First Report of Botrytis cinerea Causing Gray Mold of Pomegranate (Punica granatum) in Greece

Pomegranate is rapidly increasing in production in Greece. During August of 2008 in the region of Larisa (central Greece), preharvest fruit rot was observed on pomegranate (cv. Kapmaditika) that caused losses estimated at 10%. Symptoms first appeared as small spots on the fruits that later increased in size and developed into expanded, dark brown lesions. Internally, tissues were soft and brown with gray mycelia and conidiophores observed. Affected fruits decayed completely during 2 months of storage (5 to 6°C), causing yield losses of up to 20%. To isolate the casual agent, conidia and conidiophores were scraped aseptically from the internal tissues, suspended in sterile water, and streaked onto the surface of potato dextrose agar (PDA). Single hyphal tips were transferred to PDA, and the isolated fungus was identified as Botrytis cinerea Pers.:Fr. on the basis of morphological characteristics (2). B. cinerea was consistently isolated from symptomatic tissues. Colonies of B. cinerea on PDA were at first colorless and became gray to brown with the development of lemon-shaped conidia (average 7.5 × 9 μm). Sclerotia were black and varied in size (1.4 to 4.5 × 1.5 to 2.7 mm) and shape (2). Pathogenicity of the isolated fungus was tested by wound inoculating five mature pomegranate fruits (cv. Kampaditika) after surface sterilization with 5% sodium hypochlorite. Plugs of the fungus (5 mm in diameter) obtained from the colony margins were transferred onto a 3- × 3-mm wound on the surface of sterilized fruit. Sterile PDA plugs were used to inoculate five control pomegranate fruits. Fruit were incubated at 22°C and 80% relative humidity in the dark. Extensive decay, similar to that observed on diseased fruits in the field, was observed on inoculated fruits 7 days after inoculation, whereas control fruits showed no decay. The pathogen was reisolated from internal rotten tissues of inoculated fruit, but not from the noninoculated control fruits. Fruit rot of pomegranate caused by B. cinerea has been reported previously in the United States (1) and China (3). However, to our knowledge, this is the first report of B. cinerea causing gray mold of pomegranate in Greece. References: (1) A. M. French. California Plant Disease Host Index. Calif. Dept. Food Agric., Sacramento, 1989. (2) W. B. Hewitt. Compendium of Grape Diseases. American Phytopathological Society, 1994. (3) Z. Zhang. Flora Fungorum Sinicorum 26:277, 2006.

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First Report of Botrytis Leaf Blight and Fruit Rot on Schisandra chinensis Caused by Botrytis cinerea in China

Plant Disease ◽

10.1094/pdis-02-11-0086 ◽

2011 ◽

Vol 95 (6) ◽

pp. 769-769

Author(s):

R. H. Yu ◽

J. Gao ◽

J. Wang ◽

X. Wang

Keyword(s):

Botrytis Cinerea ◽

Morphological Characteristics ◽

Gray Mold ◽

Leaf Blight ◽

Jilin Province ◽

Fruit Rot ◽

Conidial Suspension ◽

Schisandra Chinensis ◽

Mycelium Growth ◽

First Report

Schisandra (Schisandra chinensis (Turcz.) Baill) is a perennial plant belonging to Magnoliaceae. It is a very important medicinal herb in China and is mainly used for treatment of insomnia and memory decay. From July to September 2008, an unknown leaf blight and fruit rot on schisandra were first observed at Jingyu County, Jilin Province. The same symptoms were detected in other areas of Jilin Province, such as Ji'an City, Baishan City, and Hunchun City. Initially, some small, brown spots appeared on the tip or margin of the leaves. Light brown or brown necrotic lesions developed and eventually covered entire leaves. Seriously affected leaves were rolled or distorted and eventually became completely dry and brittle. Small spots appeared on the surface of mature fruits, coalesced, and the fruits finally dropped. Gray mycelia and conidiophores developed on the diseased leaves and fruits. To isolate the causal agent, conidia and conidiophores were scraped aseptically from the internal tissues, suspended in sterile water, and streaked onto the surface of potato dextrose agar (PDA). Single-hyphal tips were transferred on PDA and the isolated fungus was identified as Botrytis cinerea Pers.: Fr. on the basis of its morphological characteristics and internal transcribed spacer (ITS) sequence. Colonies of B. cinerea on PDA were colorless at first and became gray to brown 20 days later with the mycelium growth and conidia producing in cultures. Conidia are single celled, lemon shaped, colorless to a light color, and 4.4 to 15.0 × 7.0 to 10.0 μm. Sclerotia formed about 1 week later, were black-brown and varied in size (2.0 to 5.0 × 2.0 to 4.0 mm) and shape. The ITS region of rDNA was amplified from DNA extracted from single-spore isolate BC12 of B. cinerea using primers ITS4/ITS5 and sequenced (GenBank Accession No. GU724512), BLAST analysis (1) of the 535-bp segment showed 99% similarity with the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). Pathogenicity tests were carried out on healthy schisandra plants that were 4 years old. After the surface of the leaves and fruits was disinfected with 5% sodium hypochlorite, a conidial suspension of 105 conidia/ml was sprayed on 10 schisandra leaves, and plugs of the fungus obtained from the colony margins were transferred onto a 3- × 3-mm wound on the surface of disinfected fruit. Ten control schisandra leaves and 10 fruits were inoculated at the same time. Plants were covered with polyethylene bags and incubated at 25°C in a greenhouse with relative humidity of 85% for 3 days. Similar symptoms to those observed on diseased leaves and fruits in the field were observed on inoculated schisandra leaves and fruits 7 days after inoculation, whereas control leaves and fruits showed no symptoms. The pathogen was successfully reisolated. The gray mold disease caused by B. cinerea was reported in many plants, such as Lavandula stoechas and Chamelaucium uncinatum in Italy (2,3). However, to our knowledge, this is the first report of gray mold disease of schisandra caused by B. cinerea in China. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) A. Garibaldi et al. Plant Dis. 94:968, 2009. (3) A. Garibaldi et al. Plant Dis. 94:380, 2010.

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First Report of Leaf Spot Caused by Botrytis cinerea on Cardamine hupingshanensis in China

Plant Disease ◽

10.1094/pdis-04-21-0698-pdn ◽

2021 ◽

Author(s):

Jun Guo ◽

Jin Chen ◽

Zhao Hu ◽

Jie Zhong ◽

Jun Zi Zhu

Keyword(s):

Botrytis Cinerea ◽

Morphological Characteristics ◽

Gray Mold ◽

Hunan Province ◽

Conidial Suspension ◽

Heat Shock Protein 60 ◽

Basal Cells ◽

Single Spore ◽

Internal Transcribed Spacer Region ◽

First Report

Cardamine hupingshanensis is a selenium (Se) and cadmium (Cd) hyperaccumulator plant distributed in wetlands along the Wuling Mountains of China (Zhou et al. 2018). In March of 2020, a disease with symptoms similar to gray mold was observed on leaves of C. hupingshanensis in a nursery located in Changsha, Hunan Province, China. Almost 40% of the C. hupingshanensis (200 plants) were infected. Initially, small spots were scattered across the leaf surface or margin. As disease progressed, small spots enlarged to dark brown lesions, with green-gray, conidia containing mold layer under humid conditions. Small leaf pieces were cut from the lesion margins and were sterilized with 70% ethanol for 10 s, 2% NaOCl for 2 min, rinsed with sterilized distilled water for three times, and then placed on potato dextrose agar (PDA) medium at 22°C in the dark. Seven similar colonies were consistently isolated from seven samples and further purified by single-spore isolation. Strains cultured on PDA were initially white, forming gray-white aerial mycelia, then turned gray and produced sclerotia after incubation for 2 weeks, which were brown to blackish, irregular, 0.8 to 3.0 × 1.2 to 3.5 mm (n=50). Conidia were unicellular, globose or oval, colourless, 7.5 to 12.0 × 5.5 to 8.3 μm (n=50). Conidiophores arose singly or in group, straight or flexuous, septate, brownish to light brown, with enlarged basal cells, 12.5 to 22.1 × 120.7 to 310.3 μm. Based on their morphological characteristics in culture, the isolates were putatively identified as Botrytis cinerea (Ellis 1971). Genomic DNA of four representative isolates, HNSMJ-1 to HNSMJ-4, were extracted by CTAB method. The internal transcribed spacer region (ITS), glyceraldehyde-3-phosphate dehydrogenase gene (G3PDH), heat-shock protein 60 gene (HSP60), ATP-dependent RNA helicaseDBP7 gene (MS547) and DNA-dependent RNA polymerase subunit II gene (RPB2) were amplified and sequenced using the primers described previously (Aktaruzzaman et al. 2018) (MW820311, MW831620, MW831628, MW831623 and MW831629 for HNSMJ-1; MW314722, MW316616, MW316617, MW316618 and MW316619 for HNSMJ-2; MW820519, MW831621, MW831627, MW831624 and MW831631 for HNSMJ-3; MW820601, MW831622, MW831626, MW831625 and MW831630 for HNSMJ-4). BLAST searches showed 99.43 to 99.90% identity to the corresponding sequences of B. cinerea strains, such as HJ-5 (MF426032.1, MN448500.1, MK791187.1, MH727700.1 and KX867998.1). A combined phylogenetic tree using the ITS, G3PDH, HSP60 and RPB2 sequences was constructed by neighbor-joining method in MEGA 6. It revealed that HNSMJ-1 to HNSMJ-4 clustered in the B. cinerea clade. Pathogenicity tests were performed on healthy pot-grown C. hupingshanensis plants. Leaves were surface-sterilized and sprayed with conidial suspension (106 conidia/ mL), with sterile water served as controls. All plants were kept in growth chamber with 85% humidity at 25℃ following a 16 h day-8 h night cycle. The experiment was repeated twice, with each three replications. After 4 to 7 days, symptoms similar to those observed in the field developed on the inoculated leaves, whereas controls remained healthy. The pathogen was reisolated from symptomatic tissues and identified using molecular methods, confirming Koch’s postulates. B. cinerea has already been reported from China on C. lyrate (Zhang 2006), a different species of C. hupingshanensis. To the best of our knowledge, this is the first report of B. cinerea causing gray mold on C. hupingshanensis in China and worldwide. Based on the widespread damage in the nursery, appropriate control strategies should be adopted. This study provides a basis for studying the epidemic and management of the disease.

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First Report of Botrytis Blight of Peanut Caused by Botrytis cinerea in Georgia

Plant Disease ◽

10.1094/pd-89-0910c ◽

2005 ◽

Vol 89 (8) ◽

pp. 910-910 ◽

Cited By ~ 2

Author(s):

J. E. Woodward ◽

T. B. Brenneman ◽

R. C. Kemerait ◽

A. K. Culbreath ◽

J. R. Clark

Keyword(s):

Botrytis Cinerea ◽

Disease Incidence ◽

Block Design ◽

Gray Mold ◽

American Phytopathological Society ◽

Breeding Programs ◽

First Report ◽

Tomato Spotted Wilt ◽

Arachis Hypogaea L ◽

Wilt Virus

Because of the importance of spotted wilt caused by Tomato spotted wilt virus (TSWV), most peanut (Arachis hypogaea L.) breeding programs in the southeastern United States are focusing on developing resistance to TSWV. Many of the cultivars with improved resistance to TSWV are late maturing, requiring 150 days to reach optimum maturity. This factor could greatly impact disease problems at harvest. During November of 2004, an unknown disease was observed on peanut cvs. Georgia 02-C and Hull in a commercial field in Appling County. Symptoms included wilting stems with water-soaked lesions and a dense, gray mold growing on infected tissues. Final disease incidence was less than 5%. For isolation, diseased tissue was surface sterilized by soaking in 0.5% sodium hypochlorite for 1 min, air dried, plated on potato dextrose agar (PDA), and incubated at 20°C. Botrytis cinerea Pers.:Fr., causal agent of Botrytis blight, was isolated from the margins of infected tissue. Mycelia were initially white but became gray after 72 h at which time tall, branched, septate conidiophores formed. Mature, unicellular, ellipsoid, hyaline conidia (8.9 × 10.4 μm) formed in botryose heads (1). Hard, black, irregular-shaped sclerotia formed after 2 weeks. Stems of greenhouse-grown peanut plants (cv. Georgia Green) were inoculated with PDA plugs colonized with either B. cinerea or B. allii Munn. Inoculations were made 3 cm below the last fully expanded leaf on wounded and nonwounded tissue. Noncolonized PDA plugs served as controls (n = 9). Plants were arranged in a dew chamber at 20°C in a randomized complete block design. Lesions and spore masses identical to those observed in the field appeared 3 to 5 days after being inoculated with B. cinerea. The B. allii inoculations caused only superficial lesions. After 5 days, mean lesion lengths for B. cinerea were 59 and 37 mm for wounded and nonwounded inoculations, respectively. B. cinerea was recovered from 100% of the symptomatic tissues. Botrytis blight is considered a late-season disease that occurs in cool, wet weather (3). Symptoms similar to those of Botrytis blight were observed on mature and over-mature peanut in Georgia and have been cited as “unpublished observations” (2); however, to our knowledge, this is the first report of the disease in Georgia. Although Botrytis blight is not considered a major peanut disease, it may become more prevalent at harvest as producers utilize late-maturing cultivars to manage spotted wilt. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Guide of Imperfect Fungi. 4th ed. The American Phytopathological Society, St. Paul, MN, 1998. (2) K. H. Garren and C. Wilson. Peanut Diseases. Pages 262–333 in: The Peanut, the Unpredictable Legume. The National Fertilizer Assoc. Washington D.C. 1951. (3) D. M. Porter. Botrytis blight. Pages 10–11 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathological Society, St. Paul, MN. 1997.

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First Report of Gray Mold Caused by Botrytis cinerea on Greenhouse-Grown Zucchini in Korea

Plant Disease ◽

10.1094/pdis-01-13-0005-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1116-1116 ◽

Cited By ~ 1

Author(s):

W. Cheon ◽

Y. H. Jeon

Keyword(s):

New York ◽

Botrytis Cinerea ◽

Severe Disease ◽

Morphological Characteristics ◽

Its Region ◽

Gray Mold ◽

Greenhouse Production ◽

First Report ◽

Plastic Bags ◽

Diseased Fruit

In the winter of 2011, greenhouse-grown zucchini (Cucurbita pepo) in Andong City, Korea, showed severe disease symptoms on fruits and dying leaves of zucchini plants that resembled gray mold disease with about 20% yield loss. Symptoms included extensive growth of mycelia and gray conidia on stem and fruit lesions. Lesions expanded rapidly under cool, humid conditions. As the disease progressed, leaves, stems, and fruits became necrotic and were covered by an abundant, soft, gray, sporulating mycelium. Diseased fruit tissue was excised and surface sterilized by immersion in 2% NaOCl for 1 min, placed on PDA (potato dextrose agar), and incubated at 22°C. Fungal colonies were initially white and became gray to brown after 72 h. Analysis of light micrographs showed the presence of elliptical conidia on PDA that was 7.5 to 16.0 μm long and 5 to 10.5 μm wide. In culture, a few, black, small and large irregular sclerotia were produced. Microsclerotia were round, spherical or irregular in shape, and ranged from 1.0 to 3.3 and 1.2 to 3.4 mm (width and length). Conidiophores were slender and branched with enlarged apical cells bearing smooth, ash-colored conidia. These morphological characteristics identified the fungus as Botrytis cinerea (1). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 (forward) and ITS4 (reverse) primer set (ITS1: 5′-TCCGTAGGTGAACCTGCGG-3′, ITS4: 5′-TCCTCCGCTTATTGATATGC-3′) and sequenced (2). BLAST analysis of the PCR product showed that the sequence had 100% identity with the nucleotide sequences for B. cinerea. Pathogenicity tests were performed by placing mycelium fragments (1 cm2) of PDA cultures on zucchini fruits. Controls were treated with PDA alone. Five replicates for the inoculated and control plants were used. All fruits were covered with plastic bags and incubated in a growth chamber to maintain 90 to 100% relative humidity at 22°C. Typical symptoms appeared 2 to 6 days after inoculation. The inoculated plants developed typical gray mold symptoms with gray sporulating lesions, while controls remained healthy with no lesions. B. cinerea reisolated from the inoculated tissues was morphologically identical to the original isolates. In a cold outside (below 0°C), wet greenhouse, plants are likely to be exposed to resident Botrytis populations and if the gray mold disease occurs, it can spread on zucchini plants very fast, in 2 days to a week inside a 100 m2 greenhouse. Therefore, gray mold disease could have a significant impact on greenhouse production of zucchini. To our knowledge, this is the first report of B. cinerea causing gray mold of greenhouse-grown zucchini in Korea. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (2) T. J. White et al. PCR Protocols. Academic Press, Inc., New York, 1990.

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First Report of Fruit Rot and Associated Branch Dieback of Almond in California Caused by a Phomopsis Species Tentatively Identified as P. amygdali

Plant Disease ◽

10.1094/pdis.1999.83.11.1073c ◽

1999 ◽

Vol 83 (11) ◽

pp. 1073-1073 ◽

Cited By ~ 7

Author(s):

J. E. Adaskaveg ◽

H. Förster ◽

J. H. Connell

Keyword(s):

Disease Incidence ◽

Morphological Characteristics ◽

The United States ◽

Tree Canopy ◽

Fruit Rot ◽

Control Treatment ◽

Field Inoculation ◽

First Report ◽

Branch Dieback ◽

Summer Fruit

A fruit rot of almond (Prunus dulcis (Mill.) D. Webb.) was observed in an orchard in Durham, CA (Butte County), in June of 1998 after an unusually wet spring with a total precipitation of 17.2 cm for April and May. Disease incidence on fully developed fruit of almond cv. Sonora was nearly 90% in the lower tree canopy by July. Almond cv. Nonpareil grown in alternate rows in the same orchard was much less affected. Fruit symptoms included extensive grayish brown discolored and shriveled hulls, often associated with a clear gum secretion and shriveled kernels. Affected fruit frequently abscised. Leaf symptoms and branch dieback were not associated with the disease in 1998. In May of 1999, however, extensive twig dieback was observed on almond cv. Sonora in the same orchard. Isolations from more than 100 symptomatic fruit were conducted from 9 sampling sites in the 9-ha orchard. Based on morphological characteristics, the same fungus was isolated from 93% of the fruit. The fungus also was isolated consistently from samples exhibiting twig dieback. During a major disease survey conducted in 1998, the fungus was only incidentally isolated from almond fruit from other California orchards. Ascomata were not observed in vivo or in vitro. The fungus produced alpha and beta spores in pycnidia when cultured on potato dextrose agar. Spore measurements were obtained from 10 spores for each of 3 isolates obtained from fruit or twig dieback of almond cv. Sonora. Conidial dimensions of fruit and twig isolates were very similar. Based on spore sizes, with alpha spores measuring 5.3 to 7.5 (to 8) × 1.7 to 2.5 μm and beta spores measuring12.8 to 29.8 × 0.6 to 0.7 μm, the fungus was tentatively identified as Phomopsis amygdali (Del.) Tuset & Portilla (2). Previous reports on this fungus (2), however, indicated that beta spores are not produced in culture, and disease symptoms have not been observed on fruit. The fungus was morphologically different from other species of Phomopsis reported from almond and other Prunus species, including P. mali Roberts, P. padina (Sacc. & Roum.) Died., P. parabolica Petrak, P. perniciosa Grove, P. pruni (Ellis & Dearn.) Wehm., P. prunorum (Cooke) Grove, P. ribetejana Camara, and P. stipata (Lib.) Sutton (3). Field inoculation studies were performed in May of 1999 on almond cvs. Carmel and Mission. Almond fruit were wounded (2 × 2 × 2 mm) or left unwounded and were sprayed with water (control) or a suspension of alpha spores (105 spores per ml). Branches were bagged for 4 days to maintain high humidity. Fruit symptoms on cv. Carmel were observed after 4 weeks on wounded and nonwounded inoculated fruit, and P. amygdali was successfully reisolated from diseased tissue. No symptoms were observed in the control treatment for almond cv. Carmel or in any treatment for cv. Mission. This is the first report of P. amygdali causing a late spring and summer fruit rot and associated branch dieback of almond in North America (1). References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. (2) J. J. Tuset and M. T. Portilla. Taxonomic status of Fusicoccum amygdali and Phomopsis amygdalina. Can. J. Bot. 67:1275, 1989. (3) F. A. Uecker. 1988. A World List of Phomopsis Names with Notes on Nomenclature, Morphology, and Biology. Mycologia Memoir No. 13. J. Cramer, Berlin.

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First Report of Phomopsis Fruit Decay on Apple Caused by Phomopsis mali in Greece

Plant Disease ◽

10.1094/pd-90-0375c ◽

2006 ◽

Vol 90 (3) ◽

pp. 375-375 ◽

Cited By ~ 1

Author(s):

G. S. Karaoglanidis ◽

G. Bardas

Keyword(s):

Morphological Characteristics ◽

The United States ◽

Northern Greece ◽

First Report ◽

Surface Sterilization ◽

Fruit Decay ◽

Significant Yield ◽

Almost All ◽

Mature Apple ◽

Apple Fruits

From 2002 to 2005, a previously unreported disease causing significant yield losses was observed on apple fruits (cv. Red Chief) in the region of Imathia in northern Greece. Almost all apple orchards in that area, cultivated with Red Chief, showed disease symptoms on 3 to 10% of the fruits. Diseased fruits showed irregularly shaped, water-soaked areas on the skin and extensive decay internally. In most of the fruits, decay appeared to initiate internally from the calyx tube. Infected fruits remained firm during the early stages of decay. Fungal isolates obtained from small pieces of decayed tissue on potato dextrose agar (PDA) medium were identified as Phomopsis mali Roberts on the basis of morphological characteristics (2). Cultures grew rapidly on PDA at 22°C in the dark. They were initially white, but approximately 30 days after inoculation they turned gray because of the formation of pycnidia that contained α- and β-spores. α -Spores were short and elliptical in shape (8 to 10 × 2 to 3 μm) while β-spores were long (22 to 25 × 1 to 2 μm). Pathogenicity of the isolated cultures was tested by wound inoculating five mature apple fruits (cv. Red Chief) after surface sterilization with 0.5% NaOCl. PDA plugs, 5 mm in diameter with actively growing mycelium, were transferred into the flesh of the fruits. Sterile PDA plugs were used to inoculate five control apple fruits. Inoculated fruits were kept at 23°C for 10 days in the growth chamber. Extensive decay, similar to that observed on diseased fruits in the field, was observed on the inoculated fruits, whereas control fruits showed no decay. P. mali was reisolated from the decayed tissues. Commercial losses due to fruit decay caused by the pathogen have previously been reported in the United States and Northern Ireland (1). To our knowledge, this is the first report of Phomopsis fruit decay on apples in Greece. References: (1) A. C. Jones and H. S. Aldwinckle eds. Compendium of Apple and Pear Diseases. The American Phytopathological Society. St. Paul, MN, 1990. (2) D. A. Rosenberger and T. J. Burr.

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First Report of Gliocephalotrichum bacillisporum Causing Fruit Rot of Rambutan (Nephelium lappaceum) in Malaysia

Plant Disease ◽

10.1094/pdis-09-12-0831-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1110-1110

Author(s):

M. A. Intan Sakinah ◽

Z. Latiffah

Keyword(s):

Morphological Characteristics ◽

Culture Collection ◽

Fruit Rot ◽

Tropical Fruit ◽

First Report ◽

Surface Sterilization ◽

Nephelium Lappaceum ◽

Its Regions ◽

Mycelial Plug ◽

Β Tubulin

Rambutan (Nephelium lappaceum L.) is among the tropical fruit grown in Malaysia and the demand for export rose in 2011. A fruit rot was observed between August and December 2011 from several areas in the states of Pulau Pinang and Perak, Malaysia. The symptoms initially appeared as light brown, water-soaked lesions that developed first in the pericarp and pulp, later enlarging and becoming dark brown. Greyish brown mycelia were observed on infected areas that turned yellowish at later stages of infection. Gliocephalotrichum bacillisporum was isolated from infected fruit by surface sterilization techniques. Conidia were mass-transferred onto potato dexstrose agar (PDA) plates and incubated at 27 ± 1°C. Tissue pieces (5 × 5 mm) excised from the margins between infected and healthy areas were then surface sterilized in 1% sodium hypochlorite for 3 to 5 min before being rinsed with distilled water, plated on PDA, and incubated at 27 ± 1°C for 7 days. Ten isolates of G. bacillisporum were obtained. Colonies on PDA were initially white before turning yellow with a feathery appearance. Microscopic characteristics on carnation leaf agar (CLA) consisted of hyaline conidia that were slightly ellipsoid to bacilliform with rounded apex ranging from 6.0 to 8.5 μm long and 2.0 to 2.5 μm wide. Conidiophores (70 to 130 μm long) were mostly single arising from large hypha approximately 13 to 16 μm. The conidiogenous structures were mostly quadriverticillate with dense, short, penicillate branches. The phialides were cylindrical and finger-like. Chlamydospores were present singly, in groups of 2 to 4, or in occasionally branched short chains and were brown in color with thick walls ranging from 11 to 13 μm. The cultural and morphological characteristics of G. bacillisporum isolates in the present study were very similar to previously published descriptions (1) except the conidiophores formed without sterile stipe extensions. All the G. bacillisporum isolates were deposited in culture collection at the Plant Pathology Lab, University Sains Malaysia, Penang. Molecular identification was accomplished from the ITS regions using ITS1 and ITS2 primers, and the β-tubulin gene using Bt2a and Bt2b primers (2). BLAST results from the ITS regions showed a 98 to 99% similarity with sequences of G. bacillisporum isolates reported in GenBank. Accession numbers of G. bacillisporum ITS regions: JX484850, JX484852, JX484853, JX484856, JX484858, JX484860, JX484862, JX484866, JX484867, and JX484868. The identity of G. bacillisporum isolates infecting rambutan was further confirmed by β-tubulin sequences (KC683909, KC683911, KC683912, KC683916, KC683919, KC683920, KC683923, KC683926, and KC683927), which showed 92 to 95% similarity with sequences of G. bacillisporum. Pathogenicity tests were also performed using mycelial plug (5 mm) and sprayed conidial suspensions (20 μl suspension of 106 conidia/ml) prepared from 7-day-old cultures. Inoculated fruits were incubated at 27 ± 1°C and after 10 days, similar rotting symptoms appeared on the fruit surface. The pathogen was reisolated from fruit rot lesions, thus fulfilling Koch's postulates, and tests were repeated twice. To our knowledge, this is the first report of G. bacillisporum causing fruit rot of rambutan (N. lappaceum L.) in Malaysia. References: (1) C. Decock et al. Mycologia 98:488, 2006. (2) N. L. Glass and G. C. Donaldson. Appl. Environ Microbiol. 61:1323, 1995.

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First Report of Fusarium solani Fruit Rot of Pumpkin (Cucurbita pepo) in Trinidad

Plant Disease ◽

10.1094/pdis-93-5-0547b ◽

2009 ◽

Vol 93 (5) ◽

pp. 547-547

Author(s):

S. N. Rampersad

Keyword(s):

Fusarium Solani ◽

Cucurbita Pepo ◽

Morphological Characteristics ◽

Soft Rot ◽

The United States ◽

Fruit Rot ◽

Laboratory Manual ◽

First Report ◽

Pathogenicity Tests ◽

Negative Controls

Trinidad is a major exporter of pumpkins (Cucurbita pepo L.) to other Caribbean countries, Canada, and the United States. Producers and exporters have reported 50 to 80% yield losses because of soft rot and overnight collapse of fruit at the pre- and postharvest stages. Severe fruit rot occurred in fields in Victoria County in South Trinidad between April and May 2006 (mid-to-late dry season) with an increase in the severity and number of affected fruit in the rainy season (July to December). Symptoms began as water-soaked lesions on the fruit of any age at the point of contact with the soil. The disease progressed to a soft rot with leakage and whole fruit collapse. A dark brown, soft decay also developed at the base of the main vines. Fusarium solani was isolated on selective fusarium agar and potato dextrose agar (PDA) (1) after 7 to 10 days of incubation at 25°C. The pathogen was identified by morphological characteristics and pathogenicity tests. Colonies were fast growing with white aerial mycelia and a cream color on the reverse side; hyphae were septate and hyaline, conidiophores were unbranched, and microconidia were abundant, thin walled, hyaline, fusiform to ovoid, generally one to two celled, and 8 to 10 × 2 to 4 μm. Macroconidia were hyaline, two to three celled, moderately curved, thick walled, and 25 to 30 × 4 to 6 μm. Pathogenicity tests for 10 isolates were conducted on 2-week-old pumpkin seedlings (cv. Jamaican squash; seven plants per isolate) and mature pumpkin fruit (2). Briefly, seedlings were inoculated by dipping their roots in a spore suspension (1 × 104 spores per ml) for 20 min. The plants were repotted in sterile potting soil. For negative controls, plant roots were dipped in sterile water. After the rind of fruit was swabbed with 70% ethanol followed by three rinses with sterile distilled water, 0.4-cm-diameter agar plugs of the isolates were inserted into wounds made with a sterile 1-cm-diameter borer. Sterile PDA plugs served as negative controls. Fruit were placed in sealed, clear, plastic bags. Inoculated plants and fruit were placed on greenhouse benches (30 to 32°C day and 25 to 27°C night temperatures) and monitored over a 30-day period. Tests were repeated once. Inoculated fruit developed a brown, spongy lesion that expanded from the initial wound site over a period of approximately 17 days after inoculation. White mycelia grew diffusely over the lesion. Inoculated plants developed yellow and finally necrotic leaves and lesions developed on stems at the soil line approximately 21 days after inoculation. No symptoms developed on the control plants. The fungus was reisolated from symptomatic tissue, fulfilling Koch's postulates. To my knowledge, this is the first report of Fusarium fruit rot of pumpkin in Trinidad. References: (1) J. Leslie and B. Summerell. Page 1 in: The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, 2006. (2) W. H. Elmer. Plant Dis. 80:131, 1996.

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First Report of Fludioxonil Resistance in Botrytis cinerea from a Blackberry Field in Georgia

Plant Disease ◽

10.1094/pdis-10-13-1020-pdn ◽

2014 ◽

Vol 98 (6) ◽

pp. 848-848 ◽

Cited By ~ 6

Author(s):

D. Fernández-Ortuño ◽

A. Grabke ◽

P. K. Bryson ◽

E. D. Beasley ◽

L. A. Fall ◽

...

Keyword(s):

South Carolina ◽

Botrytis Cinerea ◽

Crop Protection ◽

The United States ◽

Gray Mold ◽

Resistant Isolate ◽

Malt Extract ◽

First Report ◽

Control Fruit ◽

Lesion Diameter

Botrytis cinerea Pers. is an important plant-pathogenic fungi responsible for gray mold on more than 230 plant species worldwide, including blackberry (Rubus). One of the main strategies to control the disease involves the application of different classes of fungicides. The phenylpyrrole fludioxonil is currently marketed in combination with the anilinopyrimidine cyprodinil as Switch 62.5WG (Syngenta Crop Protection Inc., Greensboro, NC) for gray mold control. In August 2013, blackberries affected with symptoms resembling gray mold were collected from a field located in Berrien County (Georgia), where Switch 62.5WG had been used extensively over the last 5 years. Three single-spore isolates, each from a different fruit, were obtained and identified as B. cinerea on the basis of morphology and confirmed by a 238-bp PCR amplification product obtained with primer set G3PDH-F1 (5′-GGACCCGAGCTAATTTATGTCACGT-3′), G3PDH-F2 (5′-GGGTGTCAACAACGAGACCTACACT-3′), and G3PDH-R (5′-ACCGGTGCTCGATGGGATGAT-3′). In vitro sensitivity to fludioxonil (Scholar SC, Syngenta) was determined on 1% malt extract agar (MEA) using a conidial germination assay as previously described (4). One isolate was moderately resistant due to growth on medium amended with the discriminatory dose of 0.1 μg/ml fludioxonil and residual growth at 10 μg/ml (4). To assess performance of fludioxonil in detached fruit assays, commercially grown strawberries (24 in total for each isolate and treatment) were rinsed with water, dried, and sprayed 4 h prior to inoculation with either water (control fruit) or 2.5 ml/liter of Scholar SC to runoff using a hand mister. Scholar SC was used because fludioxonil was the sole active ingredient in this product and strawberries were used because latent infections in fresh blackberry fruit interfered with inoculation experiments. This dose reflects the rate recommended for postharvest gray mold control according to the Scholar label. Fruit was stab-wounded with a sterile syringe and inoculated with a 30-μl droplet of conidia suspension (106 spores/ml) of the two sensitive or the resistant isolate. After inoculation, the fruit were kept at 22°C for 4 days. The sensitive isolates developed gray mold on non-treated (2.7 cm lesion diameter) but not on Scholar SC-treated fruit (0.0 cm lesion diameter). The resistant isolate developed gray mold disease on the water-treated control fruit (2.5 cm lesion diameter) and the fungicide-treated fruit (1.8 cm lesion diameter). EC50 values were determined in microtiter assays as described previously (3) using the concentrations of 0.01, 0.04, 0.12, 0.37, 1.1, 3.3, and 10 μg/ml fludioxonil. Values were 0.02 and 0.05 μg/ml for the two sensitive isolates and 3.15 μg/ml for the resistant isolate. All experiments were performed twice. This is the first report of fludioxonil resistance in B. cinerea from blackberry in Georgia. Prior to this study, resistance to fludioxonil in B. cinerea was reported in France, Germany, and only a few states in the United States including Maryland, South Carolina, Virginia, and Washington (1,2). The emergence of resistance to fludioxonil emphasizes the importance of resistance management strategies. References: (1) D. Fernández-Ortuño et al. Plant Dis. 97:848, 2013. (2) D. Fernández-Ortuño et al. Plant Dis. 98:692, 2013. (3) M. Kretschmer et al. PLOS Pathog. 5:e1000696, 2009. (4) R. W. S. Weber and M. Hahn. J. Plant Dis. Prot. 118:17, 2011.

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First Report of Fludioxonil Resistance in Botrytis cinerea, the Causal Agent of Gray Mold, from Strawberry Fields in Maryland and South Carolina

Plant Disease ◽

10.1094/pdis-08-13-0875-pdn ◽

2014 ◽

Vol 98 (5) ◽

pp. 692-692 ◽

Cited By ~ 8

Author(s):

D. Fernández-Ortuño ◽

A. Grabke ◽

P. K. Bryson ◽

R. J. Rouse ◽

P. Rollins ◽

...

Keyword(s):

United States ◽

South Carolina ◽

Botrytis Cinerea ◽

Crop Protection ◽

The United States ◽

Gray Mold ◽

Causal Agent ◽

First Report ◽

Lesion Diameter

Botrytis cinerea Pers. is the causal agent of gray mold and one of the most economically important plant-pathogenic fungi affecting strawberry (Fragaria × ananassa). Control of gray mold mainly depends on the use of site-specific fungicides, including the phenylpyrrole fludioxonil. This fungicide is currently registered in combination with cyprodinil in form of Switch 62.5WG (Syngenta Crop Protection, Greensboro, NC) for gray mold control of small fruits in the United States. In June 2013, strawberries affected with symptoms resembling gray mold were observed despite the application of Switch in one field located in Federalsburg, MD, and one located near Chesnee, SC. Ten single-spore isolates, each from a different fruit, were obtained from each location and confirmed to be B. cinerea using cultural and molecular tools as described previously (3). In vitro sensitivity to fludioxonil (Scholar SC, 20.4% [v/v] active ingredient, Syngenta Crop Protection, Greensboro, NC) was determined using a conidial germination assay as previously described (4). Eight of the 20 isolates (six from Maryland and two from South Carolina) were moderately resistant to fludioxonil, i.e., they grew on medium amended with 0.1 μg/ml fludixonil and showed residual growth at 10 μg/ml (4). The in vitro assay was repeated obtaining the same results. To assess in vivo sensitivity on fungicide-treated fruit, commercially grown strawberries were rinsed with water, dried, and sprayed 4 h prior to inoculation with either water or 2.5 ml/liter of Scholar SC to runoff using a hand mister. Fruit was stab-wounded with a sterile syringe and inoculated with a 30-μl droplet of conidia suspension (106 spores/ml) of either two sensitive or four resistant isolates (two isolates from Maryland and two isolates from South Carolina). Each isolate/treatment combination consisted of 24 mature but still firm strawberry fruit with three 8-fruit replicates. The fruit were kept at 22°C and lesion diameters were measured after 4 days of inoculation. The sensitive isolates developed gray mold symptoms on nontreated (2.5 cm lesion diameter) but not on Scholar SC-treated fruit. The resistant isolates developed gray mold on both, the water-treated control (2.3 cm lesion diameter), and the fungicide-treated fruit (1.8 cm lesion diameter). The experiment was performed twice. To our knowledge this is the first report of fludioxonil resistance in B. cinerea from strawberry fields in Maryland and South Carolina. Resistance to fludioxonil is still rare in the United States and has only been reported in B. cinerea isolates from a Virginia strawberry field (1). The increase in occurrence of resistance to fludioxonil may be a result of increased use of Switch following reports of resistance to other chemical classes in this pathogen in southern strawberry fields (2). References: (1) D. Fernández-Ortuño et al. Plant Dis. 97:848, 2013. (2) D. Fernández-Ortuño et al. Plant Dis. 96:1198, 2012. (3) D. Fernández-Ortuño et al. Plant Dis. 95:1482, 2011. (4) R. W. S. Weber and M. Hahn. J. Plant Dis. Prot. 118:17, 2011.

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