First Report of Sour Rot of California Peaches and Nectarines Caused by Yeasts

In early July 2001, samples of nectarine and peach fruit were brought from orchards in northern Tulare County or from packinghouses to our laboratory for diagnosis of an unusual decay. When the decay lesions originated close to the stylar end, leaking juice streamed from it. When the decay lesion was on the stem end of the fruit and touched the packing box, it developed a decay consisting of a ring of 0.5 to 2.0 cm (inner diameter) and 1.0 to 3.0 cm (outer diameter). The leaking juice dissolved the cuticle, epidermis, and some of the flesh, creating distinct furrows in the tissue. Samples with similar decay lesions were examined in 2001, 2002, and 2003. In each year, isolations from these fruit consistently yielded two or three different yeasts that were identified as Geotrichum candidum Link, Issatchenkia scutulata (Phaff et al.) Kurtzman et al., and Kloeckera apiculata (Reess emend. Klocker) Janke. All three yeasts were isolated from most of the samples, although sometimes, different combinations of two of the yeasts recovered. To complete Koch's postulates, each yeast was single spored and cultured on acidified potato dextrose agar at 25°C to prepare a dense (108) cell suspension. Eight, mature, ‘Elegant Lady’ peach fruit were surface disinfested in 0.1% sodium hypochlorite for 3 min, allowed to dry, and wounded once with a sterile nail (3 × 5 mm) on the fruit cheek. A 50-µl drop of the cell suspension was placed in each wound, and the peaches were incubated in containers with >95% relative humidity at 27°C. Fruit inoculated similarly with a 50-µl drop of sterile water served as controls. In 2001, two containers containing eight fruit each were used for each yeast, and lesions started developing within 1 week after inoculation. The diameter of the decay lesion was measured after 10 days of incubation of the fruit. The diameter of decay lesions ranged from 21 to 68 mm for G. candidum, 30 to 55 mm for I. scutulata, and 9 to 39 mm for K. apiculata inoculations. The inoculation experiment was repeated with two containers of eight ‘Red Glo’ nectarine fruit per treatment yeast, under the same conditions as described above. Organisms recovered from the decay lesions were the same yeasts used for inoculating the peaches or nectarines. All three yeasts caused similar decay lesions in peaches, and the leaking effect was reproduced in both types of fruit. Symptoms were similar to those observed on fruit samples brought to our laboratory. Control fruit did not develop the characteristic decay lesions, although brown rot caused by Monilinia fructicola developed on a few of the control fruit. We concluded that each isolated yeast had the capacity to cause sour rot decay on stone fruit. From samples and reports, the disease has been found on ‘Red Glo’, ‘Ruby Diamond’, ‘Zee Grand’, ‘Spring Bright’, and ‘Honey Blaze’ nectarines and ‘Elegant Lady’ and ‘Fire Red’ peaches. G. candidum was isolated from peaches and other fruit in California and incited rot of ‘Paloro’ peach in 1960 (2) and caused postharvest sour rot of peaches originating from Georgia, Pennsylvania, New Jersey, and North Carolina (1). However, to our knowledge, this is the first report of G. candidum, I. scutulata, or K. apiculata causing sour rot of commercial peaches and nectarines in the field and postharvest situations in California. References: (1) C. L. Burton and W. R. Wright. Plant Dis. Rep. 53:580, 1969. (2) E. E. Butler. Phytopathology 50:665, 1960.

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First Report of Pepper Fruit Rot Caused by Fusarium concentricum in China

Plant Disease ◽

10.1094/pdis-03-13-0325-pdn ◽

2013 ◽

Vol 97 (12) ◽

pp. 1657-1657 ◽

Cited By ~ 6

Author(s):

J. H. Wang ◽

Z. H. Feng ◽

Z. Han ◽

S. Q. Song ◽

S. H. Lin ◽

...

Keyword(s):

Fusarium Species ◽

Fruit Rot ◽

Post Inoculation ◽

Distilled Water ◽

Conidial Suspension ◽

Average Growth ◽

First Report ◽

Control Fruit ◽

Pepper Fruit ◽

Fruit Samples

Pepper (Capsicum annuum L.) is an important vegetable crop worldwide. Some Fusarium species can cause pepper fruit rot, leading to significant yield losses of pepper production and, for some Fusarium species, potential risk of mycotoxin contamination. A total of 106 diseased pepper fruit samples were collected from various pepper cultivars from seven provinces (Gansu, Hainan, Heilongjiang, Hunan, Shandong, Shanghai, and Zhejiang) in China during the 2012 growing season, where pepper production occurs on approximately 25,000 ha. Pepper fruit rot symptom incidence ranged from 5 to 20% in individual fields. Symptomatic fruit tissue was surface-sterilized in 0.1% HgCl2 for 1 min, dipped in 70% ethanol for 30 s, then rinsed in sterilized distilled water three times, dried, and plated in 90 mm diameter petri dishes containing potato dextrose agar (PDA). After incubation for 5 days at 28°C in the dark, putative Fusarium colonies were purified by single-sporing. Forty-three Fusarium strains were isolated and identified to species as described previously (1,2). Morphological characteristics of one strain were identical to those of F. concentricum. Aerial mycelium was reddish-white with an average growth rate of 4.2 to 4.3 mm/day at 25°C in the dark on PDA. Pigments in the agar were formed in alternating red and orange concentric rings. Microconidia were 0- to 1-septate, mostly 0-septate, and oval, obovoid to allantoid. Macroconidia were relatively slender with no significant curvature, 3- to 5-septate, with a beaked apical cell and a foot-shaped basal cell. To confirm the species identity, the partial TEF gene sequence (646 bp) was amplified and sequenced (GenBank Accession No. KC816735). A BLASTn search with TEF gene sequences in NCBI and the Fusarium ID databases revealed 99.7 and 100% sequence identity, respectively, to known TEF sequences of F. concentricum. Thus, both morphological and molecular criteria supported identification of the strain as F. concentricum. This strain was deposited as Accession MUCL 54697 (http://bccm.belspo.be/about/mucl.php). Pathogenicity of the strain was confirmed by inoculating 10 wounded, mature pepper fruits that had been harvested 70 days after planting the cultivar Zhongjiao-5 with a conidial suspension (1 × 106 spores/ml), as described previously (3). A control treatment consisted of inoculating 10 pepper fruits of the same cultivar with sterilized distilled water. The fruit were incubated at 25°C in a moist chamber, and the experiment was repeated independently in triplicate. Initially, green to dark brown lesions were observed on the outer surface of inoculated fruit. Typical soft-rot symptoms and lesions were observed on the inner wall when the fruit were cut open 10 days post-inoculation. Some infected seeds in the fruits were grayish-black and covered by mycelium, similar to the original fruit symptoms observed at the sampling sites. The control fruit remained healthy after 10 days of incubation. The same fungus was isolated from the inoculated infected fruit using the method described above, but no fungal growth was observed from the control fruit. To our knowledge, this is the first report of F. concentricum causing a pepper fruit rot. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (2) K. O'Donnell et al. Proc. Nat. Acad. Sci. USA 95:2044, 1998. (3) Y. Yang et al. 2011. Int. J. Food Microbiol. 151:150, 2011.

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First Report of Brown Rot Caused by Monilia polystroma on Apple in Serbia

Plant Disease ◽

10.1094/pdis-07-12-0670-pdn ◽

2013 ◽

Vol 97 (1) ◽

pp. 145-145 ◽

Cited By ~ 9

Author(s):

M. Vasić ◽

N. Duduk ◽

M. S. Ivanović

Keyword(s):

Brown Rot ◽

Apple Fruit ◽

Molecular Characteristics ◽

Its2 Region ◽

Morphological Identification ◽

Japanese Species ◽

First Report ◽

Control Fruit ◽

Molecular Features ◽

Monilia Polystroma

Monilia polystroma van Leeuwen is a new Japanese species, similar to M. fructigena but distinguishable based on morphological and molecular characteristics (3). After its first discovery on apple in Japan, occurance of M. polystroma in Europe has been reported in Hungary, the Czech Republic, and Switzerland (2,3,4). In October 2011, during a survey for apple fungal pathogens in the Bela Crkva district, 15 apple fruit (Malus domestica Borkh.) cv. Golden Delicious were collected. Two isolates of Monilinia polystroma were obtained from apple fruit showing brown rot, covered with small yellowish sporodohia. The pathogen was identified as M. polystroma based on morphological and molecular features (1,3). Upon isolation, colonies cultivated on PDA were white to grayish and the mycelium grew 8.85 mm per day at 22 ± 1°C in 12-h light/12-h dark regime. After 6 to 8 days of incubation, black stromatal plates were observed on the reverse sides of the inoculated petri dishes. Conidia were one-celled, limoniform, hyaline, 14.7 to 21.88 μm (16.2 mean) × 7.85 to 12.92 μm (10.8 mean), and were produced in branched monilioid chains on inoculated apple fruit. Morphological identification was confirmed by PCR (1) using genomic DNA extracted from the mycelium of pure cultures, and amplified products of 425 bp in length, specific for M. polystroma were amplified as expected with primers MO368-5 and MO368-8R. For one isolate, the ribosomal ITS1-5.8S-ITS2 region was obtained, using primers ITS1 and ITS4, and deposited in GenBank (Accession No JX315717). The sequence was 498 bp in length and showed 100% identity with sequences deposited for M. polystroma in NCBI GenBank (JN128835, AM937114, GU067539). Pathogenicity was confirmed by wound-inoculating five surface-sterilized, mature apple fruit with mycelium plugs (5 mm in diameter) of both isolates grown on PDA. Control fruit were inoculated with sterile PDA plugs. After 3 days of incubation in plastic containers, under high humidity (RH 90 to 95%) at 22 ± 1°C, typical symptoms of brown rot developed on inoculated fruit, while control fruit remained symptomless. Isolates recovered from symptomatic fruit showed the same morphological and molecular characteristics as original isolates. To the best of our knowledge, this is the first report of M. polystroma in Serbia. Further studies are necessary to estimate the economic importance and geographic distribution of this organism in Serbia. References: (1) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (2) M. Hilber-Bodmer et al. Plant Dis. 96: 146, 2012. (3) G. C. M. van Leeuwen et al. Mycol. Res. 106: 444, 2002. (4) OEPP/EPPO Reporting Service. Retrieved from http://archives.eppo.int/EPPOReporting/2011/Rse-1106.pdf

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First Report of Anthracnose on Peach Fruit Caused by Colletotrichum truncatum in South Carolina

Plant Disease ◽

10.1094/pdis-12-13-1215-pdn ◽

2014 ◽

Vol 98 (8) ◽

pp. 1154-1154 ◽

Cited By ~ 4

Author(s):

A. Grabke ◽

M. Williamson ◽

G. W. Henderson ◽

G. Schnabel

Keyword(s):

South Carolina ◽

Causal Agent ◽

Distilled Water ◽

Conidial Suspension ◽

Sterile Water ◽

Colletotrichum Truncatum ◽

Peach Fruit ◽

First Report ◽

Anthracnose Disease ◽

Control Fruit

In July 2013, two diseased peach fruit (Prunus persica (L.) Stokes) of the cv. Sweet Dream were collected from a commercial orchard in Ridge Springs, South Carolina. Affected peaches were at or near maturity and symptoms resembled anthracnose disease caused by Colletotrichum spp. with circular sunken tan to brown lesions that were firm in touch, and had wrinkled concentric rings. The center of the lesion was covered with black acervuli containing setae. To isolate the causal agent, the two symptomatic fruit were surface-sterilized in 10% bleach for 2 min and rinsed with sterile distilled water. Lesions were cut in half, and necrotic tissue from the inside of the fruit was placed on acidified potato dextrose agar (APDA). Flat colonies covered with olive-gray to iron-gray acervuli developed on APDA incubated at 22°C with a 12-h cycle of fluorescent light and darkness. Morphology of acervuli, setae (avg. 90 to 160 μm), conidiophores (up to 90 um long), and conidia (avg. 22 × 3.8 μm) of single spore isolates were consistent with descriptions of Colletotrichum truncatum (Schwein.) Andrus & W.D. Moore (3), a causal agent of anthracnose disease. Genomic DNA was extracted from isolate Ct_RR13_1 using the MasterPure Yeast DNA Purification Kit (Epicentre, Madison, WI). The ribosomal ITS1-5.8S-ITS2 region and a partial sequence of the actin gene were amplified with primer pair ITS1 and ITS4 (4), and primer pair ACT-512F and ACT-783A (2), respectively. A multilocus sequence identification in Q-bank Fungi revealed a 100% similarity with C. truncatum (1). The C. truncatum sequences from the peach isolate were submitted to GenBank (accessions KF906258 and KF906259). Pathogenicity of isolate Ct_RR13_1 was confirmed by inoculating five mature but still firm peach fruits with a conidial suspension of C. truncatum. Peaches were washed with soap and water, surface-disinfected for 2 min with 10% bleach, rinsed with sterile distilled water, and air dried. Dried fruit were stabbed at three equidistant points, each about 2 cm apart, to a depth of 9.5 mm using a sterile 26G3/8 beveled needle (Becton Dickinson & Co., Rutherford, NJ). For inoculation, a 30-μl droplet of conidia suspension prepared in distilled, sterile water (1 to 2 × 104 spores/ml) was placed on each wound; control fruit received sterile water without conidia. Fruit were incubated at 22°C for 2 days at 100% humidity and another 12 days at 70% humidity. Inoculated fruit developed anthracnose symptoms with sporulating areas as described above and the fungus was re-isolated. All control fruit remained healthy. C. truncatum has a wide host range, including legumes and solanaceous plants of the tropics, and is especially common in the Fabaceae family. Its occurrence in a commercial peach orchard is worrisome because control measures may need to be developed that are different from those developed for endemic species, i.e. C. acutatum and C. gloeoporioides, due to differences in disease cycle or fungicide sensitivity. To our knowledge, this is the first report of C. truncatum causing anthracnose on a member of the genus Prunus. References: (1) P. Bonants et al. EPPO Bull. 43:211, 2013. (2) I. Carbone et al. Mycologia 91:553, 1999. (3) U. Damm et al. Fungal Divers. 39:45, 2009. (4) T. J. White et al. Pages 315-322 in: PCR Protocols: A Guide to Methods and Application. Academic Press, NY, 1993.

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First Report of Brown Rot of Peach Caused by Monilinia fructicola in Southeastern China

Plant Disease ◽

10.1094/pdis-11-10-0779 ◽

2011 ◽

Vol 95 (2) ◽

pp. 225-225 ◽

Cited By ~ 5

Author(s):

M. J. Hu ◽

Y. Chen ◽

S. N. Chen ◽

X. L. Liu ◽

L. F. Yin ◽

...

Keyword(s):

Dna Sequences ◽

Prunus Persica ◽

Morphological Characteristics ◽

Brown Rot ◽

Its Sequences ◽

Monilinia Fructicola ◽

Southeastern China ◽

Fujian Province ◽

First Report ◽

Control Fruit

In 2009 and 2010, peaches (Prunus persica) with brown rot symptoms were collected from Zhejiang Plant Protection State Research Farm and a commercial orchard in Fujian Province in southeastern China. Affected fruit showed brown decay with zones of sporulation. Single-spore isolates from the diseased fruit were cultured on potato dextrose agar. After incubation at 25°C in the dark for 5 days, colonies were gray with concentric rings of sporulation. Mean mycelial growth of isolates MZ09-2a from Zhejiang Province and 0907-a from Fujian Province was 4.46 ± 0.58 and 7.05 ± 0.81 cm after 4 and 7 days of incubation, respectively. Lemon-shaped conidia were formed in branched, monilioid chains and mean size was 14.6 (9.6 to 21.6) × 10.3 (7.2 to 13.2) μm. Mean conidial germination was 97 ± 1% with one straight germ tube per conidium. These characteristics were consistent with descriptions of Monilinia fructicola (G. Wint.) Honey (3). Morphology-based species identification was confirmed by sequencing and analysis of ribosomal internal transcribed spacer (ITS) sequences. A 496-bp fragment including ITS 1 and 2 and the gene encoding the 5.8S small subunit of the ribosomal RNA from isolates MZ09-2a and 0907-a was amplified using the universal primer pair ITS1/ITS4 (4) and sequenced. Nucleotide sequences of both isolates were identical. Blast searches of the ITS sequences in GenBank showed the highest similarity (100%) with sequences of M. fructicola isolates from China (FJ515894), Italy (FJ411109), and Spain (EF207423). The isolates were also identified as M. fructicola using the Monilinia spp. PCR detection protocol based on sequence-characterized amplification region marker DNA sequences (2). Pathogenicity was confirmed by inoculating surface-sterilized, mature cv. Zhonghua 2 peaches with mycelial plugs of representative isolates. Fruit was stabbed at two points with a 5-mm-diameter sterile cork borer, mycelial plugs (5 mm in diameter) were removed from the periphery of a 4-day-old colony of each isolate and placed upside down into each wound; control fruit received water agar. Inoculated fruit developed typical brown rot symptoms with sporulating fungi while control fruit remained healthy after 3 days of incubation at 22°C in a moist chamber. Pathogens were reisolated from the inoculated fruit and confirmed to be M. fructicola on the basis of morphological characteristics. To our knowledge, this is the first report of M. fructicola in Zhejiang and Fujian provinces. Both provinces are located more than 1,000 km south of Beijing, Hebei, and Shandong provinces, where M. fructicola had been reported previously (1). References: (1) J. Y. Fan et al. Acta Phytophylacica Sin. (in Chinese) 34:289, 2007. (2) I. Gell et al. J. Appl. Microbiol. 103:2629, 2007. (3) G. C. M. van Leeuwen and H. A. van Kesteren. Can. J. Bot. 76:2041, 1998. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds., Academic Press, San Diego, 1990.

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First Report of Fusarium Rot Caused by Fusarium oxysporum on Lemon in Tucumán, Argentina

Plant Disease ◽

10.1094/pdis-01-12-0069-pdn ◽

2013 ◽

Vol 97 (7) ◽

pp. 989-989 ◽

Cited By ~ 5

Author(s):

G. M. Fogliata ◽

C. V. Martínez ◽

M. E. Acosta ◽

M. L. Muñoz ◽

L. D. Ploper

Keyword(s):

Fusarium Species ◽

Aerial Mycelium ◽

Citrus Limon ◽

Dry Rot ◽

First Report ◽

Control Fruit ◽

Inoculation Site ◽

Agar Disc ◽

Fruit Samples ◽

Fusarium Rot

Fusarium rot is considered a minor disease of citrus fruits. Several Fusarium species have been associated with fruit decay, most commonly F. lateritium Nees, F. moniliforme J. Sheld., F. oxysporum Schltdl., and F. solani (Mart.) Sacc. (2,3). In the winters of 2007, 2009, 2010, and 2011, lemon [Citrus limon (L.) Burm. f.] fruit with white mycelium covering the peduncle were submitted to the Phytopathology Lab at the Estación Experimental Agroindustrial Obispo Colombres. All fruit samples from Tucumán, Argentina, were stored in boxes kept in packinghouse for more than 1 month. In 2007 only, light to dark brown flavedo around the peduncle was observed in less than 1% of the sample fruit received. No internal breakdown was visible. No change in rind color was observed in the samples received in remaining years. Abundant Fusarium sp. conidia were observed on the mycelium. Colonies with white to violet fluffy aerial mycelium developed on potato dextrose agar (PDA) and produced abundant ovoid or oblong microconidia (1.9 to 3.6 × 4.8 to 10.8 μm), usually unicellular, borne in false heads on short monophialides, and loculated slightly falcate macroconidia were mostly three to five septate (2.4 to 4.8 × 19.2 to 31.2 μm). Unbranched and branched-monophialidic conidiophores were observed. Simple or paired chlamydospores developed on synthetic nutrient agar (1 g KH2PO4, 1 g KNO3, 0.5 g MgSO4.7H2O, 0.5 g KCl, 0.2 g sucrose, and 20 g agar/liter distilled water). On the basis of morphological and cultural criteria, 22 isolates were identified as F. oxysporum (4) designated as D1 to D22. Morfological identification was confirmed by PCR (1) using genomic DNA extracted from the mycelium of pure culture, and an amplified product of 70 bp, specific for the species F. oxysporum, was obtained. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS5 and secuenced. BLAST analysis of the 600 bp segment showed a 100% indentity with F. oxysporum, strains CCF 4362 and 1166 (GenBank Accession Nos. HE974454 and FR731133, respectively). Pathogenicity tests were conducted twice by inoculating 10 surface-disinfected wounded lemon fruit. A rind disc (5 mm in diameter and 1 mm deep) near the stem end was removed and a 5-mm-diameter agar disc of D2 isolate (grown at 25°C for 5 days on PDA) was attached to the wound replacing the rind disc. The inoculation site was covered with moistened cotton wool and the fruit were wrapped in plastic bags to prevent the inoculum from drying out. Ten control fruit were inoculated with uncultured PDA plugs (5 mm in diameter). All fruit were maintained in a growth chamber at 25°C under humid conditions. After 5 to 6 days, all inoculated fruit showed white aerial mycelium, initially on the inoculation site and then on the peduncle, similar to that observed on naturally infected fruit. After 20 days, two fruit developed stem end dry rot and showed peduncle fall but no internal breakdown was visible. Control fruit developed any symptom as described above. F. oxysporum was consistently reisolated from infected tissues, completing Koch's postulates. To our knowledge, this is the first report of Fusarium rot caused by F. oxysporum on lemon in Tucumán, Argentina. References: (1) V. Edel et al. Mycol. Res. 104:518, 2000. (2) H. S. Fawcett. Citrus Diseases and Their Control, 1936. (3) A. Z. Joffe and M. Schiffmann-Nadel. Fruits 27:117, 1972. (4) P. E. Nelson et al. Fusarium species: An Illustrated Manual for Identification, 1983.

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First report of Anthracnose on Peach Fruit Caused by Colletotrichum siamense in Uruguay

Plant Disease ◽

10.1094/pdis-05-21-0950-pdn ◽

2021 ◽

Author(s):

María Julia Carbone ◽

Victoria Moreira ◽

Pedro Mondino ◽

Sandra Alaniz

Keyword(s):

South Carolina ◽

Prunus Persica ◽

Disease Incidence ◽

Management Strategies ◽

Control Treatment ◽

Fluorescent Light ◽

Peach Fruit ◽

First Report ◽

Anthracnose Disease ◽

Equidistant Points

Peach (Prunus persica L.) is an economically important deciduous fruit crop in Uruguay. Anthracnose caused by species of the genus Colletotrichum is one of the major diseases in peach production, originating significant yield losses in United States (Hu et al. 2015), China (Du et al. 2017), Korea (Lee et al. 2018) and Brazil (Moreira et al. 2020). In February 2017, mature peach fruits cv. Pavia Canario with symptoms resembling anthracnose disease were collected from a commercial orchard located in Rincon del Colorado, Canelones, in the Southern region of Uruguay. Symptoms on peach fruit surface were characterized as circular, sunken, brown to dark-brown lesions ranging from 1 to 5 cm in diameter. Lesions were firm to touch with wrinkled concentric rings. All lesions progressed to the fruit core in a V-shaped pattern. The centers of the lesions were covered by orange conidial masses. Monosporic isolates obtained from the advancing margin of anthracnose lesions were grown on PDA at 25ºC and 12h photoperiod under fluorescent light. The representative isolates DzC1, DzC2 and DzC6 were morphologically and molecularly characterized. Upper surface of colonies varied from white or pale-gray to gray and on the reverse dark-gray with white to pale-gray margins. Conidia were cylindrical, with both ends predominantly rounded or one slightly acute, hyaline and aseptate. The length and width of conidia ranged from 9.5 to 18.9 µm (x ̅=14.1) and from 3.8 to 5.8 µm (x ̅=4.6), respectively. The ACT, βTUB2, GAPDH, APN2, APN2/MAT-IGS, and GAP2-IGS gene regions were amplified and sequenced with primers ACT-512F/ACT-783R (Carbone and Kohn, 1999), BT2Fd/BT4R (Woudenberg et al. 2009), GDF1/GDR1 (Guerber et al. 2003), CgDLR1/ColDLF3, CgDLF6/CgMAT1F2 (Rojas et al. 2010) and GAP1041/GAP-IGS2044 (Vieira et al. 2017) respectively and deposited in the GenBank database (MZ097888 to MZ097905). Multilocus phylogenetic analysis revealed that Uruguayan isolates clustered in a separate and well supported clade with sequences of the ex-type (isolate ICMP 18578) and other C. siamense strains (isolates Coll6, 1092, LF139 and CMM 4248). To confirm pathogenicity, mature and apparently healthy peach fruit cv. Pavia Canario were inoculated with the three representative isolates of C. siamense (six fruit per isolate). Fruit were surface disinfested with 70% ethanol and wounded with a sterile needle at two equidistant points (1 mm diameter x 1 mm deep). Then, fruit were inoculated with 5 µl of a spore suspension (1×106 conidia mL-1) in four inoculation points per fruit (two wounded and two unwounded). Six fruit mock-inoculated with 5 µl sterile water were used as controls. Inoculated fruit were placed in moist chamber and incubated at 25°C during 10 days. Anthracnose lesions appeared at 2 and 4 days after inoculation in wounded and unwounded points, respectively. After 7 days, disease incidence was 100% and 67% for wounded and unwounded fruit, respectively. The control treatment remained symptomless. The pathogens were re-isolated from all lesions and re-identified as C. siamense. C. siamense was previously reported in South Carolina causing anthracnose on peach (Hu et al. 2015). To our knowledge, this is the first report of anthracnose disease on peach caused by C. siamense in Uruguay. Effective management strategies should be implemented to control anthracnose and prevent the spread of this disease to other commercial peach orchards.

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First report of Coleus blumei viroid 1 in commercial Coleus blumei in the United States

Plant Disease ◽

10.1094/pdis-05-21-0917-pdn ◽

2021 ◽

Author(s):

Gardenia Orellana ◽

Alexander V Karasev

Keyword(s):

United States ◽

Leaf Tissue ◽

The United States ◽

Universal Primers ◽

Rt Pcr ◽

Universal Primer ◽

Tissue Samples ◽

First Report ◽

Specific Pcr ◽

Coleus Blumei

Coleus scutellarioides (syn. Coleus blumei) is a widely grown evergreen ornamental plant valued for its highly decorative variegated leaves. Six viroids, named Coleus blumei viroid 1 to 6 (CbVd-1 to -6) have been identified in coleus plants in many countries of the world (Nie and Singh 2017), including Canada (Smith et al. 2018). However there have been no reports of Coleus blumei viroids occurring in the U.S.A. (Nie and Singh 2017). In April 2021, leaf tissue samples from 27 cultivars of C. blumei, one plant of each, were submitted to the University of Idaho laboratory from a commercial nursery located in Oregon to screen for the presence of viroids. The sampled plants were selected randomly and no symptoms were apparent in any of the samples. Total nucleic acids were extracted from each sample (Dellaporta et al. 1983) and used in reverse-transcription (RT)-PCR tests (Jiang et al. 2011) for the CbVd-1 and CbVd-5 with the universal primer pair CbVds-P1/P2, which amplifies the complete genome of all members in the genus Coleviroid (Jiang et al. 2011), and two additional primer pairs, CbVd1-F1/R1 and CbVd5-F1/R1, specific for CbVd-1 and CbVd-5, respectively (Smith et al. 2018). Five C. blumei plants (cvs Fire Mountain, Lovebird, Smokey Rose, Marrakesh, and Nutmeg) were positive for a coleviroid based on the observation of the single 250-nt band in the RT-PCR test with CbVds-P1/P2 primers. Two of these CbVd-1 positive plants (cvs Lovebird and Nutmeg) were also positive for CbVd-1 based on the presence of a single 150-nt band in the RT-PCR assay with CbVd1-F1/R1 primers. One plant (cv Jigsaw) was positive for CbVd-1, i.e. showing the 150-nt band in RT-PCR with CbVd1-F1/R1 primers, but did not show the ca. 250-bp band in RT-PCR with primers CbVds-P1/P2. None of the tested plants were positive for CbVd-5, either with the specific, or universal primers. All coleviroid- and CbVd-1-specific PCR products were sequenced directly using the Sanger methodology, and revealed whole genomes for five isolates of CbVd-1 from Oregon, U.S.A. The genomes of the five CbVd-1 isolates displayed 96.9-100% identity among each other and 96.0-100% identity to the CbVd-1 sequences available in GenBank. Because the sequences from cvs Lovebird, Marrakesh, and Nutmeg, were found 100% identical, one sequence was deposited in GenBank (MZ326145). Two other sequences, from cvs Fire Mountain and Smokey Rose, were deposited in the GenBank under accession numbers MZ326144 and MZ326146, respectively. To the best of our knowledge, this is the first report of CbVd-1 in the United States.

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First Report of Plum pox virus (Sharka Disease) in Prunus persica in the United States

Plant Disease ◽

10.1094/pdis.2000.84.2.202b ◽

2000 ◽

Vol 84 (2) ◽

pp. 202-202 ◽

Cited By ~ 65

Author(s):

L. Levy ◽

V. Damsteegt ◽

R. Welliver

Keyword(s):

Prunus Persica ◽

Virus Disease ◽

Sandwich Elisa ◽

Pcr Amplification ◽

The United States ◽

Enzyme Linked Immunosorbent Assay ◽

Plum Pox Virus ◽

Rt Pcr ◽

Peach Fruit ◽

First Report

Plum pox (Sharka) is the most important virus disease of Prunus in Europe and the Mediterranean region and is caused by Plum pox potyvirus (PPV). In September 1999, PPV-like symptoms were observed in peach fruit culls in a packinghouse in Pennsylvania. All symptomatic fruit originated from a single block of peach (P. persica cv. Encore) in Adams County. Trees in the block exhibited ring pattern symptoms on their leaves. A potyvirus was detected in symptomatic fruit using the Poty-Group enzyme-linked immunosorbent assay (ELISA) test from Agdia (Elkhart, IN). Reactions for symptomatic peach fruit and leaves also were positive using triple-antibody sandwich ELISA with the PPV polyclonal antibody from Bioreba (Carrboro, NC) for coating, the Poty-Group monoclonal antibody (MAb; Agdia) as the intermediate antibody, and double-antibody sandwich ELISA with PPV detection kits from Sanofi (Sanofi Diagnostics Pasteur, Marnes-La-Coquette, France) and Agdia and the REAL PPV kit (Durviz, Valencia, Spain) containing universal (5B) and strain typing (4DG5 and AL) PPV MAbs (1). PPV also was identified by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) amplification and subsequent sequencing of the 220-bp 3′ noncoding region (2) (>99% sequence homology to PPV) and by IC-RT-PCR amplification of a 243-bp product in the coat protein (CP) gene (1). The virus was identified as PPV strain D based on serological typing with strainspecific MAbs and on PCR-restriction fragment length polymorphism of the CP IC-RT-PCR product with Rsa1 and Alu1 (1). This is the first report of PPV in North America. References: (1) T. Candresse et al. Phytopathology 88:198, 1998. (2) L. Levy and A. Hadidi. EPPO Bull. 24:595, 1994.

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First Report of Brown Rot Caused by Monilinia fructicola Affecting Peach Orchards in Slovenia

Plant Disease ◽

10.1094/pdis-94-9-1166a ◽

2010 ◽

Vol 94 (9) ◽

pp. 1166-1166 ◽

Cited By ~ 15

Author(s):

A. Munda ◽

M. Viršček Marn

Keyword(s):

Prunus Persica ◽

Brown Rot ◽

Fruit Rot ◽

Morphological Identification ◽

Monilinia Fructicola ◽

Conidial Suspension ◽

Stone Fruits ◽

The European Union ◽

First Report ◽

Representative Isolate

Monilinia fructicola, the causal agent of brown rot, is a destructive fungal pathogen that affects mainly stone fruits (Prunoideae). It causes fruit rot, blossom wilt, twig blight, and canker formation and is common in North and South America, Australia, and New Zealand. M. fructicola is listed as a quarantine pathogen in the European Union and was absent from this region until 2001 when it was detected in France. In August 2009, mature peaches (Prunus persica cv. Royal Glory) with brown rot were found in a 5-year-old orchard in Goriška, western Slovenia. Symptoms included fruit lesions and mummified fruits. Lesions were brown, round, rapidly extending, and covered with abundant gray-to-buff conidial tufts. The pathogen was isolated in pure culture and identified based on morphological and molecular characters. Colonies on potato dextrose agar (PDA) incubated at 25°C in darkness had an average daily growth rate of 7.7 mm. They were initially colorless and later they were light gray with black stromatal plates and dense, hazel sporogenous mycelium. Colony margins were even. Sporulation was abundant and usually developed in distinct concentric zones. Limoniform conidia, produced in branched chains, measured 10.1 to 17.7 μm (mean = 12.1 μm) × 6.2 to 8.6 μm (mean = 7.3 μm) on PDA. Germinating conidia produced single germ tubes whose mean length ranged from 251 to 415 μm. Microconidia were abundant, globose, and 3 μm in diameter. Morphological characters resembled those described for M. fructicola (1). Morphological identification was confirmed by amplifying genomic DNA of isolates with M. fructicola species-specific primers (2–4). Sequence of the internal transcribed spacer (ITS) region (spanning ITS1 and ITS 2 plus 5.8 rDNA) of a representative isolate was generated using primers ITS1 and ITS4 and deposited in GenBank (Accession No. GU967379). BLAST analysis of the 516-bp PCR product revealed 100% identity with several sequences deposited for M. fructicola in NCBI GenBank. Pathogenicity was tested by inoculating five mature surface-sterilized peaches with 10 μl of a conidial suspension (104 conidia ml–1) obtained from one representative isolate. Sterile distilled water was used as a control. Peaches were wounded prior to inoculation. After 5 days of incubation at room temperature and 100% relative humidity, typical brown rot symptoms developed around the inoculation point, while controls showed no symptoms. M. fructicola was reisolated from lesion margins. Peach and nectarine orchards in a 5-km radius from the outbreak site were surveyed in September 2009 and M. fructicola was confirmed on mummified fruits from seven orchards. The pathogen was not detected in orchards from other regions of the country, where only the two endemic species M. laxa and M. fructigena were present. To our knowledge, this is the first report of M. fructicola associated with brown rot of stone fruits in Slovenia. References: (1) L. R. Batra. Page 106 in: World Species of Monilinia (Fungi): Their Ecology, Biosystematics and Control. J. Cramer, Berlin, 1991. (2) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (3) K. J. D. Hughes et al. EPPO Bull. 30:507, 2000. (4) R. Ioos and P. Frey. Eur. J. Plant Pathol. 106:373, 2000.

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