scholarly journals First Report of Fruit Rot on Hylocereus undatus Caused by Bipolaris cactivora in South Florida

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1506-1506 ◽  
Author(s):  
T. L. B. Tarnowski ◽  
A. J. Palmateer ◽  
J. H. Crane
Keyword(s):  
Dna Sequences ◽  
The United States ◽  
South Florida ◽  
Plant Diseases ◽  
Fruit Rot ◽  
Mature Plant ◽  
Commonwealth Mycological Institute ◽  
Tropical Fruit ◽  
First Report ◽  
Hylocereus Undatus

Pitahaya (Hylocereus undatus (Haw.) Britton & Rose), a cactus grown for its edible fruit, is gaining popularity in South Florida as part of the specialty tropical fruit market. In July 2009, flowers and fruit were discovered with an uncharacterized rot. Small, circular, light brown, depressed lesions expanded to form large areas of rot on flowers and fruit in 7 to 10 days. The lesions produced large amounts of dark fungal spores. Single-spore isolates were identified morphologically and by aligning internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (gpd) DNA sequences from the isolates with previously published sequences of Bipolaris, Drechslera, and Cochliobolus species. Conidia from the dark, blackish brown colonies were formed at the tips of pale golden brown, straight to flexuous conidiophores, 99 (184) 313 × 3 (6) 8 μm and slightly swollen at the apex and base. Conidia were pale-to-medium golden brown, smooth and clavate with a protuberant hilum, 24 (40) 51 × 9 (10) 13 μm, and two to four distoseptate. The isolates closely match descriptions of Bipolaris cactivora (= Drechslera cactivora) (3,4), although isolates from pitahaya had smaller conidia (30 to 65 μm) than previously reported. Conidial characteristics from a B. cactivora herbarium specimen BPI 431621 (U.S. National Fungus Collections) closely matched (29 (36) 50 × 8 (9) 11 μm, two to four distoseptate) our isolates. ITS (GenBank Accession Nox. HM598677–79) sequences aligned most closely (99.7% homology) with another B. cactivora isolate from China (GU390882), and both ITS and gpd (GenBank Accession Nos. HM598680–82) sequences indicate a close relationship to Bipolaris indica. Wounded or nonwounded mature pitahaya fruit and mature stems were inoculated with either a mycelia plug or a 15-μl 0.3% agar drop containing 105 conidia ml–1. Lesion diameters were measured after 7 days at 25°C, the fungus was reisolated on potato dextrose agar (PDA) and its identity was confirmed. Mean lesion diameters on mature fruit were 6.0 to 10.8 mm, depending on the inoculation method, and sporulation began 6 days after inoculation. On mature plant stems, wound-inoculated treatments formed 1.8 to 3.4 mm lesions, but nonwounded inoculations and controls were negative. Lesions were light tan, circular, and did not sporulate. To our knowledge, this is the first report of fruit rot caused by B. cactivora on pitahaya in Florida. The same pathogen causes stem rot of the Cactaceae in Europe and the United States (2) and a fruit rot on pitahaya in Japan (4). In Florida, it has been reported as causing a leaf spot on Portulaca oleracea (1). Our results indicate that B. cactivora causes flower and fruit rot on pitahaya, but does not seriously affect mature plant stems. The flower rot does not appear to significantly increase incidence but may provide inoculum for the fruit rot. The high incidence of fruit rot affecting commercial operations in Miami-Dade County over the past 2 years requires an effective disease management strategy. References: (1) S. A. Alfieri, Jr. et al. Bull. 14. Index of Plant Diseases in Florida (Revised). Florida Dep. Agric. Consumer Serv., Div. Plant Ind., 1984. (2) R. D. Durbin et al. Phytopathology 45:509, 1955. (3) M. B. Ellis. Page 432 in: Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England. 1971. (4) S. Taba et al. J. Gen. Plant Pathol. 73:374, 2007.

scholarly journals First Report of Lasiodiplodia Fruit Rot of Jackfruit in Taiwan

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1137-1137 ◽  
Author(s):  
H. F. Ni ◽  
R. S. Chen ◽  
S. F. Chang ◽  
H. R. Yang
Keyword(s):  
Early Stage ◽  
Plant Diseases ◽  
Fruit Rot ◽  
Commonwealth Mycological Institute ◽  
Tropical Fruit ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Median Septum ◽  
Agar Plug ◽  
Diseased Fruit

Jackfruit (Artocarpus heterophyllus Lam.) is a tropical fruit that is native to India. Five diseases, including Rhizopus fruit rot and anthracnose fruit rot, have been recorded in Taiwan (2). In 2003, brown lesions were observed on mature or harvested fruits at the Chiayi Agricultural Experiment Branch. The disease caused fruits to collapse and was easily distinguished from anthracnose and Rhizopus fruit rot. In the field, Rhizopus fruit rot was characterized by black flocci sporangia and mycelia covering the flowers and young fruits. Lasiodiplodia fruit rot often occurred on mature or wounded fruit and diseased fruit were covered with gray or black flat mycelia under humid conditions. In the early stage of Lasiodiplodia fruit rot, tiny yellow-brown lesions appeared on the peel. The lesions could rapidly expand to 10 cm in diameter within 5 days and became dark brown with a light margin. The rot symptoms progressed quickly from the peel surface into the sarcocarps that eventually turned black and soft. A fungus was isolated from the margin of the lesions and cultured on acidified potato dextrose agar (PDA) (pH 3.8). The morphology of the fungus was similar to Lasiodiplodia theobromae (Pat.) Griff. & Maubl. (synonym Botryodiplodia theobromae Pat.), which causes the stem-end rot of mango, papaya, and banana in Taiwan. The fungus grew well and produced pycnidia and conidia on PDA. Young conidia were ovate, hyaline, and thin walled without septa. Mature conidia (20 to 28 × 12 to 15 μm) were dark brown and thick walled with one median septum and longitudinal striations. The internal transcribed spacer (ITS) sequence of ribosomal DNA of this fungus was submitted to GenBank (Accession No. EU 407235) and showed 100% sequence identity with that of Botryosphaeria rhodina (anamorph Lasiodiplodia theobromae; GenBank Accession No. DQ458890). On the basis of morphological and molecular criteria, the fungus was identified as L. theobromae (1). Three healthy jackfruit fruits were wounded and inoculated with 2 × 2 mm mycelial agar plugs of the fungus from a monoconidial culture. A sterile agar plug was placed on the wounded site as a control. The fruits were kept in a box to maintain high humidity for 2 days at room temperature. Brown lesions were observed on all inoculated sites 6 days post infection. The pathogen was reisolated from the lesions of inoculated fruits, fulfilling Koch's postulate. The experiment was repeated twice. To our knowledge, this is the first report of L. theobromae causing fruit rot of jackfruit in Taiwan. References: (1) B. C. Sutton. The Coelomycetes. Commonwealth Mycological Institute, Kew, UK, 1980. (2) Y. P. Tsai, ed. List of Plant Diseases in Taiwan. 4th ed. Taiwan Phytopathological Society, 2002.

scholarly journals First Report of Colletotrichum capsici Causing Postharvest Anthracnose on Papaya in South Florida

Plant Disease ◽  
2010 ◽  
Vol 94 (8) ◽  
pp. 1065-1065 ◽  
Author(s):  
T. L. B. Tarnowski ◽  
R. C. Ploetz
Keyword(s):  
The United States ◽  
South Florida ◽  
Plant Diseases ◽  
Water Control ◽  
Single Spore ◽  
Tropical Fruit ◽  
Sterile Needle ◽  
Research And Education ◽  
Production Areas ◽  
The University

Postharvest anthracnose of papaya, Carica papaya, is an important disease in most production areas worldwide (2). Colletotrichum gloeosporioides causes two types of anthracnose symptoms on papaya: (i) circular, sunken lesions with pink sporulation; and (ii) sharply defined, reddish brown and sunken lesions, described as ‘chocolate spot’ (2). Colletorichum spp. were isolated from lesions of the first type on papaya fruit from the University of Florida Tropical Research and Education Center, Homestead in December 2007 and from fruit imported from Belize in March 2008 (4). Single-spore isolates were identified using colony morphology and internal transcribed spacer (ITS) and mating type (MAT1-2) sequences. Two taxa were identified in both locations: (i) C. gloeosporioides (MAT1-2; GenBank Nos. GQ925065 and GQ925066) with white-to-gray, fluffy colonies with orange sporulation and straight and cylindrical conidia; and (ii) C. capsici (ITS; GenBank Nos. GU045511 to GU045514) with sparse, fluffy, white colonies with setose acervuli and falcate conidia. In addition, in Florida, a Glomerella sp. (ITS; GenBank Nos. GU045518 and GU045520 to GU045522) was recovered with darkly pigmented colonies that produced fertile perithecia after 7 to 10 days on potato dextrose agar (PDA). In each of three experiments, mature fruit (cv. Caribbean Red) were wounded with a sterile needle and inoculated with a 15-μl drop of 0.3% water agar that contained 105 conidia ml–1 of representative isolates of each taxon. The diameters of developing lesions were measured after 7 days of incubation in the dark at 25°C, and the presence of inoculated isolates was confirmed by their recovery from lesion margins on PDA. In all experiments, C. capsici and C. gloeosporioides produced lesions that were significantly larger than those that were caused by the water control and Glomerella sp. (respectively, approximately 12, 17, 0, and <1 mm in diameter). C. gloeosporioides produced sunken lesions with dark gray centers and pink/gray sporulation, which match those previously described for anthracnose on papaya (2). In contrast, C. capsici produced dark lesions due to copious setae of this pathogen; they resembled C. capsici-induced lesions on papaya that were reported previously from the Yucatan Peninsula (3). C. capsici has also been reported to cause papaya anthracnose in Asia (4), but to our knowledge, this is the first time it has been reported to cause this disease in Florida. Since it was also recovered from fruit that were imported from Belize, it probably causes anthracnose of papaya in that country as well. Another falcate-spored species, C. falcatum, was recovered from rotted papaya fruit in Texas (1). The Glomerella sp. was recovered previously from other hosts as an endophyte and causes anthracnose lesions on passionfruit (4). However, its role as a pathogen on papaya is uncertain since it was not pathogenic in the current work; the isolates that were recovered from papaya lesions may have colonized lesions that were caused by C. capsici and C. gloeosporioides. References: (1) Anonymous. Index of Plant Diseases in the United States. U.S. Dept. of Agric. Handb. No. 165. Washington, D.C., 1960. (2) D. M. Persley and R. C. Ploetz. Page 373 in: Diseases of Tropical Fruit Crops. R. C. Ploetz, ed. CABI Publishing. Wallingford, UK, 2003. (3) R. Tapia-Tussell et al. Mol Biotechnol 40:293, 2008. (4) T. L. Tarnowski. Ph.D. diss. University Florida, Gainesville, 2009.

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

Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 693-693 ◽  
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.

scholarly journals First Report of Lasmenia sp. and Two Species of Gliocephalotrichum on Rambutan in Hawaii

Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 71-71 ◽  
Author(s):  
K. A. Nishijima ◽  
P. A. Follett ◽  
B. C. Bushe ◽  
M. A. Nagao
Keyword(s):  
The United States ◽  
Psidium Guajava ◽  
Fruit Rot ◽  
Fluorescent Light ◽  
Tropical Fruit ◽  
Centraalbureau Voor ◽  
First Report ◽  
Culture Characteristics ◽  
Decaying Wood ◽  
Branch Dieback

Rambutan (Nephelium lappaceum L.) is a tropical fruit grown in Hawaii for the exotic fruit market. Fruit rot was observed periodically during 1998 and 1999 from two islands, Hawaii and Kauai, and severe fruit rot was observed during 2000 in orchards in Kurtistown and Papaikou on Hawaii. Symptoms were characterized by brown-to-black, water-soaked lesions on the fruit surface that progressed to blackening and drying of the pericarp, which often split and exposed the aril (flesh). In certain cultivars, immature, small green fruits were totally mummified. Rambutan trees with high incidence of fruit rot also showed symptoms of branch dieback and leaf spot. Lasmenia sp. Speg. sensu Sutton, identified by Centraalbureau voor Schimmelcultures (Baarn, the Netherlands), was isolated from infected fruit and necrotic leaves. Also associated with some of the fruit rot and dieback symptoms were Gliocephalotrichum simplex (J.A. Meyer) B. Wiley & E. Simmons, and G. bulbilium J.J. Ellis & Hesseltine. G. simplex was isolated from infected fruit, and G. bulbilium was isolated from discolored vascular tissues and infected fruit. Identification of species of Gliocephalotrichum was based on characteristics of conidiophores, sterile hairs, and chlamydospores (1,4). Culture characteristics were distinctive on potato dextrose agar (PDA), where the mycelium of G. bulbilium was light orange (peach) without reverse color, while G. simplex was golden-brown to grayish-yellow with dark brown reverse color. Both species produced a fruity odor after 6 days on PDA. In pathogenicity tests, healthy, washed rambutan fruits were wounded, inoculated with 30 μl of sterile distilled water (SDW) or a fungus spore suspension (105 to 106 spores per ml), and incubated in humidity chambers at room temperature (22°C) under continuous fluorescent light. Lasmenia sp. (strain KN-F99-1), G. simplex (strain KN-F2000-1), and G. bulbilium (strains KN-F2001-1 and KN-F2001-2) produced fruit rot symptoms on inoculated fruit and were reisolated from fruit with typical symptoms, fulfilling Koch's postulates. Controls (inoculated with SDW) had lower incidence or developed less severe symptoms than the fungus treatments. Inoculation tests were conducted at least twice. To our knowledge, this is the first report of Lasmenia sp. in Hawaii and the first report of the genus Gliocephalotrichum on rambutan in Hawaii. These pathogens are potentially economically important to rambutan in Hawaii. G. bulbilium has been reported previously on decaying wood of guava (Psidium guajava L.) in Hawaii (2), and the fungus causes field and postharvest rots of rambutan fruit in Thailand (3). References: (1) J. J. Ellis and C. W. Hesseltine. Bull. Torrey Bot. Club 89:21, 1962. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (3) N. Visarathanonth and L. L. Ilag. Pages 51–57 in: Rambutan: Fruit Development, Postharvest Physiology and Marketing in ASEAN. ASEAN Food Handling Bureau, Kuala Lumpur, Malaysia, 1987. (4) B. J. Wiley and E. G. Simmons. Mycologia 63:575, 1971.

scholarly journals First Report of Gliocephalotrichum bulbilium Causing Fruit Rot of Posthavest Mangosteen in China

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 994-994 ◽  
Author(s):  
Y. X. Li ◽  
W. X. Chen ◽  
A. Y. Liu ◽  
Q. L. Chen ◽  
S. J. Feng
Keyword(s):  
Its Region ◽  
The United States ◽  
Psidium Guajava ◽  
Morphological Characters ◽  
Fruit Rot ◽  
Diseased Plant ◽  
Garcinia Mangostana ◽  
Single Spore ◽  
Tropical Fruit ◽  
First Report

Mangosteen (Garcinia mangostana L., Guttiferae) is a tropical fruit renowned for its pleasant taste, rich nutrition, and medicinal value. Little research about mangosteen diseases during storage and transport has been reported. In June of 2012, fruit rots on mangosteens imported from Thailand were observed in Guangzhou, China. In infected fruits, pericarps showed an increased firmness, were discolored to deep pink, and the edible aril became brown and rotten. In order to search for the etiological agent of this rot symptom, infected mangosteens were analyzed. Diseased mangosteen tissues were surface-sterilized with 70% alcohol, then with 0.1% HgCl2, dipped in sterilized water three times, and placed onto potato dextrose agar (PDA) at 26°C. The fungi isolated from tissues of the pericarp and aril were similar in morphology and grew rapidly, covering the plate surface (9 mm diameter) after 2 to 3 days of incubation at 26°C. The morphological characters of 10 single-spore isolates were observed. These isolates showed light yellow to light brown fertile colonies on PDA. On corn meal agar (CMA), conidiophores were erect, arising from wide hyphae; they were composed of a basal stipe ending in a penicillate conidiogenous apparatus with directly subtending sterile stipe extensions ranging from 74.5 to 195.0 μm long. Conidia were unicellular, smooth, oblong to elliptical, 6.3 to 8.5 × 2.5 to 3.0 μm, and accumulated in a mucilaginous mass. Chlamydospores were multicellular, dark brown, regular in shape and thick-walled, and 40.0 to 52.5 μm in diameter. On the basis of these morphological characters, these isolates were identified as Gliocephalotrichum bulbilium (2). To confirm the identity of this fungus, genomic DNA of two isolates was extracted, and fragments of ITS region and β-tubulin gene were amplified by PCR, sequenced, and compared with sequences of Gliocephalotrichum species available in NCBI GenBank. Both DNA regions (GenBank Accession Nos. KF716166 and KF716168) had sequence similarities of 99% and 97%, respectively, to other G. bulbilium sequences at GenBank. Pathogenicity tests were conducted on three detached fruits for two isolates. Fruits were inoculated using 5-mm mycelial disks with conidia taken from 3-day-old cultures of G. bulbilium isolate Gb1 and Gb10 grown on PDA. Controls were inoculated with PDA disks only. All treated fruits were kept individually in a humid chamber at 26°C. Tests were repeated twice. Three days after inoculation, white mycelial growth for Gb was observed at inoculation sites. Eight days after inoculation, mycelium of Gb nearly covered the fruit, causing fruit rot, and the pericarp became hard and light in color. The control fruit did not rot. G. bulbilium was re-isolated from diseased plant tissue, thus fulfilling Koch's postulates. G. bulbilium has been reported causing postharvest fruit rot of rambutan (Nephelium lappaceum) and guava (Psidium guajava) in some locations (3,4). Moreover, the fungus caused cranberry fruit rot in the United States (1). To our knowledge, this is the first report of G. bulbilium causing postharvest fruit rot of mangosteen in China. It is uncertain whether the fungus infected mangosteen in Thailand and was carried to China due to commercial relationship. References: (1) C. Constantelos et al. Plant Dis. 95:618, 2011. (2) C. Decock et al. Mycologia 98:488, 2006. (3) L. M. Serrato-Diaz et al. Plant Dis. 96:1225, 2012. (4) A. Sivapalan et al. Australas. Plant Pathol. 27:274, 1998.

scholarly journals First Report of Botrytis cinerea Causing Leaf Spot of Aquilegia vulgaris in Japan

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 425-425 ◽  
Author(s):  
M. Zhang ◽  
T. Tsukiboshi ◽  
I. Okabe
Keyword(s):  
United States ◽  
Botrytis Cinerea ◽  
Leaf Spot ◽  
Leaf Tissue ◽  
The United States ◽  
Plant Diseases ◽  
Its2 Region ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Leaf Spots

European columbine, Aquilegia vulgaris L., Ranunculaceae, is an herbaceous flower widely used in gardens, parterres, and courtyards and is a traditional herbal plant. During the summer of 2008, leaf spots were observed on a plant cultivated along a roadside area in Nasushiobara, Tochigi, Japan. In some courtyards, the leaf spot affected more than 60% of the plants. Early symptoms appeared as small, round or elliptic, brown lesions on the leaves. Lesions expanded to 5 to 15 × 4 to 10 mm, irregular spots that were dark brown to black in the middle, with pale yellow-brown or purple-brown margins. In continuously wet or humid conditions, thick, gray mycelium and conidia appeared on the surface of leaf spots. Conidiophores were melanized at the base and hyaline near the apex, branched, and septated (approximately 3 mm × 16 to 18 μm). Conidia were hyaline, aseptate, ellipsoidal to obovoid, with a slightly protuberant hilum, and ranged from 9 to 14.5 × 5.5 to 6.5 μm. The pathogen was identified as Botrytis cinerea Pers.:Fr on the basis of morphology and sequence of ITS1-5.8s-ITS2 region of rDNA. The sequence (GenBank Accession No. FJ424510) exactly matched the sequences of two Botryotinia fuckeliana (anamorph Botrytis cinerea), (e.g., GenBank Accession Nos. AY686865 and FJ169666) (2). The fungus was isolated on potato dextrose agar (PDA) from a single conidium found on the symptomatic leaf tissue. Colonies of B. cinerea were first hyaline and later turned gray to black when the spores differentiated. Koch's postulates were performed with three whole plants of potted aquilegia. Leaves were inoculated with mycelia plugs harvested from the periphery of a 7-day-old colony; an equal number of plants were inoculated with the plugs of PDA medium only and served as controls. All plants were covered with plastic bags for 24 h to maintain high relative humidity and incubated at 25°C. After 8 days, all mycelium-inoculated plants showed symptoms identical to those observed on leaves from A. vulgaris infected in the field, whereas controls remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was B. cinerea. B. cinerea has been previously reported on A. vulgaris in the United States and China (1,3). To our knowledge, this is the first report of leaf spots caused by B. cinerea on A. vulgaris in Japan. References: (1) Anonymous. Index of Plant Diseases in the United States. USDA Agric. Handb. No 165, 1960. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) Z. Y. Zhang. Flora Fungorum Sinicorum. Vol. 26. Botrytis, Ramularia. Science Press, Beijing, 2006.

scholarly journals First Report of Fruit Rot of Loquat Caused by an Alternaria sp. in Taiwan

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 481-481 ◽  
Author(s):  
Y. Ko ◽  
C. W. Liu ◽  
S. S. Chen ◽  
C. Y. Chen ◽  
K. S. Yao ◽  
...  
Keyword(s):  
Black Spot ◽  
The United States ◽  
Spore Suspension ◽  
Fruit Rot ◽  
Eriobotrya Japonica ◽  
Fluorescent Light ◽  
American Phytopathological Society ◽  
Tropical Fruit ◽  
First Report ◽  
Alternaria Sp

During March 2007, a fruit rot disease was observed in several loquat (Eriobotrya japonica (Thunberg) Lindley) fields located in Taichung, Nantou, and Miaoli counties. Loquat is a valuable fruit crop grown predominantly in central Taiwan, and hence, even a minor yield loss by this new disease is economically significant. Symptoms on fruits initially appeared as small lesions (<1 mm) that later developed into light-to-dark brown, circular, larger (7 mm), sunken lesions, indicating invasion of a pathogen into the fruit. Pieces of rotted fruit tissue (1 × 1 × 1 mm) were immersed for 1 min in 3% commercial bleach, followed by 70% ethanol, cultured on potato dextrose agar (PDA), and incubated under constant fluorescent light (185 ± 35 μE·m–2·s–1) at 24°C for 2 days. Three single conidial isolates (AS1 to AS3) were selected and used in morphological and pathogenicity studies. All three isolates were identified as an Alternaria sp. (1–3) and formed abundant, dark brown mycelium when cultured on PDA with light at 24°C. Conidiophores were 60 to 89 × 3 to 5 μm, densely fasciculate, cylindrical, simple or branched, and had distinct conidial scars. Conidia were 12 to 74 × 6 to 14 μm, golden brown, straight or curved, obclavate with beaks measuring half the length of the conidium, and observed in chains of 10 or more spores with four to seven transverse septa and several longitudinal septa. Pathogenicity tests were conducted twice by inoculating eight surface-sterilized wounded or unwounded fruits with each of the three isolates in each experiment. Two cuts (1 × 1 × 1 mm) were made on each fruit 3 cm apart with a sterile scalpel, and a 300-μl spore suspension (2 × 105 conidia per ml) was placed on each wound. Similarly, a 300-μl spore suspension was placed on unwounded fruits and air dried for 5 min. Control fruits were similarly treated with sterile water. Inoculated fruits were enclosed in a plastic bag and kept at 24 ± 1°C. Symptoms of soft rot were observed on 60% (unwounded) and 100% (wounded) of inoculated fruits 5 days after inoculation, while control fruits did not develop disease symptoms. Reisolation from the symptomatic fruits consistently yielded an Alternaria sp. This fungus previously has been reported as the causal agent of fruit rot or black spot of papaya, mango, kiwifruit, pear, and carambola from Australia, India, Malaysia, South Africa, and the United States (1–3). To our knowledge, this is the first report of fruit rot of loquat caused by an Alternaria sp. in Taiwan. To manage this disease, growers may resort to fungicidal sprays followed by bagging of fruits to reduce pre- and postharvest losses. References: (1) A. L. Jones and H. S. Aldwinckle. Compendium of Apple and Pear Diseases. The American Phytopathological Society. St. Paul, MN, 1990. (2) R. C. Ploetz. Diseases of Tropical Fruit Crops. CABI Publishing. Wallingford, Oxfordshire, UK, 2003. (3) R. C. Ploetz et al. Compendium of Tropical Fruit Diseases. The American Phytopathological Society. St. Paul, MN, 1994.

scholarly journals First Report of Anthracnose Caused by Colletotrichum acutatum on Persimmon Fruit in the United States

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 634-634 ◽  
Author(s):  
S. M. Williamson ◽  
T. B. Sutton
Keyword(s):  
United States ◽  
Filter Paper ◽  
The United States ◽  
Grocery Store ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Diospyros Kaki ◽  
Japanese Persimmon ◽  
First Report ◽  
Persimmon Fruit

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.

scholarly journals First Report of Stigmina palmivora Causing Leaf Spots on Phoenix roebelenii in Brazil

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 849-849 ◽  
Author(s):  
A. Colmán ◽  
R. A. da Silva ◽  
R. Alves ◽  
M. Silva ◽  
R. W. Barreto
Keyword(s):  
Pure Culture ◽  
Leaf Surface ◽  
The United States ◽  
Culture Collection ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Leaf Spots ◽  
Nucleotide Homology ◽  
Query Coverage ◽  
Representative Samples

Phoenix roebelenii (Arecaceae), known as dwarf date (tamareira-anã in Brazil), is a palm native to Southeast Asia and widely cultivated worldwide because of its ornamental value and ease of adaptation to a broad range of climates and soil types (4). In June 2012, some individuals were observed in a private garden in the municipality of Viçosa (state of Minas Gerais, Brazil) bearing numerous necrotic lesions on its leaves. Representative samples were taken, dried in a plant press, and brought to the laboratory for examination. A fungus was regularly associated with the leaf spots. Fungal structures were mounted in lactophenol and slides were examined under a microscope (Olympus BX 51). Spores were taken from sporulating colonies with a sterile fine needle and plated on PDA for isolation. A pure culture was deposited in the culture collection of the Universidade Federal de Viçosa (accession COAD1338). A dried herbarium sample was deposited in the local herbarium (VIC39741). The fungus had the following morphology: conidiophores grouped on sporodochia, cylindrical, 12 to 29 × 5 to 6 μm, dark brown; conidiogenous cells, terminal, proliferating percurrently (annellidic), 8 to 20 × 5 to 6 μm, pale to dark brown; conidia obclavate to subcylindrical, straight, 58 to 147 × 5 to 6 μm, 6 to 16 septate, hila thickened and darkened with a thin-walled projecting papilla, dark brown, and verrucose. The morphology of the Brazilian collections agrees well with the description of Stigmina palmivora (2), a species known to cause leaf spots on P. roebelenii in the United States (Florida) and Japan (3). Pathogenicity was demonstrated through inoculation of leaves of healthy plants by placing 6 mm diameter cuture disks of COAD1338 on the leaf surface followed by incubation in a moist chamber for 48 h and then transferred to a greenhouse bench at 21 ± 3°C. Typical leaf spots were observed 15 days after inoculation. DNA was extracted from the isolate growing in pure culture and ITS and LSU sequences were generated and deposited in GenBank under the accession numbers KF656785 and KF656786, respectively. These were compared by BLASTn with other entries in GenBank, and the closest match for each region were Mycosphaerella colombiensis strain X215 and M. irregulariamosa strain CPC 1362 (EU514231, GU2114441) with 93% of nucleotide homology (over 100% query coverage) for ITS and 98% of nucleotide homology (over 100% query coverage) for LSU. There are no sequences for S. palmivora deposited in public databases for comparison, but for Stigmina platani, the type species in this genus, 86% and 96% nucleotide homology for ITS and LSU with S. palmivora were found. The genus Stigmina is regarded as being polyphyletic (1) and this is probably reflected by these low homology levels found in the BLASTn search. To our knowledge, this is the first report of Stigmina palmivora in Brazil. References: (1) P. W. Crous et al. Stud. Mycol. 75:37, 2012. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, UK, 1971. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 2013. (4) H. Lorenzi et al. Palmeira no Brasil: Exóticas e Nativas, 2nd ed. Editora Plantarum, Nova Odessa, Brazil, 2005.

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