bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Disease of Parthenium hysterophorus Incited by an Undescribed Species of Cryptosporiopsis
Authors: Kumar P. Sreerama 
Published: May 2007

Fungal pathogens of parthenium (Parthenium hysterophorus L.), an invasive weed in India, have been under intensive investigation at our Directorate since 1996 for development of mycoherbicides. During the southwest monsoon month of August 1997, a severe foliar disease of the weed was observed near Hunsur (12° 16′N; 76° 18′E; 779.37 masl) in Mysore district of Karnataka State. The primary symptoms consisted of circular to irregular, light brown leaf spots with a diameter up to 8 mm and surrounded by a diffuse chlorotic margin. Isolations on potato dextrose agar (PDA) yielded a relatively fast-growing (approximately 11.4 mm/day) white fungus. The same fungus was isolated consistently from diseased leaves but not from symptomless leaves collected from the vicinity. The mycelium of the fungus on PDA was immersed, branched, septate, and hyaline to pale brown. Conidia (approximately 10.50 × 2.75 µm) were hyaline, thin-walled, smooth, straight, and ellipsoid with obtuse apex and base abruptly tapered to a distinct truncate scar. Pathogenicity was assessed by inoculating healthy, surface-sterilized, mature detached leaves and whole plants (40-day-old) with spore (1 × 106 conidia/ml) or mycelial (0.2 g/ml) suspensions. For both kinds of inoculation, 10 replicates each for detached leaves and whole plants were maintained with equal number of uninoculated controls. Inoculated leaves and plants were incubated at ambient temperature (28 ± 2°C) and 48 h of continuous leaf wetness. Lesions resembling symptoms that occurred in the field were observed on all detached leaves and whole plants within 3 weeks of inoculation. The same fungus was recovered from the diseased tissues excised from all the inoculated material, satisfying Koch's postulates. All the controls remained symptomless and were negative for the fungus. A virulent isolate of this fungus was referred to CABI Bioscience, UK Centre (Egham) and was identified as Cryptosporiopsis sp. (IMI 378270). Although there are at least 12 described species of Cryptosporiopsis Bub. & Kabát (1), no species has been described on parthenium. This pathogen is being studied for its usefulness as a mycoherbicide for parthenium. Reference: (1) B. C. Sutton. 1980. The Coelomycetes. Commonwealth Mycological Institute, Kew, Surrey, England.
First Report of Leaf Rust Caused by Uredo cajani on Pigeonpea in South Africa
Authors: Swart W. J. , Mathews C. , Saxena K. B. 
Published: May 2007

Pigeonpea (Cajanus cajan [L.] Mills.) is an important legume with potential as a dryland crop with multiple uses in the semi-arid areas of South Africa. Approximately 150 tons of dry, split seeds are imported monthly to meet the needs of South Africa. In May 2000, field trials and farmer's plots with plant ages varying from 1 to 3 years old were visited in Mpumalanga and Kwazulu-Natal to assess problems associated with pigeonpea cultivation. Rust was prevalent on more than 80% of plants on young and old leaves at all sites but was most severe at sites in Mpumalanga, where severe rust was observed on all 17 ICRISAT varieties evaluated. Leaf lesions began as chlorotic flecks that expanded and developed into necrotic spots with several orange red to brown uredinia present mostly on the abaxial sides of leaves. Urediospores were 1-celled and initially hyaline, turning dark orange, minutely echinulate, spherical with 2 to 4 circular germpores and measured 20–27 × 17 to 21μ. No telia were found and all morphological characteristics therefore correspond with the CMI description of Uredo cajani Syd. (1). In Africa, pigeonpea rust has been reported from Kenya, Nigeria, Sierra Leone, Tanzania, and Uganda. In South Africa, rust, described as Uromyces dolicholi Arthur (2), has only once been reported on pigeonpea. In the United States, U. dolicholi has also once been reported on pigeonpea (3). However, since U. dolicholi, unlike U. cajani, produces telia and occurs only on Rhyncosia spp. (4), these reports can be considered incorrect. This is therefore the first report of U. cajani on pigeonpea in South Africa. References: (1) K. H. Anahosur and J. M. Waller. 1978. No. 590: Descriptions of Plant Pathogenic Fungi and Bacteria. Commonw. Mycol. Inst., Kew, England. (2) E. M. Doidge. Bothalia 5:1-1094, 1950. (3) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN, 1989. (4) A. Sivanesan. 1970. No. 269: Descriptions of Plant Pathogenic Fungi and Bacteria. Commonw. Mycol. Inst., Kew, England.
Dactuliophora Leaf Spot of Pearl Millet in Niger and Mali
Authors: Wilson J. P. , Hess D. E. , Kumar K. A. 
Published: May 2007

Pearl millet (Pennisetum glaucum (L.) R. Br.) fields and cultivar trials in Sadoré, Niger, and Samanko, Mali, were surveyed in late August 1999 Most plants were in the late stem elongation to panicle exertion stage Local open-pollinated cultivars, experimental hybrids, and inbreds had disease severities of up to 10% of foliage diseased, with most severe disease on lower leaves. Individual, young, brown necrotic lesions averaged 2 × 1 mm and were surrounded by circular to irregular purple watersoaked margins 1 to 7 mm wide. Lesions expanded in irregular concentric rings, with zones of necrosis often separated by zones of green tissue Mature, individual lesions averaged 4.3 × 1.9 cm. Entire leaves could be blighted by coalescing lesions. No sclerotia were observed in young lesions, but sclerotia consistently developed and were macroscopically visible in necrotic tissues of older lesions. Sclerotia were oblong to pyriform (averaging 178 × 124 mm) and borne on erumpent, cup-shaped sclerotiophores. When incubated under high humidity, sterile gray mycelia grew rapidly from necrotic lesions up to a distance of ≈5 mm on the lower leaf surface, which likely resulted in the large concentric zones necrosis. Fungal characteristics and symptoms were consistent with disease caused by Dactuliophora elongata Leakey (1,2). Based on observations at the International Pearl Millet Downy Mildew Virulence Nursery in Mali, it is likely that resistance to D. elongata exists. Leaf spot of pearl millet caused by D. elongata has been reported only in Nigeria (1,2). Our observations confirm that the pathogen also is present on pearl millet Niger and Mali. References: (1) C. L. A. Leakey. Trans. Br. Mycol. Soc. 47:341, 1964. (2) P. D. Tyagi Proc. Ind. Acad. Sci. (Plant Sci.) 94:407, 1985.
First Report of Alternaria Leaf Spot of Spathiphyllum sp. in Argentina
Authors: Cheheid A. L. , Wright E. R. , Lopez S. E. , Rodríguez Codazzi A. M. 
Published: May 2007

Brown necrotic spots surrounded by chlorotic areas have been observed on the leaf margins of Spathiphyllum sp. in many nurseries in and near Buenos Aires, Argentina, since 1997. Spots reached 0.7 × 2 cm and appeared mainly on older leaves of stressed plants. To determine the causal agent of the leaf spot, small pieces of diseased tissue were surface-sterilized for 2 min in 2% sodium hypochlorite and plated on potato dextrose agar. Gray olivaceous to almost black colonies developed in 3 to 4 days. Dark conidiophores, which formed singly or in small groups, were short, less than 100 μm, sometimes flexuous, and occasionally geniculate. The brown to black, obclavate, pyriform, or rostrate conidia were 20 to 25 μm long × 10 to 15 μm wide, with three to four transverse septa and one to three longitudinal or oblique septa. Chains of conidia 5 to 10 spores long were sometimes branched, appearing bushy. The foliage of 15 healthy potted plants previously injured with sterile needles and 15 healthy potted plants without injuries was inoculated with a suspension of 2.8 × 104 conidia per ml. Plants were maintained at 23°C and 100% relative humidity under fluorescent light (12 h light/12 h darkness) for 3 days. Chlorotic and necrotic spots began to develop on the apex and margins of injured and inoculated leaves after 10 days. Lesions tended to coalesce, finally measuring 2.2 × 0.7 cm after 26 days. Control plants, with and without injuries, sprayed with distilled water remained symptomless. Koch's postulates were satisfied after reisolating the fungus. Cultures in potato carrot agar and V8 agar after 7 days exhibited typical characteristics of Alternaria alternata (2–4). An Alternaria sp. has been found previously in the United States on Spathiphyllum sp. (1). This is the first report of Alternaria leaf spot of Spathiphyllum in Argentina. 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) E. G. Simmons. Alternaria themes and variations (226–235): Classification of Citrus pathogens. Mycotaxon 70:263, 1999. (3) E. G. Simmons. Alternaria themes and variations (236–243): Host specific toxin producers. Mycotaxon 70:325, 1999. (4) E. G. Simmons and R. G. Roberts. Alternaria themes and variations (73). Mycotaxon 48:109, 1993.
New Natural Hosts of Tomato spotted wilt virus
Authors: Jordá C. , Font I. , Lázaro A. , Juarez M. , Ortega A. , Lacasa A. 
Published: May 2007

Tomato spotted wilt virus (TSWV) has caused epidemics in recent years in many crops throughout the Mediterranean Region. Tomato, pepper, and lettuce are the crops most affected in Spain. To determine the reservoir hosts for the virus in the area, 210 samples from 95 species of plants were collected and tested for TSWV by double-antibody sandwich enzyme-linked immunosorbent assay with commercial antisera (Loewe Biochemica, Germany: BR-01, serogroup I or TSWV-L). Twenty-one species tested positive, and among them were thirteen newly identified hosts for TSWV (1). Weed species were among the 13 new hosts and included Diplotaxis erucoides (L.) DC., Beta maritima L., Phragmites communis Trin., Malva sylvestris L., Sonchus arvensis L., Sorghum halepense L., Panicum repens L., Atriplex patula L., Coronopus squamatus (Forssk.) Ascherson, Cuscuta sp., Xanthium spinosum L., Suaeda vera J.F., and Ecballium elaterium (L.) A. Rich. Most of these plants were asymptomatic hosts, but the Sonchus sp. showed typical symptoms of TSWV, such as yellows, bronzing, ring spots, necrosis, curling of young leaves, and growth reduction. D. erucoides, B. maritima, M. sylvestris, X. spinosum, and E. elaterium showed chlorosis and growth reduction. Reference: (1) C. Jorda et al. 1998. Anexo no. 3. Pages 381–386 in: The Health of Tomato Crops. Phytoma-España S. L., Valencia, Spain.
Occurrence and Virulence of Bipolaris hawaiiensis on Bermudagrass (Cynodon dactylon) on Poultry Waste Application Sites in Mississippi
Authors: Pratt R. G. 
Published: May 2007

Bipolaris hawaiiensis has been reported on bermudagrass (Cynodon dactylon) and other Cynodon spp. from subtropical areas around the world (2). This pathogen has not previously been reported on bermudagrass in North America (1) nor has its virulence been compared with that of other Bipolaris spp. on this host. In July and October 1999, frequencies of dematiaceous hyphomycetous pathogens in live but symptomatic leaves of bermudagrass were determined on two poultry waste application sites in Smith and Covington counties, MS, where foliar disease symptoms were widespread. Common bermudagrass was being grazed in Covington County, and cv. Alicia was being grown for hay in Smith County. At each date and site, 100 stems with leaves exhibiting symptoms of chlorosis and necrosis were collected, and a single leaf with well-developed symptoms from each stem was assayed for pathogens by surface-disinfesting, plating on water agar, and observing fungal sporulation. Multiple species of pathogens were detected on most leaves. Identities and mean frequencies of observed pathogen species across both sites and sampling dates were Exserohilum rostratum (62%), Bipolaris cynodontis (98%), Curvularia lunata (28%), C. geniculata (20%), B. spicifera (3%), and B. hawaiiensis (3%). B. hawaiiensis was detected at both sites and on both sampling dates. It was distinguished from B. cynodontis by smaller conidia (14 to 28 μm long) and from B. spicifera by more than three pseudosepta per conidium. Virulence of B. hawaiiensis on bermudagrass, compared with B. cynodontis and B. spicifera, was assessed in two identical inoculation experiments using three pathogen-inoculated treatments plus an uninoculated control. In each experiment, foliage of 12-week-old plants in five replicate pots per treatment was sprayed with 4 × 104 conidia per ml of water of each pathogen. The pots were incubated under 12-h plant-growth lights at 25°C for 3 days in a water-saturated atmosphere to initiate infection and then grown for seven additional days in ambient air under plant-growth lights at 25°C. All three pathogens induced symptoms of chlorosis and necrotic lesions. Symptoms induced by B. hawaiiensis were similar in severity to those produced by B. spicifera and less severe than those produced by B. cynodontis. To our knowledge, this is the first report of B. hawaiiensis on bermudagrass in North America. The site in Smith County also apparently represents its northernmost known point of occurrence on this continent (2). References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (2) A. Sivanesan. Graminicolous Species of Bipolaris, Curvularia, Drechslera, Exserohilum and their Teleomorphs. Mycol. Pap. No. 158, CAB International Mycological Institute, Wallingford, U.K., 1987.
Identification of an Isolate of Potato virus Y-Tuber Necrotic Strain on Clary Sage (Salvia sclarea)
Authors: Bellardi M. G. , Rubies-Autonell C. , Cerato C. 
Published: May 2007

In 1999, clary sage plants (Salvia sclarea L.) at the Herb Garden of Casola Valsenio (Emilia-Romagna Region, northern Italy) exhibited malformed leaves with yellow spots and line patterns. Sap from leaves of symptomatic sage plants caused symptoms in inoculated Chenopodium amaranticolor Coste et Reyn. plants (local chloro-necrotic lesions developed 7 to 10 days after inoculation) and Nicotiana tabacum L. ‘White Burley’ and ‘Samsun’ plants (systemic veinal necrosis developed ≈ 2 weeks after inoculation). Leaves from symptomatic sage plants tested positive for Potato virus Y (PVY) based on immunoelectron microscopy, gold-labeled decoration, and protein A sandwich enzyme-linked immunosorbent assay (ELISA), using antiserum to PVY (PVAS 50a, American Type Culture Collection, Manassas, VA). Double-antibody sandwich-ELISA, using specific monoclonal antibodies (BioReba AG, Reinach, Switzerland) to the tobacco veinal necrosis strain group of PVY (PVY-N), revealed that the PVY isolate from sage belonged to this group. Immunocapture-reverse transcription-polymerase chain reaction, using specific primers for PVY and the tuber necrotic strain of PVY (PVY-NTN), further classified the sage isolate as PVY-NTN (1). PVY-NTN causes serious damage to potato in Europe. Clary sage, one of the most important aromatic plants cultivated worldwide as a source of essential oils, represents a new natural host of PVY-NTN. Reference: (1) H. L. Weidemann and E. Maiss. J. Plant Dis. Prot. 103:337, 1996.
Cryptodiaporthe Canker of Pagoda Dogwood in North Dakota
Authors: Redlin S. C. , Stack R. W. 
Published: May 2007

Cryptodiaporthe canker, caused by Cryptodiaporthe corni (Wehm.) Petrak (anamorph Myxosporium nitidum Berk. & Curt.), is known to occur only on pagoda dogwood (Cornus alternifolia L. fil.) throughout its native range in eastern Canada and most of the eastern United States (1). Cankered branches with yellow-to-orange pigmented bark were recently observed on four ≈25-year-old C. alternifolia plants in an ornamental planting on the campus of North Dakota State University in Fargo. Although the fungal anamorph was usually present on all symptomatic materials, the teleomorph was also present on branches with larger diameters (>15 mm). Collections of infected branches made on 25 April 2001 contained perithecia but did not contain mature ascospores. Shoot growth began during the first week of May. Subsequent collections made on 11 May and 8 June 2001 contained perithecia with mature ascospores. A previous collection made on 12 October 2000 contained fully developed perithecia devoid of ascospores. A range of symptoms was present among the individual trees: one tree was severely cankered (up to 4 cm diameter) with many dead branches; one tree showed only minor damage with tip dieback on a few small twigs; and two trees had intermediate symptoms (1 cm diameter with cankers) with several dead branches. Pagoda dogwood is generally seed propagated, and differences in disease severity observed in these plants may be the result of genetic variation in resistance. Selection for resistant genotypes may be a possibility. Specimens (BPI 840955A and B) consisting of cankered branches containing both fungal morphs were deposited at the U.S. National Fungus Collections at Beltsville, MD. Although Cryptodiaporthe canker was previously collected from a native woodland tree in Minnesota (1), the current North Dakota specimens were collected from cultivated plants in a landscape setting. To our knowledge, this is the first report of Cryptodiaporthe canker in North Dakota. Management of this disease may need to be considered when recommending C. alternifolia for horticultural plantings. Reference: (1) S. C. Redlin and A. Y. Rossman. Mycologia 83:200, 1991.
First Report of Pepino mosaic virus on Natural Hosts
Authors: Jordá C. , Pérez A. Lázaro , Martínez Culebras P. V. , Lacasa A. 
Published: May 2007

Pepino mosaic virus (PepMV) is a potexvirus recently identified as the causal agent of a new disease occurring in protected tomato (Lycopersicon esculentum Mill.) crops in the Netherlands (2). PepMV has been subsequently identified in England, Germany, Italy, Morocco, Portugal, and Spain. The new disease has become a serious problem for tomato production in Europe. Most infected tomato plants expressed leaf distortion, chlorosis, and yellow mosaic. Other plants expressed mosaic and bubbling of the leaf surface. Tomato fruits showing severe discoloration and mosaic were observed in protected tomato crops. Symptoms attenuated in tomato plants as the ambient temperature increased. At present, only Solanum muricatum Ait. (Peruvian pepino) and L. esculentum are affected by PepMV.To determine possible reservoir hosts for this virus, 70 samples from Amaranthus sp., A. viridis (L.) Britton et al., Chenopodium murale L., Convolvulus arvensis L., Malva parviflora L., Nicotiana glauca Grah., Polypogon monspeliensis (L.) Desf., Senecio vulgaris L., Sisybrium sp., Solanum nigrum L., and Sonchus oleraceus L. were analyzed. The plants were collected around greenhouses affected by PepMV from different regions in Spain (Murcia and Canary Islands). The samples were analyzed for PepMV by double-antibody sandwich enzyme-linked immunosorbent assay with a commercial antiserum (DSMZ AS-0554, Biologische Bundesantstal, Braunschweig, Germany). Only Amaranthus sp., M. parviflora, N. glauca, Solanum nigrum, and Sonchus oleraceus tested postive. The presence of PepMV in these weed species was confirmed by electron microscopy and reverse transcription-polymerase chain reaction using degenerate primers for potexvirus (1). All the hosts analyzed were asymptomatic. However, symptoms were reproduced by mechanically inoculating tomato plants with sap from naturally infected weeds. To our knowledge, this is the first report of natural infection of weeds by PepMV. References: (1) A. Gibbs et al. J. Virol. Methods 74:67, 1998. (2) R. A. A. Van der Vlugt et al. Plant Dis. 84:103, 2000.
Alternaria alternata Causing Flower Stem Blight of Lupinus havardii
Authors: Colbaugh P. F. , Mackay W. A. , Davis T. D. 
Published: May 2007

Lupinus havardii Wats., commonly known as Big Bend or Chisos bluebonnet, is a showy winter annual that can reach 1.0 to 1.5 m in height and produces blue, fragrant inflorescence (racemes). L. havardii is native to a narrow geographic range along the Mexican border in southwest Texas. The inflorescence of L. havardii has considerable potential in the cut flower industry where there is a need for high-quality, durable flowers with a blue color (1). Several crops have been produced in the greenhouse to determine production and post-harvest characteristics of the cut inflorescence. Under greenhouse growing conditions during March through June 1999, numerous plants of L. havardii cv. Texas Sapphire grown in raised beds and in containers in both Dallas and El Paso, TX, were observed with blighted flower racemes with light brown to gray lesions ranging from 1 to 5 cm in length. The racemes were attacked at varying ages and eventually assumed a hooked appearance where the terminal 15 cm of the raceme was bent downward. Isolations from symptomatic lesions removed from L. havardii flower stalks consistently yielded cultures of an Alternaria sp. on potato-dextrose agar. Typical conidia measured 27 μm length and 11 μm width with 3 to 5 transverse septa. The fungus was identified as A. alternata (Fries) Keissler consistent with the description in Ellis (2). Pathogenicity tests were conducted in the laboratory by inoculating cut inflorescences with agar disks containing the fungus. Inoculations produced light brown lesions on the racemes that were typical of disease symptoms observed on greenhouse crops. In addition to the blue-flowered Texas Sapphire cultivar, we also observed the disease symptoms on pink and white flowered breeding lines of L. havardii. This disease is important as a flower stem blighting pathogen and could severely restrict production of cut flowers during the growing season. This is the first report of Alternaria sp. attacking L. havardii. References: (1) T. D. Davis. HortScience 29:1110, 1994. (2) M. B. Ellis. 1971. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute Kew, England.