First Report of Lasiodiplodia theobromae and Neofusicoccum parvum/N. ribis species Complex Causing Fruit Rot on Strawberry in the United States

Persimmon trees are important for their fruit as well as their colorful fruit and foliage in the fall. Persimmon fruit (Japanese persimmon, Diospyros kaki cv. Fuyu) were collected in November 2008 from a tree in Windsor, NC, located in the Coastal Plain. Fruit were not symptomatic on the tree but developed dark lesions after harvest. Isolations from six fruit yielded seven isolates of Colletotrichum acutatum J. H. Simmonds. After incubation at 25°C under continuous light for 15 days on potato dextrose agar (PDA), all isolates had gray aerial mycelium, but the inverse sides of the plates of six isolates were maroon and one was beige. Masses of salmon-colored conidia were formed first in the center of the colonies, then were observed scattered across the colonies in older cultures. Conidia were hyaline, one-celled, elliptic with one or both ends pointed, and measured 8.1 to 16.3 × 3.1 to 5 μm. Setae and sclerotia were not observed. There were also dark structures measuring 1 to 10 mm that were partially embedded in the agar that contained conidia. Cultural and conidial characteristics of the isolates were similar to those of C. acutatum (3). PCR amplification was performed with the species-specific primer pair CaInt2/ITS4 (2) and genomic DNA from the original isolates and isolates obtained from inoculated fruit. An amplification product of approximately 490 bp, which is specific for C. acutatum, was observed. To fulfill Koch's postulates, persimmon fruit obtained from the grocery store were surface disinfested with 0.5% sodium hypochlorite and sterile filter paper disks dipped in conidial suspensions (1 × 105 conidia/ml) of two C. acutatum isolates (maroon and beige reverse) or sterile, deionized water were placed on the fruit. Three fruit were inoculated per treatment and the disks were placed on four locations on each fruit. Parafilm was wrapped around the diameter of the fruit to keep the filter paper disks moist and in place. Fruit were placed in moist chambers and incubated at 25°C. After 3 days, the Parafilm was removed and the fruit returned to the moist chambers. Small, dark lesions were observed on fruit inoculated with each isolate of C. acutatum when the filter paper disks were removed. Ten days after inoculation, dark lesions and acervuli with salmon-colored masses of conidia were observed on fruit inoculated with both isolates of C. acutatum and the fruit were soft. After 12 days, there were abundant masses of conidia and the inoculated areas were decayed. Control fruit remained firm and did not develop symptoms. Cultures obtained from the fruit and the conidia produced were typical of the isolates used to inoculate the fruit. C. acutatum has been reported to cause fruit rot on persimmon fruit in New Zealand (1). To our knowledge, this is the first report of C. acutatum on persimmon fruit in the United States. References: (1) R. Lardner et al. Mycol. Res. 103:275, 1999. (2) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (3) B. C. Sutton. Page 523 in: Coelomycetes. Commonwealth Agricultural Bureaux, Great Britain. 1980.

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First Report of Anthracnose Fruit Rot Caused by Colletotrichum fioriniae on Red Raspberry (Rubus idaeus) in the Mid-Atlantic Region of the United States

Plant Disease ◽

10.1094/pdis-10-19-2256-pdn ◽

2020 ◽

Vol 104 (6) ◽

pp. 1855

Author(s):

A. Schoeneberg ◽

M.-J. Hu

Keyword(s):

United States ◽

The United States ◽

Rubus Idaeus ◽

Fruit Rot ◽

Red Raspberry ◽

Atlantic Region ◽

First Report

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First Report of Stem Canker of Goldenrain Tree Caused by Lasiodiplodia theobromae in Tennessee and the United States

Plant Disease ◽

10.1094/pdis-05-20-0963-pdn ◽

2020 ◽

Vol 104 (11) ◽

pp. 3062-3062

Author(s):

F. Baysal-Gurel ◽

F. A. Avin ◽

Cansu Oksel ◽

T. Simmons

Keyword(s):

United States ◽

Stem Canker ◽

The United States ◽

Lasiodiplodia Theobromae ◽

First Report

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First Report of Neofusicoccum parvum Causing Dieback and Canker Disease on Hemp in the United States

Plant Disease ◽

10.1094/pdis-03-20-0486-pdn ◽

2020 ◽

Vol 104 (11) ◽

pp. 3075

Author(s):

C. Feng ◽

M. I. Villarroel-Zeballos ◽

P. F. Ficheux ◽

H. Zima ◽

B. D. S. Dhillon ◽

...

Keyword(s):

United States ◽

The United States ◽

Neofusicoccum Parvum ◽

Canker Disease ◽

First Report

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First Report of Postharvest Fruit Rot in Persimmon Caused by Phacidiopycnis washingtonensis in Italy

Plant Disease ◽

10.1094/pdis-94-6-0788b ◽

2010 ◽

Vol 94 (6) ◽

pp. 788-788 ◽

Cited By ~ 2

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. T. Amatulli ◽

M. L. Gullino

Keyword(s):

United States ◽

Its Region ◽

The United States ◽

Fruit Rot ◽

Diospyros Kaki ◽

Pathogenicity Test ◽

Conidial Suspension ◽

First Report ◽

Pathogenicity Tests ◽

Phacidiopycnis Washingtonensis

Persimmon (Diospyros kaki L.) is widely grown in Italy, the leading producer in Europe. In the fall of 2009, a previously unknown rot was observed on 3% of fruit stored at temperatures between 5 and 15°C in Torino Province (northern Italy). The decayed area was elliptical, firm, and appeared light brown to dark olive-green. It was surrounded by a soft margin. The internal decayed area appeared rotten, brown, and surrounded by bleached tissue. On the decayed tissue, black pycnidia that were partially immersed and up to 0.5 mm in diameter were observed. Light gray conidia produced in the pycnidia were unicellular, ovoid or lacriform, and measured 3.9 to 6.7 × 2.3 to 3.5 (average 5.0 × 2.9) μm. Fragments (approximately 2 mm) were taken from the margin of the internal diseased tissues, cultured on potato dextrose agar (PDA), and incubated at temperatures between 23 and 26°C under alternating light and darkness. Colonies of the fungus initially appeared ash colored and then turned to dark greenish gray. After 14 days of growth, pycnidia and conidia similar to those described on fruit were produced. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 502-bp segment showed a 100% similarity with the sequence of Phacidiopycnis washingtonensis Xiao & J.D. Rogers (GenBank Accession No. AY608648). The nucleotide sequence has been assigned the GenBank Accession No. GU949537. Pathogenicity tests were performed by inoculating three persimmon fruits after surface disinfesting in 1% sodium hypochlorite and wounding. Mycelial disks (10 mm in diameter), obtained from PDA cultures of one strain were placed on wounds. Three control fruits were inoculated with plain PDA. Fruits were incubated at 10 ± 1°C. The first symptoms developed 6 days after the artificial inoculation. After 15 days, the rot was very evident and P. washingtonensis was consistently reisolated. Noninoculated fruit remained healthy. The pathogenicity test was performed twice. Since P. washingtonensis was first identified in the United States on decayed apples (2), ‘Fuji’, ‘Gala’, ‘Golden Delicious’, ‘Granny Smith’, ‘Red Chief’, and ‘Stark Delicious’, apple fruits also were artificially inoculated with a conidial suspension (1 × 106 CFU/ml) of the pathogen obtained from PDA cultures. For each cultivar, three surface-disinfested fruit were wounded and inoculated, while three others served as mock-inoculated (sterile water) controls. Fruits were stored at temperatures ranging from 10 to 15°C. First symptoms appeared after 7 days on all the inoculated apples. After 14 days, rot was evident on all fruit inoculated with the fungus, and P. washingtonensis was consistently reisolated. Controls remained symptomless. To our knowledge, this is the first report of the presence of P. washingtonensis on persimmon in Italy, as well as worldwide. The occurrence of postharvest fruit rot on apple caused by P. washingtonensis was recently described in the United States (3). In Italy, the economic importance of the disease on persimmon fruit is currently limited, although the pathogen could represent a risk for apple. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) Y. K. Kim and C. L. Xiao. Plant Dis. 90:1376, 2006. (3) C. L. Xiao et al. Mycologia 97:473, 2005.

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First Report of Phytophthora syringae Causing Rot on Apples in Cold Storage in the United States

Plant Disease ◽

10.1094/pdis.2002.86.6.693b ◽

2002 ◽

Vol 86 (6) ◽

pp. 693-693 ◽

Cited By ~ 2

Author(s):

R. A. Spotts ◽

G. G. Grove

Keyword(s):

United States ◽

Cold Storage ◽

The United States ◽

River Valley ◽

Fruit Rot ◽

Commonwealth Mycological Institute ◽

Postharvest Diseases ◽

First Report ◽

Postharvest Decay ◽

Wide Range

A decay of ‘Granny Smith’ apples (Malus domestica Borkh.) was observed in 1988, 1990, and 1991 on fruit grown in the lower Hood River Valley of Oregon and stored at 0°C. Harvested fruit were drenched with thiabendazole and stored in October in all years. In mid-November, fruit were sized, drenched with sodium hypochlorite, and returned to cold storage. Decay was observed in January when fruit were removed from cold storage, sorted, and packed. Decayed areas were light brown and firm with a slightly indefinite margin. Losses were less than 1% of fruit packed. Diseased fruit were surface-disinfested with 95% ethanol, and tissue pieces were transferred aseptically to potato dextrose agar acidified with lactic acid and incubated at approximately 22°C. The fungus consistently isolated was identified as Phytophthora syringae (Kleb.) Kleb. based on morphological characters (3). Sporangia were persistent and averaged 60 μm long (range 59 to 69) × 40 μm wide (range 37 to 43). Antheridia were paragynous, and oospores averaged 37 μm (range 31 to 46). ‘Golden Delicious’, ‘Granny Smith’, and ‘Gala’ apples were inoculated with mycelial plugs from a 7-day-old culture of P. syringae and incubated 12 days at 5°C and 7 to 12 days at 22°C. Twenty fruit of each cultivar were used—ten were inoculated, and ten uninoculated fruit served as controls. Lesions developed on all inoculated fruit but not on uninoculated controls. Lesions were spherical, chocolate brown, and firm with no evidence of external mycelia. Lesion morphology was similar on all cultivars. P. syringae was reisolated from lesion margins of all infected fruit. This postharvest decay of apples has not been observed in the Hood River Valley since 1991. Fruit rot of apples caused by P. syringae is known in Canada (1) and is common in the United Kingdom (2), but has not been reported previously in the United States. To our knowledge, this is the first report of postharvest decay of apples by P. syringae in the United States. References: (1) R. G. Ross and C. O. Gourley. Can. Plant Dis. Surv. 49:33, 1969. (2) A. L. Snowdon. A Color Atlas of Postharvest Diseases. CRC Press, Inc., Boca Raton, FL, 1990. (3) G. M. Waterhouse. The Genus Phytophthora. Misc. Publ. 12. The Commonwealth Mycological Institute, Kew, Surrey, England, 1956.

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First Report of Colletotrichum scovillei Causing Anthracnose Fruit Rot on Pepper in South Carolina, United States

Plant Disease ◽

10.1094/pdis-08-20-1656-pdn ◽

2020 ◽

Author(s):

Sean M Toporek ◽

Anthony P. Keinath

Keyword(s):

United States ◽

South Carolina ◽

Average Length ◽

The United States ◽

Fruit Rot ◽

Lesion Length ◽

Pathogenicity Test ◽

Conidial Suspension ◽

Accession Number ◽

First Report

Anthracnose fruit rot caused by various Colletotrichum spp. is a serious disease for pepper (Capsicum annuum) growers, resulting in extensive fruit loss (Harp et al. 2008). Samples of five pepper fruits were obtained from two commercial farms in Lexington and Pickens counties, South Carolina, in August and September 2019, respectively. All fruits had two or more soft, sunken lesions covered with salmon-colored spore masses. Pieces of diseased tissue cut from the margins of lesions were surface disinfested in 0.6% sodium hypochlorite, rinsed in sterile deionized water, blotted dry, and placed on one-quarter-strength potato dextrose agar (PDA/4) amended with 100 mg chloramphenicol, 100 mg streptomycin sulfate, and 60.5 mg mefenoxam (0.25 ml Ridomil Gold EC) per liter. Two isolates of Colletotrichum sp. per fruit were preserved on dried filter paper and stored at 10º C. One additional isolate of Colletotrichum sp. had been collected from a jalapeño pepper fruit on a farm in Charleston County, South Carolina, in 1997. Colony morphology of three isolates, one per county, on Spezieller Nährstoffarmer Agar (SNA) was pale grey with a faint orange tint. All isolates readily produced conidia on SNA with an average length of 16.4 μm (std. dev. = 1.8 μm) and a width of 2.2 μm (std. dev. = 0.2 μm). Conidia were hyaline, smooth, straight, aseptate, cylindrical to fusiform with one or both ends slightly acute or round, matching the description of C. scovillei (Damm et al. 2012). The glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-tubulin (TUB2) genes from three isolates were amplified and sequenced with the primer pairs GDF1/GDR1 and T1/Bt2b, respectively. Species within the C. acutatum clade can be readily distinguished with GAPDH or TUB2 (Cannon et al. 2012). The GAPDH and TUB2 sequences for all three isolates were 100% similar to each other and strain CBS 126529 (GAPDH accession number JQ948597; TUB2 accession number JQ949918) of C. scovillei (Damm et al. 2012). GAPDH and TUB2 sequences for each isolate were deposited in GenBank under the accessions MT826948–MT826950 and MT826951-MT826953, respectively. A pathogenicity test was conducted on jalapeño pepper fruits by placing a 10-ul droplet of a 5 x 105 conidial suspension of each isolate onto a wound made with a sterile toothpick. Control peppers were mock inoculated with 10 ul sterile distilled water. A humid chamber was prepared by placing moist paper towels on the bottom of a sealed crisper box. Inoculated peppers were placed on upside-down 60 ml plastic condiment cups. Three replicate boxes each containing all four treatments were prepared. The experiment was repeated once. After 7 days in the humid chamber at 26ºC, disease did not develop on control fruits, whereas soft, sunken lesions covered with salmon-colored spores developed on inoculated fruits. Lesions were measured and C. scovillei was re-isolated onto amended PDA/4 as previously described. Lesion length averaged 15.6 mm (std dev. = 4.1 mm) by 11.5 mm (std dev. = 2.0 mm). Colletotrichum sp. resembling the original isolate were recovered from all inoculated fruit, but not from non-inoculated fruit. C. scovillei has been reported in Brazil in South America and in China, Indonesia, Japan, Malaysia, South Korea, Taiwan, and Thailand in Asia (Farr and Rossman 2020). This is the first report of C. scovillei as the casual organism of anthracnose fruit rot on pepper in South Carolina and the United States.

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First Report of Flower Anthracnose Caused by Colletotrichum karstii in White Phalaenopsis Orchids in the United States

Plant Disease ◽

10.1094/pdis-04-12-0360-pdn ◽

2012 ◽

Vol 96 (8) ◽

pp. 1227-1227 ◽

Cited By ~ 9

Author(s):

I. Jadrane ◽

M. Kornievsky ◽

D. E. Desjardin ◽

Z.-H. He ◽

L. Cai ◽

...

Keyword(s):

United States ◽

Species Complex ◽

The United States ◽

Likelihood Method ◽

Conidial Suspension ◽

Necrotic Tissue ◽

Internal Transcribed Spacer Region ◽

First Report ◽

Whole Plant ◽

Pure Cultures

In October 2010, a Colletotrichum species was isolated from white Phalaenopsis flowers growing in a greenhouse in San Francisco, CA. This Phalaenopsis is a common commercial orchid hybrid generated mostly likely from Phalaenopsis amabilis and P. aphrodite. The white petals showed anthracnose-like lesions where necrotic tissue is surrounded by a ring of green tissue. The green halo tissues around the necrotic tissue contain functional chloroplasts. One-centimeter disks were cut around the necrotic sites and surface-sterilized with 95% ethanol and 0.6% sodium hypochlorite. The disks were placed on potato dextrose agar (PDA) medium to establish cultures. Pure cultures were obtained by subculturing hyphal tips onto fresh PDA plates. The generated colonies had white aerial mycelia and orange conidial mass. The color of the reverse colony varies between colorless and pale orange. Microscopic observations identified the conidia as cylindrical, straight, and rounded at both ends. In addition, the conidia were approximately 15.0 to 18.0 μm long and 5.0 to 6.5 μm in diameter. These observed morphological features suggested that these isolates possessed the same characteristics as previously described for Colletotrichum karstii, a species considered as part of the C. boninense species complex (1). Four putative independent Colletotrichum isolates were recovered (DED9596, DED9597, DED9598, and DED9599). To confirm the Colletotrichum isolates as the causative pathogen, healthy white Phalaenopsis flowers (five total) in a whole plant were sprayed with a conidial suspension (approximately 1.2 × 106 conidia/ml) of the isolates and incubated at 20°C and 100% relative humidity with cycles of 16 h light and 8 h of darkness. Approximately 1 ml of conidial suspension solution was used for each flower. The plants were watered regularly and flowers were sprayed with sterile double-distilled water daily. As negative controls, five flowers in a whole plant were sprayed with water. Fifteen to twenty days after inoculation, lesions started to form on the petals sprayed with the putative Colletotrichum isolates. All controls remained healthy. The Colletotrichum-inoculated flowers remained alive and did not die as a result of the infection. This same experiment was repeated and the same results were obtained. DNA was extracted from the necrotic regions of the petals infected by the pure cultures of the four isolates and used to sequence the 18S rRNA ITS (internal transcribed spacer) region. All four isolates gave identical ITS sequences. Analysis of the obtained representative sequences (GenBank Accession No. JQ277352) suggested that the isolated pathogen as C. karstii. Using the published ITS data for the C. boninense species complex (1), a phylogenetic tree was generated via the maximum likelihood method. This created tree places the isolates in the same group as C. karstii. This type of C. karstii infection in Phalaenopsis orchid petals was not documented in the U.S. before, although it has been reported in China and Thailand (2). To our knowledge, this is the first report of infection and green island formation caused by C. karstii on orchid flower in the United States. References: (1) Damm et al. Studies in Mycology 73:1, 2012. (2) Yang et al. Cryptogamie Mycologie 32:229, 2011.

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First Report of Fruit Rot of Ridge Gourd (Luffa acutangula) Caused by Sclerotium rolfsii

Plant Health Progress ◽

10.1094/php-br-15-0048 ◽

2016 ◽

Vol 17 (1) ◽

pp. 18-19

Author(s):

Chandrasekar S. Kousik ◽

Jennifer Ikerd ◽

Mihir Mandal

Keyword(s):

United States ◽

Sclerotium Rolfsii ◽

The United States ◽

Fruit Rot ◽

Small Scale ◽

First Report ◽

Athelia Rolfsii ◽

History Of ◽

Sclerotium Rot ◽

Luffa Acutangula

Ridge gourd is a specialty cucurbit vegetable cultivated in the United States on a small scale for select markets. We report the infection of ridge gourd fruit by Sclerotium rolfsii (teleomorph: Athelia rolfsii). This appears to be the first report of Sclerotium rot of ridge gourd. In fields with history of S. rolfsii, the gourds should be grown on trellis to prevent fruit contact with wet soil. Several fungicides are available to manage S. rolfsii and may have to be applied if and when needed. Accepted for publication 12 January 2016. Published 14 January 2016.

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First Report of Postharvest Fruit Rot in Avocado (Persea americana) Caused by Lasiodiplodia theobromae in Italy

Plant Disease ◽

10.1094/pdis-10-11-0886 ◽

2012 ◽

Vol 96 (3) ◽

pp. 460-460 ◽

Cited By ~ 6

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. T. Amatulli ◽

J. Cardinale ◽

M. L. Gullino

Keyword(s):

Plant Pathogens ◽

Morphological Characteristics ◽

The United States ◽

Disease Diagnosis ◽

Persea Americana ◽

Fruit Rot ◽

Pathogenicity Test ◽

Lasiodiplodia Theobromae ◽

First Report ◽

Pathogenicity Tests

Avocado (Persea americana Mill.) is grown in some areas of southern Italy. In spring 2011, a previously unknown rot was observed on fruit that was marketed in Torino (northern Italy). The decayed area started from the stalk, appeared irregular and soft, and was surrounded by a dark brown margin. The internal decayed area appeared rotten, brown, and surrounded by bleached tissue. Fragments (approximately 3 mm) were taken from the margin of the internal diseased tissues, cultured on potato dextrose agar (PDA), and incubated at temperatures between 21 and 25°C under alternating conditions of light and dark. Colonies of the fungus initially appeared whitish, later turning mouse gray to black. Mature mycelium was septate and produced a dark pigment. The fungus, grown on oat agar (2) and incubated at temperatures between 21 and 25°C under alternating light and darkness, produced grayish colonies with a fluffy aerial mycelium that became dark with age and produced black pigments. After 18 days of incubation, such colonies produced pycnidia aggregated into stromatic masses, emerging from decayed tissues, and up to 3 to 4 mm in diameter. Conidia produced in the pycnidia were initially unicellular, hyaline, granulose, ovoid to ellipsoidal, and measured 20.8 to 26.9 × 12.5 to 16.1 (average 24.4 × 13.5) μm. After 7 days, mature conidia became darker, uniseptate, and longitudinally striate. Paraphyses produced within the tissues of pycnidia were hyaline, cylindrical, nonseptate, and up to 63 μm long. Morphological characteristics of mycelia, pycnidia, and conidia observed with a light microscope permitted identify of the fungus as Lasiodiplodia theobromae (3). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 488-bp segment showed a 100% similarity with the corresponding sequence (GenBank Accession No. GQ502453) of L. theobromae Pat. Griffon & Maubl. The nucleotide sequence of the strain used for pathogenicity tests was submitted to GenBank (Accession No. JN849098). Pathogenicity tests were performed by inoculating 10 avocado fruits after surface disinfesting in 1% sodium hypochlorite and then wounding. Mycelial disks (8 mm in diameter) obtained from PDA cultures of one strain were placed on wounds. Ten control fruits were inoculated with plain PDA. Fruits were incubated at 15 ± 1°C. The first symptoms developed 4 days after the artificial inoculation. After 7 days, the rot was evident and L. theobromae was consistently reisolated. Noninoculated fruit remained healthy. The pathogenicity test was performed twice. To our knowledge, this is the first report of the presence of L. theobromae causing postharvest fruit rot on avocado in Italy, as well as in Europe. The occurrence of postharvest fruit rot on avocado caused by L. theobromae was described in many avocado-producing areas such as the United States (4), South Africa, and Israel. In Italy, the economic importance of avocado cultivation is currently limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2). P. Narayanasamy. Microbial Plant Pathogens. Detection and Disease Diagnosis: Fungal Pathogens. Springer, Dordrecht, 2011. (3) E. Punithalingam. Sheet 519. CMI Description of Fungi and bacteria, 1976. (4) H. E. Stevens and R. B. Piper. Circular No. 582, USDA, 1941.

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