fruit for 20–24 weeks after petal fall, but the typical hard spot symptoms appear when the fruit have almost reached maturity, caused by fungal colonization and the induction of cell lysis around essential oil cavities. d‐Limonene represents approximately 95% of the total oil gland content in mature orange fruit. Herein, we investigated whether orange fruit with reduced d‐limonene content in peel oil glands via an antisense (AS) approach may affect fruit interaction with P. citricarpa relative to empty vector (EV) controls. AS fruit showed enhanced resistance to the fungus relative to EV fruit. Because of the reduced d‐limonene content, an over‐accumulation of linalool and other monoterpene alcohols was found in AS relative to EV fruit. A global gene expression analysis at 2 h and 8 days after inoculation with P. citricarpa revealed the activation of defence responses in AS fruit via the up‐regulation of different pathogenesis‐related (PR) protein genes, probably as a result of enhanced constitutive accumulation of linalool and other alcohols. When assayed in vitro and in vivo, monoterpene alcohols at the concentrations present in AS fruit showed strong antifungal activity. We show here that terpene engineering in fruit peels could be a promising method for the development of new strategies to obtain resistance to fruit diseases. [ABSTRACT FROM AUTHOR]

Citrus black spot (CBS) damage and Phyllosticta citricarpa inoculum tend to increase in old orchards and in late-maturing cultivars of sweet orange. However, CBS control in São Paulo citrus belt is based on standard fungicide program of 180–220 days of fruit protection, regardless of cultivar and orchard age. This study aimed to investigate whether the protection period may be adjusted based on the cultivar maturation and age of orchards intended for juice processing. The efficacy of protection periods of 60, 100, 140, 180, 220 and 260 days was determined by assessing CBS incidence and severity and CBS-related fruit drop in 12 orchards over two seasons. The standard protection period, with 180 days targeted for mid-age and 220 days for old orchards, was the most cost effective for mid-season and late-maturing cultivars. These protection periods resulted in a significant reduction in CBS severity and fruit drop by up to ∼95% and ∼50%, respectively. For early-maturing cultivars, the duration of CBS spray program may be drastically reduced to 60 days for mid-age orchards and to 100 days for old orchards. These protection periods significantly reduced CBS severity and fruit drop by up to ∼92% and ∼50%, respectively. These adjustments in CBS fungicide protection period based on cultivar and orchard age may save up to US$14.3 million per season if adopted throughout the main Brazilian citrus belt. The results of this study allow citrus growers to save inputs, reduce costs, improve the operational efficiency within the farm and contribute to a more sustainable citrus industry. • Citrus black spot spray protection may be based on the cultivar maturation and orchard age. • Old orchards of mid-season or late-maturing cultivars require longer protection periods i.e. 220 days. • Mid-age orchards of early-maturing cultivars require shorter protection periods i.e. 60 days. [ABSTRACT FROM AUTHOR]

Abstract The Plant Health Panel reviewed the paper by Guarnaccia et al. () and compared their findings with previous predictions on the establishment of Phyllosticta citricarpa. Four species of Phyllosticta were found by Guarnaccia et al. () in Europe. P. citricarpa and P. capitalensis are well‐defined species, with P. citricarpa recorded for the first time in Europe, confirming predictions by Magarey et al. () and EFSA (2008, 2014, 2016) that P. citricarpa can establish in some European citrus‐growing regions. Two new species P. paracitricarpa and P. paracapitalensis were also described, with P. paracitricarpa (found only in Greece) shown to be pathogenic on sweet orange fruits. Genotyping of the P. citricarpa isolates suggests at least two independent introductions, with the population in Portugal being different from that present in Malta and Italy. P. citricarpa and P. paracitricarpa were isolated only from leaf litter in backyards. However, since P. citricarpa does not infect or colonise dead leaves, the pathogen must have infected the above living leaves in citrus trees nearby. Guarnaccia et al. () considered introduction to be a consequence of P. citricarpa having long been present or of illegal movement of planting material. In the Panel's view, the fruit pathway would be an equally or more likely origin. The authors did not report how surveys for citrus black spot (CBS) disease were carried out, therefore their claim that there was no CBS disease even where the pathogen was present is not supported by the results presented. From previous simulations, the locations where Guarnaccia et al. () found P. citricarpa or P. paracitricarpa were conducive for P. citricarpa establishment, with number of simulated infection events by pycnidiospores comparable to sites of CBS occurrence outside Europe. Preliminary surveys by National Plant Protection Organisations (NPPOs) have not confirmed so far the findings by Guarnaccia et al. () but monitoring is still ongoing.

ABSTRACT Citrus black spot, a fungal disease caused by the quarantine fungus Guignardia citricarpa, restricts the exportation of fresh fruit to countries in the European Union. The occurrence of latent infections and the time required for diagnosis using conventional methods have brought about the need to validate fast, efficient and reproducible molecular techniques to detect the pathogen in asymptomatic tissue. As such, this study aims to detect G. citricarpa in the symptomatic fruit and asymptomatic leaf tissue of sweet oranges by conventional and real-time polymerase chain reaction (PCR). Specificity and limit of detection (LOD) were assessed in tissue samples of fruit lesions and asymptomatic leaves. Low concentrations of the fungus were found in asymptomatic leaves. Under these conditions, real-time PCR proved to be viable, reproducible and highly sensitive to detection of the pathogen.

Citrus black spot (CBS) is a quarantine disease, reported in Florida in 2010. The pathogen, Phyllosticta citricarpa ( Pc ), survives in twigs and leaf litter during the off-season. Speeding up leaf litter decomposition could contribute to reducing disease pressure and potential spread. Objectives were to investigate (a) effects of bagasse, cellulolytic microbes and urea on leaf litter decomposition; (b) relations between litter composition, moisture content and decomposition rate; and (c) effects of the treatments on Pc s urvival. Two laboratory and two field experiments were conducted in Northern Florida, where the pathogen is absent. In microcosms, the effects of bagasse ± cellulolytic microbes, just microbes, urea, and a control treatment were compared with respect to decomposition of Pc -inoculated mature sweet orange leaves on soil, Pc reisolation and detection by qPCR. In two disease-free sweet orange groves, effects of bagasse and urea on decomposition of nylon-bagged sweet orange leaves on soil were compared to a control at various distances from micro-sprinklers. Bagasse resulted in a leaf dry weight reduction of 93% in microcosms and 67% in groves compared to 36% in both controls after two months. Dry weight reductions declined with distance from sprinklers, except in the bagasse treatment which maintained leaf moisture content. Pc was not reisolated, but its DNA was detected in all inoculated but not in non-inoculated samples after one month. Bagasse enhanced decomposition of sweet orange leaves on soil. Additional experiments are needed in CBS affected groves to investigate effects of bagasse on Pc survival in leaf litter. [ABSTRACT FROM AUTHOR]

This study highlighted the effect of planting coast-cross grass and forage peanut cv. Amarilis between rows of Natal oranges on spreading of Guignardia citricarpa ascospores and consequent citrus black spot control. Treatments evaluated were: 1- conventional cultivation, free of fungicides; 2- conventional cultivation, using protective fungicides; 3- inter-crop cultivation of coast-cross grass between rows of citrus crops and; 4- inter-cropping cultivation of forage peanut between the rows of citrus crops. Quest Volumetric Spore SystemTM traps were set in order to determine the number of ascospores released. A total of 33 inspections were conducted weekly, from the end of August until early September the following year. A diagrammatic scale was used to determine the severity of the disease as well as the percentage of fruits having a commercial standard. The coast-cross grass was more effective in reducing the number of ascospores produced, whose average statistics were lower than in the conventional treatments, free-fungicides. The inter-crop and conventional cultivation method coupled with fungicide treatment was more effective in reducing the severity of citrus black spot symptoms, and differs statistically from the fungicide-free control method. These methods also resulted in a higher percentage of fruits of a commercial standard, ranging from the 89% through the 91% percentile, and the cultivation, free of fungicides, fell within the 73%.

Abstract Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) was asked to assess two publications, authored by Magarey et al. and Martínez‐Minaya et al. from 2015, with regard to a need to update the EFSA Scientific Opinion from 2014 on the risk of Phyllosticta citricarpa (Guignardia citricarpa) for the EU territory. The EFSA PLH Panel was also requested to assess any other relevant scientific information published after the finalisation of the EFSA Scientific Opinion. The fungus P. citricarpa (McAlpine) Van der Aa causes the citrus disease citrus black spot (CBS), and is regulated as quarantine organism in Council Directive 2000/29/EC. The Panel assessed the two publications in detail as well as all relevant publications published until 31 March 2016. A comparison with the EFSA PLH Panel () was made, survey data on CBS from South Africa used in Magarey et al. () were evaluated, and the citrus production areas in the EU were characterised and compared with results from Magarey et al. (). Uncertainty and model sensitivity were discussed. It was concluded that the evidence presented in Magarey et al. from 2015 does not require an updating of EFSA PLH Panel (). The conclusion in the Opinion that probability of CBS establishment in the EU is moderately likely is not affected by the paper by Magarey et al. () predicting establishment in some of the EU locations they selected. The high level of uncertainty regarding the probability of establishment is also unchanged by Magarey et al. (). The Panel concluded that Martínez‐Minaya et al. (2015) does not provide new evidence requiring an update to EFSA PLH Panel (), principally because it had already been concluded that global climate zones are based on factors and thresholds that are broad and not necessarily representative of those that are critical for the pathogen and its host.

The ability of isolates of Bacillus subtilis and Trichoderma spp. to control citrus black spot (CBS) was investigated in ´Natal´ sweet orange orchards. The first experiment was conducted during the 2001/2002 season and four isolates of B. subtilis (ACB-AP3, ACB-69, ACB-72 and ACB-77), applied every 28 days, alone or in combination were tested and compared with fungicide treatments. Two other experiments were carried out during the 2002/2003 season, where the same isolates of Bacillus and two isolates of Trichoderma (ACB-14 and ACB-40) were tested being applied every 28 days in the second experiment, and every 15 days in the third experiment. In the first experiment, the treatment with ACB-69 differed statistically from the control, but did not differ from other biological control agents or mixture of Bacillus isolates. In the second experiment, the treatments with ACB-69 and ACB-AP3 resulted in smaller disease index compared with the control treatment. However, this result was not repeated in the third experiment, where the isolates were applied every 15 days. Disease severity was high in both evaluated seasons and the fungicide treatment was the most effective for disease control.

O objetivo deste trabalho foi determinar o comportamento de variedades de laranjas-doces quanto à resistência a Guignardia citricarpa, agente causal da mancha preta dos citros (MPC). Os ensaios foram conduzidos em dois campos, nos municípios de Rincão e Tambaú, SP. As mudas foram formadas em viveiro localizado na Estação Experimental de Citricultura de Bebedouro-SP. Para tal, foram utilizadas borbulhas de plantas cítricas existentes no Banco Ativo de Germoplasma de Citros da Estação Experimental de Citricultura de Bebedouro (EECB), Bebedouro-SP. Avaliou-se a severidade da doença por meio de escala de notas, de zero (ausência de sintomas) a seis (sintomas severos). A partir de tais dados, foi calculado o valor do índice de doença (ID). Em 2007, no experimento de Rincão, dentre as 65 variedades avaliadas, apenas 59 produziram frutos, sendo constatada ausência de sintomas da doença em Castellana, Maçã e Olivelands. Nas demais variedades, os níveis de severidade variaram de 0,35 para Grada a 3,0 para China SRA-547. Para Tambaú, os valores de severidade variaram de 0,40 para a variedade Cadenera a 2,46 para Pera. No ano de 2008, em Rincão, todas as variedades mostraram-se suscetíveis. Os níveis de severidade verificados variaram de 0,18 para a variedade Belladona, e 3,92 para Vera 97. Em Tambaú, somente a variedade Navelina não apresentou sintomas da MPC. Foi observado que, dentre as plantas que frutificaram, e com exceção daquelas cujos frutos mostraram-se assintomáticos, os valores de severidade variaram de 0,11 para a variedade Tua Mamede a 3,57 para Amares.The objective of this research was to determine the variety behavior of sweet oranges as to their resistance to Guignardia citricarpa, a causal agent of citrus black spot (CBS). The tests were conducted in two fields in the cities of Rincão and Tambaú, SP. The seedlings were formed in a nursery located in the Experimental Station of Citriculture (EECB) in Bebedouro, SP. For this, citrus plant buds present in the Active Bank of Citrus Germoplasm (EEBC), were used. The severity of the disease was evaluated by using a grade scale from zero (absence of symptoms) to six (maximum severity). Using this data the disease index (DI) was calculated. In the 2007 harvest, the tests in Rincão showed that only 59 out of the 65 varieties evaluated produced fruit, verifying the absence of the disease symptoms in Castellana, Maçã and Olivelands. In the other varieties, the severity levels vary between 0.35 in Grada, and 3.0 in China SRA-547. In Tambaú, the severity values varied from 0.40 in Cadenera, and 2.46 in Pêra. In 2008, all of the varieties in Rincão showed to be susceptible. The severity levels verified, varied from 0.18 in Belladona and 3.92 in Vera 97. In Tambaú, only the Navelina variety showed no CBS symptoms. Among the plants that flourished, it was observed that the values of severity varied from 0.11 in Tua Mamede and 3.57 in Amares, with the exception of those whose fruits showed to be asymptomatic.

Os níveis de incidência e severidade de sintomas das doenças resultam da interação hospedeiro-patógeno-ambiente. Nesse contexto, a favorabilidade do ambiente, em particular, depende do nível de umidade, intensidade de radiação solar, luminosidade e molhamento foliar, dentre outros fatores. Por outro lado, a magnitude de expressão desses fatores é dependente do ciclo e porte das plantas, e possivelmente, também, do alinhamento de plantio. No presente estudo, foi avaliada a influência dos alinhamentos de plantio N-S, L-O, NE-SO E NO-SE no desempenho agronômico de plantas de laranjas 'Natal'e 'Valência', assim como na severidade de sintomas da mancha-preta-dos-citros (MPC), causada por Guignardia citricarpa. Para tal, foram selecionadas cinco propriedades distribuídas ao longo do cinturão citrícola paulista, de talhões semelhantes, a partir das quais foram coletadas amostras de 50 frutos, em dez plantas de mesma linha, da região central dos mesmos. Tais frutos foram levados para laboratórios e analisados quanto aos níveis de severidade de sintomas da MPC, produção e qualidade do suco. Constatouse que os frutos oriundos de pomares implantados no alinhamento N-S apresentavam menores níveis de severidade da doença, enquanto no alinhamento NE-SO, os mais elevados. Propriedades localizadas mais ao sul do Estado de São Paulo apresentaram menores níveis de doença, provavelmente em consequência da ocorrência recente da doença em tais áreas. Em relação à produção, os alinhamentos de plantio N-S e L-O proporcionaram maior número de frutos por planta, assim como quanto ao número de caixas por planta. Por outro lado, a menor produção foi verificada nos alinhamentos NO-SE. Em relação à qualidade do suco, não foi possível estabelecer um padrão definido em termos de ratio e ºBrix e os respectivos alinhamentos de plantio. Foi verificado que os valores de ratio foram menores nos frutos de pomares localizados mais ao sul do Estado, de maiores latitudes.The levels of incidence and severity of disease symptoms are a result of the host-pathogenenvironment integration. in this context, a favorable environment, in particular, depends on the level of humidity, intensity of solar radiation, luminosity and leaf wetness among other factors. on the other side, the magnitudes of these factors' expressions are dependent upon the plant's cycle and size, and possibly the crop alignment as well. In the present study, five properties distributed along the citrus agricultural belt of São Paulo were selected. With similar orchards and crop orientation going north-south, east-west, northeast-southwest and northwest-southeast, from which samples of 50 fruits from ten plants of the same central tree line were collected. These fruits were taken to a laboratory and analyzed for severity levels of citrus black spot (Guignardia citricarpa), production and juice quality. it was concluded that the fruits from crops in the east-west orientation presented lower symptom severity, while the north-south orientation, had the highest levels. Also, the farms located further south of São Paulo state, showed lower levels of the disease, probably due to the fact that such areas have shorter periods of disease occurrences. in relation to production, the north-south and east-west crop orientations produced the highest amount of boxes per plant, while the northwest-southeast and northeast-southwest had the lowest production levels. As for the juice quality, there was no concluding data to establish a defined standard in terms of ratio and ºBrix on the respective crop alignment. The relation between the latitude and ratio value was declared to be consistently lower in citrus orchards located further south in the state of Sao Paulo.

O presente trabalho teve por objetivo avaliar a influência de diferentes concentrações de ethephon na expressão precoce de sintomas de Guignardia citricarpa em frutos de laranjeira 'Pêra-Rio'. Para tal, frutos assintomáticos e isentos de aplicações com fungicidas, com 20 e 28 semanas após a queda de pétalas, foram coletados em área de comprovada existência da doença, no município de Conchal-SP e levados ao Laboratório de Fitopatologia da FCAV/UNESP, em Jaboticabal-SP, onde foram tratados com soluções nas seguintes doses de ethephon: i) 1,57 g L-1; ii) 2,10 g L-1; iii) 2,42 g L-1; iv) Testemunha (água). Todas acrescidas de imazalil a 0,25 g L-1, para prevenir podridões de pós-colheita. Após os tratamentos, os frutos foram mantidos em câmara incubadora para B.O.D., calibrada à temperatura de 25ºC ±1ºC, por 15 dias. Posteriormente, os frutos foram submetidos a quatro avaliações, em intervalos semanais, sendo atribuídas notas que variaram de zero (ausência de sintomas) a 6 (sintomas severos). Os dados da severidade da doença observados nos frutos colhidos prematuramente e submetidos aos diferentes tratamentos com ethephon foram comparados aos observados em frutos ensacados e não ensacados, mantidos no campo até a maturação natural. Constatou-se maior equivalência de sintomas nos frutos com idade entre 20 e 28 semanas, quando estes foram tratados com 2,10 g L-1 de ethephon e avaliados entre 28 e 35 dias. Concluiu-se que o emprego de ethephon, nestas condições, viabilizou a expressão precoce dos sintomas da mancha preta em frutos contendo infecções quiescentes de G. citricarpa, com antecedência de, pelo menos, 105 dias antes da colheita. Tal resultado constitui-se, portanto, em alternativa de grande aplicabilidade na detecção precoce de sintomas de mancha preta.The aim of this study was to evaluate the influence of different ethephon rates in the precocity expression of symptoms of black spot caused by Guignardia citricarpa in fruits 'Pêra-Rio' sweet orange, in the orchard located in Conchal, SP. Asymptomatic fruits without fungicides applications and with 20 and 28 weeks after petal fall were collected and taken to the Laboratory of Plant Pathology of FCAV/UNESP, in Jaboticabal/SP, where they were treated with the following ethephon rates: i) 1.57 g L-1; ii) 2.10 g L-1; iii) 2.42 g L-1; iv) (water) (control). For all treatments, Imazalil at 0.25 g L-1 was added to prevent post harvest fungal disease. After the treatments, the fruit were kept in a chamber with a temperature of 25ºC ± 1ºC, during 15 days. Therefore, the fruits were evaluated four times with weekly interval using a scale from 0 (absence of symptoms) to 6 (severe symptoms). The data of disease severity observed in fruits colleted prematurely, under different ethephon rates were compared to those fruits bagged and unbagged remained in orchard until natural maturation. Major symptoms equivalence was verified in fruits with age 20 and 28 weeks, when they were treated with 2.10 g L-1 of ethephon, and evaluated between 28 and 35 days. It is concluded that the use of ethephon in this conditions may cause a precocious expression of symptoms of black spot in fruits with quiescent infections of G. citricarpa with 105 days before of harvest. These results are an alternative of great applicability to precocious detection of citrus black spot.

Citrus black spot (CBS) is a disease caused by the fungus Phyllosticta citricarpa that is associated with significant yield losses. The pathogen forms airborne ascospores that are collected in dead fallen leaves as well as waterborne conidia that are common in lesions on mature fruits and occasionally in leaves and dead twigs. In Brazil, cultural management combined with the application of systemic, protective fungicides is a practice adopted to reduce both inoculum sources. Nevertheless, the removal of mature infected fruits, dead twigs, and dead fallen leaves has not been shown to reduce the extent of disease. Moreover, the increasing use of fungicides has led to the selection of resistant strains, as well as human health concerns. To better understand this pathosystem and how the pathogen overcomes control measures currently in use, we evaluated branches at different growth stages in the field, the viability of the pathogen in detached branches, and the possibility of plant colonization through leaves. We observed that living branches are a reservoir for this pathogen and that once the branches senesce, the pathogen can persist up to 45 days, able to contaminate other plant parts. On inoculated leaves, we observed only a one-point latent infection, without signs of colonization. We also developed a faster protocol to produce pycnidia of the pathogen using autoclaved branches as a substrate, which proved useful for testing alternative compounds to control P. citricarpa. These data may be useful in the search for new effective control measures and their targets. [ABSTRACT FROM AUTHOR]

Sexual reproduction in fungi is controlled by mating type genes, which are located at the MAT locus. In this study, we investigated the structure of this locus in the phytopathogenic fungus Phyllosticta citricarpa, the causal agent of citrus black spot disease. Despite intensive study, its sexual state has never been observed in single-spore culture. Through analysis of the genome sequences of two individual P. citricarpa isolates, the sequence of the DNA lyase gene was identified and, as previously reported in the literature, the mating type genes were located in the 3′ flanking region of this gene. The results suggested that P. citricarpa is heterothallic, owing to the exclusive presence of the MAT1-1 or MAT1-2 gene in individual strains. In order to characterize the MAT locus, we designed primers to amplify this region. P. citricarpa was found to have complete and apparently functional copies of MAT genes, containing α-1 and HMG domains, present in different isolates. In addition to MAT1-2-1 and MAT1-1-1 genes, the MAT1-1-4 gene was located in the 5′ flanking region of the MAT1-1-1 gene and the MAT1-2-5 gene was located in 5′ flanking region of the MAT1-2-1 gene. A multiplex PCR protocol was also developed to differentiate P. citricarpa idiomorphs, which can be used in distribution and incidence studies of mating type strains, in order to determine the occurrence of sexual reproduction and to facility crossing studies. Furthermore, in Brazil, the two idiomorphs occur in a 1:1 ratio, which is expected in sexually reproducing populations. [ABSTRACT FROM AUTHOR]

Citrus black spot (CBS), caused by Guignardia citricarpa, is a fungal disease that was first described in Australia in the 1890s and has since been discovered in Southwest Florida in 2010. The current study evaluated the effects of hot water treatments on mycelial growth of G. citricarpa in vitro and also evaluated postharvest hot-water dips and fungicide treatments on CBS development on 'Valencia' oranges. In vitro exposure to 56 °C for 120 seconds, 59 °C for 60 seconds, or 62 °C for 30 seconds suppressed mycelial growth of all three G. citricarpa isolates by >30%. These treatments did not significantly reduce disease incidence or severity of CBS lesion development on whole 'Valencia' oranges from CBS-infected trees when the fruit already had visible CBS symptoms before treatment. On asymptomatic fruit, while the treatments did not significantly reduce the incidence of CBS lesion development, fruit dipped in 56 °C water for 120 seconds significantly reduced disease severity after 2 weeks of storage compared with the control. None of the treatments caused peel scalding or fruit quality deterioration. Postharvest application of azoxystrobin, imazalil, or thiabendazole significantly reduced CBS disease severity on fruit that were asymptomatic at harvest, but did not affect disease incidence. These fungicides were not effective on fruit harvested later in the season (April), possibly because most lesion expression had already occurred before harvest, with little left to develop after harvest. On fruit showing CBS symptoms at harvest, postharvest fungicide treatments did not significantly affect disease incidence or severity after storage. Heating the fungicide solutions did not significantly improve fungicide effectiveness. These results demonstrated that fungicide azoxystrobin, imazalil, or thiabendazole could reduce CBS severity, but not incidence, on orange fruit that are still asymptomatic at harvest. [ABSTRACT FROM AUTHOR]

Phyllosticta citricarpa is the epidemiological agent of Citrus Black Spot (CBS) disease, which is responsible for large economic losses worldwide. CBS is characterized by the presence of spores (pycnidiospores) in dark lesions of fruit, which are also responsible for short distance dispersal of the disease. The identification of genes involved in asexual reproduction of P. citricarpa can be an alternative for directional disease control. We analyzed a library of mutants obtained through Agrobacterium tumefaciens transformation system, looking for alterations in growth and reproductive structure formation. Two mutant strains were found to have lost the ability to form pycnidia. The flanking T-DNA insertion regions were identified on P. citricarpa genome by using blast analysis and further gene prediction. The predicted genes containing the T-DNA insertions were identified as Spindle Poison Sensitivity Scp3 , Ion Transport protein, and Cullin Binding proteins. The Ion Transport and Cullin Binding proteins are known to be correlated with sexual and asexual reproduction in fungi; however, the exact mechanism by which these proteins act on spore formation in P. citricarpa needs to be better characterized. The Scp3 proteins are suggested here for the first time as being associated with asexual reproduction in fungus. This protein is associated with microtubule formation, and as microtubules play an essential role as spindle machinery for chromosome segregation and cytokinesis, insertions in this gene can lead to abnormal formations, such as that observed here in P. citricarpa . We suggest these genes as new targets for fungicide development and CBS disease control, by iRNA. [ABSTRACT FROM AUTHOR]

The control of citrus black spot (CBS) caused by Phyllosticta citricarpa relies mainly on fungicide sprays. Generally, high and non-standardized spray volumes are adopted and the sprays are based on litre per tree or per hectare. However, the tree canopy volume may vary with age, density and variety, and this is expected to impact on the spray volume and fungicide rates needed for disease control. This study evaluated the efficacy of different fungicide spray volumes and rates for CBS control based on the tree-row-volume (TRV) concept. Two field trials were carried out during three seasons in São Paulo state, Brazil. Trials were set up in commercial orchards of late-maturing ‘Valencia’ sweet orange grown for juice production. In field trial 1, the volumes tested were 125 (standard), 100 (internal runoff point), 75 (intermediate) and 50 (half the internal runoff point) mL of spray mixture/m 3 of the tree canopy. In field trial 2, 100 and 50 mL/m 3 were evaluated. The fungicide rates ranged from 40 to 110 mg of metallic copper/m 3 and from 1.9 to 4.7 mg of pyraclostrobin/m 3 . Untreated control trees (UTC) were kept unsprayed. CBS incidence and severity, premature fruit drop, yield, fungicide deposition and spray coverage were evaluated. All spray volumes tested reduced CBS incidence and severity on fruit at 75–95% and resulted in 1.6–3.0-fold higher yields than the UTC. However, a slight trend of more CBS symptoms and fruit drop, and lower yield was observed for trees treated with 50 mL/m 3 compared to those treated with higher volumes. Spray volume change, from 125 to 75 mL/m 3 , irrespective of fungicide rate correction, led to a 40% reduction of CBS spray costs and water usage and increased the financial return of the control by up to 35%. TRV-based sprays may contribute to sustainable citrus production by reducing costs and environment impacts while maintaining efficient CBS control. [ABSTRACT FROM AUTHOR]

Following a request from the European Commission, the EFSA Panel on Plant Health (PLH) was asked to assess two publications, authored by Magarey et al. and Martínez-Minaya et al. from 2015, with regard to a need to update the EFSA Scientific Opinion from 2014 on the risk of Phyllosticta citricarpa ( Guignardia citricarpa) for the EU territory. The EFSA PLH Panel was also requested to assess any other relevant scientific information published after the finalisation of the EFSA Scientific Opinion. The fungus P. citricarpa (McAlpine) Van der Aa causes the citrus disease citrus black spot (CBS), and is regulated as quarantine organism in Council Directive 2000/29/EC. The Panel assessed the two publications in detail as well as all relevant publications published until 31 March 2016. A comparison with the EFSA PLH Panel () was made, survey data on CBS from South Africa used in Magarey et al. () were evaluated, and the citrus production areas in the EU were characterised and compared with results from Magarey et al. (). Uncertainty and model sensitivity were discussed. It was concluded that the evidence presented in Magarey et al. from 2015 does not require an updating of EFSA PLH Panel (). The conclusion in the Opinion that probability of CBS establishment in the EU is moderately likely is not affected by the paper by Magarey et al. () predicting establishment in some of the EU locations they selected. The high level of uncertainty regarding the probability of establishment is also unchanged by Magarey et al. (). The Panel concluded that Martínez-Minaya et al. (2015) does not provide new evidence requiring an update to EFSA PLH Panel (), principally because it had already been concluded that global climate zones are based on factors and thresholds that are broad and not necessarily representative of those that are critical for the pathogen and its host. [ABSTRACT FROM AUTHOR]

The citrus industry is severely affected by citrus black spot (CBS), a disease caused by the pathogen Phyllosticta citricarpa . This disease causes loss of production, decrease in the market price of the fruit, and reduction in its export to the European Union. Currently, CBS disease is being treated in orchards with various pesticides and fungicides every year. One alternative to CBS disease control without harming the environment is the use of microorganisms for biological control. Diaporthe endophytica and D. terebinthifolii , isolated from the medicinal plants Maytenus ilicifolia and Schinus terebinthifolius have an inhibitory effect against P. citricarpa in vitro and in detached fruits. Moreover, D. endophytica and D. terebinthifolii were transformed by Agrobacterium tumefaciens for in vivo studies. The transformants retained the ability to control of phytopathogenic fungus P. citricarpa after transformation process. Furthermore, D. endophytica and D. terebinthifolii were able to infect and colonize citrus plants, which is confirmed by reisolation of transformants from inoculated and uninoculated leaves. Light microscopic analysis showed fungus mycelium colonizing intercellular region and oil glands of citrus, suggesting that these two new species are capable of colonizing citrus plants, in addition to controlling the pathogen P. citricarpa . [ABSTRACT FROM AUTHOR]

Following a request from the European Commission, the EFSA Panel on Plant Health (EFSA PLH Panel) was asked to react to a document entitled “Comments on the European Union Food Safety Authority’s Pest Risk Assessment for Phyllosticta citricarpa”, authored by Hattingh et al., which was posted online in August 2014 on the website of Citrus Research International (Pty) Ltd, South Africa. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa (McAlpine) Van der Aa, is a fruit-blemishing and leaf-spotting disease affecting citrus. P. citricarpa is not known to occur in the EU territory and is regulated as a quarantine organism in citrus (Council Directive 2000/29/EC). The Panel assessed the comments by Hattingh et al. in the light of the content of the EFSA PLH Panel Scientific Opinion on CBS and the EFSA report detailing responses to comments received during the public consultation on the draft opinion. The Panel stands by the EFSA PLH Panel Scientific Opinion on CBS and considers that the comments by Hattingh et al. have been thoroughly addressed in the EFSA report on the public consultation on the EFSA PLH Panel Scientific Opinion on CBS. A detailed point by point reply to the comments by Hattingh et al. is provided in an Appendix of this Panel statement. Since September 2014, EFSA has written to the lead author of the comments trying to engage in a scientific dialogue concerning the sources of uncertainty related to the risks posed by P. citricarpa to plant health in the EU, so as to identify ways to reduce such uncertainties (e.g. with further research and/or data exchange). The EFSA PLH Panel also remains open to such constructive dialogue in the future.

The Panel conducted a risk assessment of Phyllosticta citricarpa for the EU. P. citricarpa causes citrus black spot (CBS) and is absent from the EU. Under the scenario of absence of specific risk reduction options against P. citricarpa, the risk of entry of P. citricarpa was rated as likely for citrus plants for planting and citrus fruit with leaves, moderately likely for citrus fruit without leaves, unlikely for citrus leaves for cooking and very unlikely for Tahiti lime fruit without leaves. Establishment was rated as moderately likely because susceptible hosts are widely available and environmental conditions in many EU citrus-growing areas are suitable (with high uncertainty) for P. citricarpa ascospore production, dispersal and infection. Current fungicide treatments will not prevent establishment. Environmental favourability is increased by the use of sprinkler and micro-sprinkler irrigation in some EU citrus-growing locations. Spread with trade was rated as moderately likely. Model results indicate that CBS epidemics are most likely to develop in EU citrus-growing areas in late summer to early autumn and in some locations also in late spring to early summer. CBS is expected to affect mainly lemons and late-maturing sweet orange and mandarin varieties, with moderate negative consequences for the production of fresh fruit, but with environmental impact of additional fungicide treatments. Negative consequences would be minor for early-maturing citrus varieties and minimal for citrus for processing. Uncertainty concerning the consequences is high, mainly because of the lack of data on critical climate response parameters for the pathogen but also because information on impact in areas at the limits of the current distribution is scarce. Since eradication and containment are difficult, phytosanitary measures should focus on preventing entry. Current phytosanitary measures are evaluated to be effective, with the exception of pest-free production sites.

Following a request from the European Commission, the EFSA Panel on Plant Health (EFSA PLH Panel) was asked to react to a document entitled ' Comments on the European Union Food Safety Authority's Pest Risk Assessment for Phyllosticta citricarpa', authored by Hattingh et al., which was posted online in August 2014 on the website of Citrus Research International (Pty) Ltd, South Africa. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa (McAlpine) Van der Aa, is a fruit-blemishing and leaf-spotting disease affecting citrus. P. citricarpa is not known to occur in the EU territory and is regulated as a quarantine organism in citrus (Council Directive 2000/29/EC). The Panel assessed the comments by Hattingh et al. in the light of the content of the EFSA PLH Panel Scientific Opinion on CBS and the EFSA report detailing responses to comments received during the public consultation on the draft opinion. The Panel stands by the EFSA PLH Panel Scientific Opinion on CBS and considers that the comments by Hattingh et al. have been thoroughly addressed in the EFSA report on the public consultation on the EFSA PLH Panel Scientific Opinion on CBS. A detailed point by point reply to the comments by Hattingh et al. is provided in an Appendix of this Panel statement. Since September 2014, EFSA has written to the lead author of the comments trying to engage in a scientific dialogue concerning the sources of uncertainty related to the risks posed by P. citricarpa to plant health in the EU, so as to identify ways to reduce such uncertainties (e.g. with further research and/or data exchange). The EFSA PLH Panel also remains open to such constructive dialogue in the future. [ABSTRACT FROM AUTHOR]