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Wilting, leaf shedding and defoliation on a young lemon tree affected by mal secco (courtesy S.O. Cacciola, G. Magnano di San Lio, A. Pane).
Contexts in source publication
Context 1
... mal secco, an Italian name meaning "dry disease", is a vascular wilt disease (Figure 1) caused by the mitosporic fungus Plenodomus tracheiphilus (P. tracheiphilus), formerly Phoma tracheiphila. ...
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... the last years, an epidemic outbreak of a foliar disease closely resembling greasy spot has been observed in some citrus-growing areas of western Sicily (Italy). Symptoms appear on mature leaves and range from those typical of greasy spot (Figures 9 and 10) to black dots. Premature leaf drop occurs and causes heavy defoliation of the tree. ...
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... produced by basidiomata germinate with relative humidity over 90% and are dispersed by wind. Usually, basidiomata (Figure 11) emerge from the bark after the wood of trunk or branches has been extensively colonized by the fungus (Figure 12). In Southern Italy, the analysis of F. mediterranea internal transcribed spacer (ITS) sequences revealed a high level of genetic variability, with both homozygous and heterozygous genotypes. ...
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... produced by basidiomata germinate with relative humidity over 90% and are dispersed by wind. Usually, basidiomata (Figure 11) emerge from the bark after the wood of trunk or branches has been extensively colonized by the fungus (Figure 12). In Southern Italy, the analysis of F. mediterranea internal transcribed spacer (ITS) sequences revealed a high level of genetic variability, with both homozygous and heterozygous genotypes. ...
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... species attack citrus plants at all stages and may infect all parts of the tree, including roots, stem, branches, twigs, leaves and fruits. There are several forms (facies) of Phytophthora diseases including root rot, foot rot ( Figure 13) (also known as Phytophthora gummosis, trunk gummosis or collar rot), fruit brown rot (Figure 14), twig and leaf dieback (often indicated collectively as canopy blight) and rot of seedlings (better known as damping off of seedlings). Trunk gummosis and root rot are the most serious facies of this group of diseases, and after the pandemic outbreak of the nineteenth century and the consequent widespread use of resistant rootstocks, they are regarded as endemic diseases in all citrus-growing areas of the world. ...
Context 6
... species attack citrus plants at all stages and may infect all parts of the tree, including roots, stem, branches, twigs, leaves and fruits. There are several forms (facies) of Phytophthora diseases including root rot, foot rot ( Figure 13) (also known as Phytophthora gummosis, trunk gummosis or collar rot), fruit brown rot (Figure 14), twig and leaf dieback (often indicated collectively as canopy blight) and rot of seedlings (better known as damping off of seedlings). Trunk gummosis and root rot are the most serious facies of this group of diseases, and after the pandemic outbreak of the nineteenth century and the consequent widespread use of resistant rootstocks, they are regarded as endemic diseases in all citrus-growing areas of the world. ...
Citations
... In Tunisia, citrus is economically important (Boughalleb-M'Hamdi et al., 2020). However, citrus production is continuously threatened by many pests and diseases, which cause significant economic losses and social impacts (Khanchouch et al., 2017). ...
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.
... In the context of highly competitive markets, a number of factors such as technical management, pedoclimatic conditions, and rootstock traits, are partially involved in the significant discrepancy in citrus fruit yield among the leading producing countries [6,7,8]. Moreover, citrus crops are vulnerable to many threats and fungal attacks that constitute a serious phytosanitary challenge facing citrus fruit production [9,10]. Among the most widespread citrus diseases in Morocco are citrus phytophthora gummosis caused by Phytophthora spp., citrus Phytophthora root rot, anthracnose, and citrus brown rot [7,11,12]. ...
... The Mal-secco is a highly destructive disease of Citrus in fungus, which colonizes the vascular tissues of plants, leading to veinal chlorosis, wilt, and water stress. The presence of oxidative stress inducers and membrane transporters in fungus also facilitates the interaction with the host (Khanchouch et al. 2017). Fungal disease infection has reported toxic glycopeptides being involved in pathogenesis (Nachmias et al. 1977). ...
Etrog-citron is a variety of Citrus medica (var. ethrog Engl) belonging to the family Rutaceae. etrog citron is considered the father of citrus fruits and it has deeply rooted in the Hebrew religion which has been used by Jews in their religious ritual “Sukkot” since ancient times. It is cultivated majorly in the Mediterranean regions, America, China, and a few parts of India. Grafting and seed germination are the major propagation techniques for cultivation. Viroids and viruses are the major infectious agents causing diseases like yellow vein disease, dwarfing, leaf curling, and other diseases which lead to decrease in plant yield. Etrog fruit is rich in fats, sugars, fibers, macro-nutrients (vitamin C, calcium, potassium, magnesium, iron, phosphorous, thiamine, etc.,) and micro-nutrients (riboflavin, niacin, copper, manganese, zinc, manganese, chromium, etc.,). The chemical constituents of fruit are influenced by variable factors such as genotype, climatic conditions, and harvesting practices. The fruits are rich in essential oil (terpenes), carotenoids, alkaloids, flavonoids, pectin, mucilage, sterols, glycoside, and other phytoconstituents. In addition, leaves consist of volatile oil, flavonoids, steroids, and glycosides. Ethno-medicinal uses of this plant are well exploited in traditional medicinal systems like Jewish medicine, Ayurveda, Chinese traditional medicine, etc., to treat nausea, excessive thirst, skin disease, acne, child labor, and other general health issues. Leaves and fruits are rich in bioactive constituents and show immunomodulatory, anti-oxidant, anti-inflammatory, anti-tumor, laxative, anti-hyperglycemic, and anti-microbial activities. The fruits of this plant are important to the Jewish Sukkot traditional festival and the highest quality of the fruit is highly valued. Apart from the ritual, the fruits are used to extract volatile oil for the perfumery and food flavouring industry. The fruits are used for cooking traditional dishes all over the world. Citrus medica (var. ethrog Engl) is used in making alcoholic beverages, syrup, candied peels, jams, carbonated drinks, marmalade, and other value-added products. Pectin obtained from the fruits can be used for food thickener, baking, jellies, low-calorie foods, and various pharmaceutical applications. The present chapter focused on the importance of etrog fruit in the traditional medicine system, phytochemical constituents, nutritional and nutraceutical values, pharmacological and biological activities, and commercial values. The current chapter will give comprehensive and multi-faceted information on Citrus medica (var. etrog) and its application in various fields.
... This occurs in nonoptimal disturbed environments (Slippers and Wingfield 2007). Abiotic factors such as severe sunburn, drought, and freezing predispose plants, including citrus, to xylem dysfunction, which results in branch canker and die-back (Raimondo et al. 2010;Khanchouch et al. 2017;Aloi et al. 2021). In dogwoods (Cornus florida), plant stress has been demonstrated to be a crucial factor in triggering the pathogenic behavior of L. theobromae, and this was corroborated by the failure of artificial inoculations in pathogenicity trials (Mullen et al. 1991). ...
Lasiodiplodia species commonly thrive as endophytes, saprobes, and plant pathogens in tropical and subtropical regions. Association of Lasiodiplodia species causing stem rot in dragon fruit in the coastal belt of Odisha, eastern India, has been illustrated here. The stem rot disease was characterized by yellowing of the stem, followed by softening of the stem tissues with fungal fructifications of the pathogen in the affected tissues. On the basis of macro- and micromorphological characteristics, the four fungal isolates recovered from diseased stems were identified initially as Lasiodiplodia species. By comparing DNA sequences within the NCBI GenBank database as well as performing a multigene phylogenetic analysis involving the internal transcribed spacer region (ITS-rDNA), β-tubulin (β-tub), and elongation factor-alpha (EF1-α) genes, the identity of Lasiodiplodia isolates was determined. The isolate CHES-21-DFCA was identified as Lasiodiplodia iraniensis (syn: L. iranensis) and the remaining three isolates, namely CHES-22-DFCA-1, CHES-22-DFCA-2, and CHES-22-DFCA-3, as L. theobromae. Although pathogenicity studies confirmed both L. iraniensis and L. theobromae were responsible for stem rot in dragon fruit, L. iraniensis was more virulent than L. theobromae. This study established the association of Lasiodiplodia species with stem rot in dragon fruit using a polyphasic approach. Further investigations are required, particularly related to on host–pathogen–weather interaction and spatiotemporal distribution across the major dragon fruit–growing areas of the country to formulate prospective disease management strategies. This is the first report on these two species of Lasiodiplodia inflicting stem rot in Hylocereus species in India.
... Citrus (Citrus spp. L.) is among the most widely grown fruit trees in the world, and have high nutritional, medicinal, and economic value (Khanchouch et al. 2017;Mvondo-She et al. 2021). Citrus fruits, rich in vitamins and minerals include many species such as orange (Citrus sinensis L.), mandarin (C. ...
... Plant diseases are one of the most important limiting biotic factors in citrus production (Soares et al. 2020). Several species of Fusarium, Phytophthora, Colletotrichum, Botrytspharea, and Penicillium are known as the major important pathogens causing diseases on roots, stems, leaves, shoots, and fruits (Khanchouch et al. 2017;Jaouad et al. 2020). Bacterial diseases pose a constant threat to citrus production and cause significant economic impacts in all growing regions of the world. ...
Citrus (Citrus spp. L.), which has high nutritional and economic value, is one of the most commonly grown fruits in Turkey. In spring 2020, large aerial galls (tumors) were observed on trunks and main branches of mandarin (Citrus reticulata cv. Satsuma) and lemon (Citrus limon cv. Kutdiken) trees grafted to sour orange (Citrus aurantium L.) in commercial citrus orchards in Hatay and Mersin provinces of Turkey. Disease incidence was 0.2–1.0% in the orchards inspected. Six bacterial isolates were obtained from young tumors on King's B (KB) medium. Several biochemical and morphological characteristics of all isolates were consistent with the description of the tumorigenic bacterium Agrobacterium tumefaciens (= Agrobacterium biovar 1). Identification of these isolates was confirmed by comparison with reference isolates of Agrobacterium tumefaciens (Syn. Rhizobium radiobacter) using MALDI-TOF MS analysis. The pathogenicity of the isolates was confirmed on carrot slice and stems from 6-month-old Kalanchoe plants and 2-year-old mandarin (cv. Satsuma) saplings. For molecular identification, the 16S rRNA and virD2 genes were amplified with primer pairs 27F/1492R and VirD2A/VirD2C, respectively and the PCR products were sequenced for representative isolates (CAt21, CAt27). The partial sequences of 16S rRNA (accessions numbers MZ708735 and MZ708734) and VirD2A/VirD2C of the representative isolates (CAt21, CAt27) showed 100% nucleotide identity to the A. tumefaciens isolates available in GenBank. According to symptoms, biochemical characteristics, pathogenicity test and molecular analyses, the causative agent of the disease was identified as Agrobacterium tumefaciens (= Agrobacterium biovar 1). To our knowledge, this is the first report of Agrobacterium tumefaciens (= Agrobacterium biovar 1) on citrus in Turkey.
... The Colletotrichum acutatum (C. acutatum) species complex is known as especially destructive on fruits such as strawberry [5][6][7] , apple [8][9][10][11] , citrus [12][13][14][15][16] , olive [17][18][19][20][21] , cranberry [22,23] , blueberry [24][25][26][27] and peach [28] . ...
Objective: Anthracnose is a disease caused by Colletotrichum species and is a significant disease in the strawberry crop. This study aims to identify at the level of species Colletotrichum spp. isolates collected from symptomatic strawberry plants in Tucumán, Argentina's second most important strawberry production area. Methods: 45 isolates of Colletotrichum were collected and characterized. Morphological characterization was conducted by analyzing fungal cultural characteristics, the growth rate in potato dextrose agar plates, conidial morphology and size, and sexual state. Phytopathological characterization was carried out by plant-pathogen interactions under controlled conditions in infection chambers. Molecular characterization was performed by polymerase chain reaction analysis of regions of amplified mitochondrial small rRNA genes. Results: Preliminary morphological characterization led to three distinctive groups, based on conidial shape and size, and colony type, colour, and growth, whereas the phytopathological characterization, led to two distinct groups based on the severity of symptoms, virulence, and host specificity. Molecular analyses confirmed the identity of three isolates representing each of the microbiological groups (i.e., isolate F7 of Colletotrichum acutatum (C. acutatum), isolate L9 of C. acutatum, isolate M11 of C. acutatum), demonstrating that they correspond to C. acutatum species. Based on the analysis of ribosomal DNA internal transcribed spacers sequences, and using specific microsatellites, we found a high genetic variability among all C. acutatum sequences. Implications of these results, as well as biological products commercially available and research advancing the field of biological control agents, were also discussed. Conclusion: This is the latest study to report with confidence that the species of Colletotrichum present in Tucumán, Argentina corresponds to C. acutatum, and such species are genetically diverse.
... For example, in citrus fruits, diseases such as melanin, canker, and scab often occur after rain. As a result, citrus production and cultivation cause significant economic losses in all growing regions of the world and continue to be threatened by many factors, such as pathogens and pests [4]. The state of Florida in the USA spent USD 1 billion on the eradication of citrus pests for ten years from 1995 to 2005, and the state of Queensland in Australia spent AUD 18.5 million for the same goal [5]. ...
Plant diseases are a major cause of reduction in agricultural output, which leads to severe economic losses and unstable food supply. The citrus plant is an economically important fruit crop grown and produced worldwide. However, citrus plants are easily affected by various factors, such as climate change, pests, and diseases, resulting in reduced yield and quality. Advances in computer vision in recent years have been widely used for plant disease detection and classification, providing opportunities for early disease detection, and resulting in improvements in agriculture. Particularly, the early and accurate detection of citrus diseases, which are vulnerable to pests, is very important to prevent the spread of pests and reduce crop damage. Research on citrus pest disease is ongoing, but it is difficult to apply research results to cultivation owing to a lack of datasets for research and limited types of pests. In this study, we built a dataset by self-collecting a total of 20,000 citrus pest images, including fruits and leaves, from actual cultivation sites. The constructed dataset was trained, verified, and tested using a model that had undergone five transfer learning steps. All models used in the experiment had an average accuracy of 97% or more and an average f1 score of 96% or more. We built a web application server using the EfficientNet-b0 model, which exhibited the best performance among the five learning models. The built web application tested citrus pest disease using image samples collected from websites other than the self-collected image samples and prepared data, and both samples correctly classified the disease. The citrus pest automatic diagnosis web system using the model proposed in this study plays a useful auxiliary role in recognizing and classifying citrus diseases. This can, in turn, help improve the overall quality of citrus fruits.
... Citrus is among the top 10 economically important crops in terms of total global fruit yield and ranks first in international fruit trade in terms of value. Although citrus is native to East Asia, currently, it is grown all over the world particularly in tropical, subtropical and Mediterranean climatic regions on more than 10 million hectares of land (Khanchouch et al., 2017). Presently, it was found that some of the Mediterranean countries such as Greece, Italy, Spain, Tunisia, Turkey, Australia, California, Florida and South Africa are the leading producers for the international fresh market (Vitale et al., 2021). ...
Aim: The main aim of the present study was to develop nanotechnology-based
solutions
for the management of a fungus, Phytophthora parasitica causing gummosis in
citrus.
Methods and Results: Biogenic copper nanoparticles (CuONPs) were synthesized
using two different biocontrol agents, Pseudomonas fluorescens and Trichoderma
viride and characterized using different analytical techniques. Furthermore, in vitro
(at the concentrations of 10, 15, 30, 50, 70, 100 and 150 mg/L) and in vivo (at the concentration
of 100 mg/L) activities of these nanoparticles were evaluated for their antifungal
efficacy against P. parasitica. The results obtained confirmed the synthesis
of irregular-shaped
CuONPs having a size in the range 40–100
nm in case of P. fluorescens,
whereas, spherical CuONPs in the size range 20–80
were recorded in case of T.
viride. As far as the in vitro antifungal efficacies of both these CuONPs is concerned,
the maximum percent growth inhibition was observed in case of CuONPs synthesized
from T. viride compared to CuONPs from P. fluorescens. However, in case of
in vivo antifungal efficacies, CuONPs synthesized from T. viride showed the activity
significantly higher than the conventionally used Bordeaux mixture.
Conclusions: It can be concluded that biosynthesized CuONPs can be effectively
used as a potential fungicide against P. parasitica.
Significance and Impact of the Study: The application of nanoparticles having
antifungal activities can be used as alternative fungicides to the conventional chemical
fungicides. It has the potential to revolutionize the existing management strategies
available for plant pathogenic fungi.
... Citrus is among the top 10 economically important crops in terms of total global fruit yield and ranks first in international fruit trade in terms of value. Although citrus is native to East Asia, currently, it is grown all over the world particularly in tropical, subtropical and Mediterranean climatic regions on more than 10 million hectares of land (Khanchouch et al., 2017). Presently, it was found that some of the Mediterranean countries such as Greece, Italy, Spain, Tunisia, Turkey, Australia, California, Florida and South Africa are the leading producers for the international fresh market (Vitale et al., 2021). ...
Aim:
The main aim of the present study is to develop nanotechnology-based solutions for the management of a fungus, Phytophthora parasitica causing gummosis in citrus.
Methods and results:
Biogenic copper nanoparticles (CuONPs) were synthesized using two different biocontrol agents, Pseudomonas fluorescens and Trichoderma viride and characterized using different analytical techniques. Further, in vitro (at the concentrations of 10 mg/L, 15 mg/L, 30 mg/L, 50 mg/L, 70 mg/L, 100 mg/L and 150 mg/L) and in vivo (at the concentration of 100 mg/L) activities of these nanoparticles were evaluated for their antifungal efficacy against P. parasitica. The results obtained confirmed the synthesis of irregular shaped CuONPs having a size in the range of 40-100 nm in case of P. fluorescens, whereas, spherical CuONPs in the size range of 20-80 were recorded in case of T. viride. As far as the in vitro antifungal efficacies of both these CuONPs is concerned, the maximum percent growth inhibition was observed in case of CuONPs synthesized from T. viride compared to CuONPs from P. fluorescens. However, in case of in vivo antifungal efficacies, CuONPs synthesized from T. viride showed the activity significantly higher than the conventionally used Bordeaux mixture.
Conclusions:
It can be concluded that biosynthesized CuONPs can be effectively used as a potential fungicide against P. parasitica.
Significance and impact of the study:
The application of nanoparticles having antifungal activities can be used as alternative fungicides to the conventional chemical fungicides. It has the potential to revolutionize the existing management strategies available for plant pathogenic fungi.
... Fungicides, including azoles, are commonly applied at times to both secure yield and market value and reduce postharvest losses. The most important fungal diseases that attack citrus trees are dieback/mal secco of citrus (Plenodomus tracheiphilus), postbloom fruit drop (Colletotrichum spp.), Alternaria brown spot (Alternaria spp.), citrus scab (Elsinoe fawcettii), greasy spot (Zasmidium citri-griseum) and melanoses of citrus (Diaporthe citri) (Timmer et al., 2004;Khanchouch et al., 2017). ...
Plant pathogens cause significant damage to plant products, compromising both quantities and quality. Even though many elements of agricultural practices are an integral part of reducing disease attacks, modern agriculture is still highly reliant on fungicides to guarantee high yields and product quality. The azoles, 14-alpha demethylase inhibitors, have been the fungicide class used most widely to control fungal plant diseases for more than four decades. More than 25 different azoles have been developed for the control of plant diseases in crops and the group has a world market value share of 20-25%. Azoles have proven to provide long-lasting control of many target plant pathogens and are categorized to have moderate risk for developing fungicide resistance. Field performances against many fungal pathogens have correspondingly been stable or only moderately reduced over time. Hence azoles are still, to date, considered the backbone in many control strategies and widely used as solo fungicides or as mixing partners with other fungicide groups, broadening the control spectrum as well as minimizing the overall risk of resistance development. This review describes the historic perspective of azoles, their market shares and importance for production of major crops like cereals, rice, oilseed rape, sugar beet, banana, citrus, and soybeans. In addition, information regarding use in amenity grass, in the wood preservation industry and as plant growth regulators are described. At the end of the review azoles are discussed in a wider context including future threats following stricter requirements for registration and potential impact on human health.
