bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Anthracnose of Velvet Ash Caused by Discula fraxinea in Louisiana
Authors: Holcomb G. E. 
Published: May 2007

Velvet ash (Fraxinus velutina Torr.), a native tree of the southwestern United States, was commonly planted in Louisiana and other southeastern states until horticulturalists lost interest in the plant due to insect and disease problems. For several years, velvet ash trees in Baton Rouge have exhibited necrotic leaf spots and blotches during March and April. Trees frequently have 10 to 25% foliage infection and those most severely infected may show 50% defoliation. Small hyaline conidia that averaged 9.0 × 3.8 μm were produced in acervuli in necrotic tissue on lower leaf surfaces of affected trees. A fungus that produced similar conidia was consistently isolated from infected leaves and grown on potato dextrose agar. Pathogenicity tests were performed by misting 3 × 106 conidia per ml on leaf surfaces of velvet ash seedlings that were then placed in a dew chamber maintained at 26°C for 48 h. Chlorotic leaf spots developed on inoculated plants in 4 to 6 days at 24°C and were followed by necrotic spots and blotches 4 days later. The fungus was reisolated and identified as Discula fraxinea (Peck) Redlin & Stack (previously known as Gloeosporium aridum Ellis & Holw.) (2). Velvet ash anthracnose was first reported from California in 1949 (1), but this is the first report of its occurrence in Louisiana. References: (1) D. M. Coe and W. W. Wagener. Plant Dis. Rep. 33:232, 1949. (2) S. C. Redlin and R. W. Stack. Mycotaxon 32:175, 1988.
First Report of Peanut Stunt Cucumovirus Naturally Infecting Desmodium sp
Authors: Gillaspie A. G. , Ghabrial S. A. 
Published: May 2007

Plant species in the genus Desmodium (Fabaceae) are used as forage and cover crops and include a number of common weeds such as beggarweed (D. tortuosum) and beggarlice (D. intortum). Accessions of the genus are part of the plant genetic resources collection maintained at Griffin, GA. Peanut stunt cucumovirus (PSV) was detected in naturally infected plants of Desmodium sp. PI 322505 (from Brazil) in a germ plasm regeneration plot by a direct antigen coating-enzyme-linked immunosorbent assay (DAC-ELISA) with an antiserum against PSV strain ER (subgroup I) originally isolated from cowpea in Georgia. The infected plants showed mild mosaic symptoms. Indicator host studies in the greenhouse revealed symptoms characteristic of PSV on Nicotiana tabacum cv. Burley 21 (ringspots and oak leaf pattern), Chenopodium album subsp. amaranticolor (chlorotic local lesions), and Vigna unguiculata (chlorotic spots followed by systemic mild mosaic). These symptomatic indicator plants tested positive for PSV by DAC-ELISA. Greenhousegrown plants of D. incanum (kaimi-clover) and D. uncinatum (Spanish tick-clover) were inoculated with the field isolate and the plants were tested for PSV by DAC-ELISA (10 infected of 10 tested and 3 infected of 9 tested, respectively). The PSV isolate infecting Desmodium spp. was found to contain satellite RNA and it generated the predicted products in reverse transcription-polymerase chain reactions (RT-PCRs) with primers based on specific PSV-ER sequences. The RT-PCR products were confirmed by restriction-enzyme digestion (1). This is the first report of PSV naturally infecting a member of the genus Desmodium. Because some members of this genus may grow as perennial weeds near peanut, cowpea, or other host crops, this genus may serve as an alternate/overwintering host for the virus. Reference: (1) R. A. Naidu et al. Phytopathology 85:502, 1995.
First Report of Fire Blight on Indian Hawthorn Cultivar Olivia in Louisiana
Authors: Holcomb G. E. 
Published: May 2007

Twig and branch death were observed on Indian hawthorn (Raphiolepis indica (L.) Lindl.) cv. Olivia in an experimental planting in May 1998. Symptoms resembled those of fire blight caused by Erwinia amylovora and included the release of large numbers of bacteria from stem sections placed in water drops. Small pieces of wood from surface-disinfected cv. Olivia twigs were crushed in drops of sterile water, dilutions made and streaked on yeast extract-dextrose-CaCO3 agar, and single colony cultures established. Pathogenicity tests were performed on immature pear (Pyrus communis L. ‘Kieffer’) and cherry laurel (Prunus caroliniana (Mill.) Aiton) fruits by injecting them with bacterial suspensions containing 105 CFU/ml. Twigs of cv. Olivia were inoculated with a needle that had been dipped in the bacterial cultures. Control inoculations were done with sterile water. Inoculated fruits (nine pear and eight cherry laurel) turned black and oozed bacteria after 5 to 10 days and seven of nine inoculated twigs developed leaf chlorosis followed by browning and death of foliage and twigs after 7 days. Control inoculations were negative. The bacterium was reisolated and identified as E. amylovora based on positive pathogenicity tests and results from Biolog Microplate tests. Although R. umbellata (Thunb.) Makino is a natural host of E. amylovora (1), R. indica was reported only as an experimental host (2) but is now generally recognized as a natural host of E. amylovora. Among nine Indian hawthorn cultivars. (total of 48 plants) in the Louisiana planting, only cv. Olivia was infected with fire blight and all six plants died by late summer. References: (1) E. M. Hildebrand. Phytopathology 44:192, 1954. (2) H. E. Thomas and H. E. Thomas. Phytopathology 21:425, 1931.
Two New Hosts of Xanthomonas campestris pv. vitians
Authors: Sahin F. , Miller S. A. 
Published: May 2007

Bacterial leaf spot of lettuce (Lactuca sativa L.) caused by Xanthomonas campestris pv. vitians (proposed new names X. axonopodis pv. vitians / X. hortorum pv. vitians) is an economically important disease in many areas of the world (1,2). Serious outbreaks occurred in Ohio in 1995 and 1996. The primary sources of the causal agent are presumed to be contaminated seed and infected plant debris in the field. Once the disease is present in a field, crop rotation is required to decrease primary inoculum of the pathogen. Therefore, appropriate crop rotation sequences need to be determined based on the host range of the pathogen. Some vegetable crops, including tomato, pepper, cabbage, collard, kale, radish, and horseradish, were tested for susceptibility to four representative strains of X. campestris pv. vitians by spray inoculation in the greenhouse. Typical symptoms of bacterial leaf spot were observed on tomato and pepper plants 8 days after inoculation, whereas the other crops did not develop diagnostic symptoms. The pathogen was reisolated and Koch's postulates were completed on tomato and pepper. This is the first report that X. campestris pv. vitians strains can cause bacterial spot disease on tomato and pepper. References: (1) C. L. Patterson et al. Plant Dis. 70:982, 1986. (2) L. Vauterin et al. Int. J. Syst. Bacteriol. 45:472, 1995.
Evidence That Xylella fastidiosa Is Associated with Pecan Fungal Leaf Scorch
Authors: Sanderlin R. S. 
Published: May 2007

Several different leaf scorch symptomatologies occur on the foliage of pecan (Carya illinoinensis). The causes of these different scorch symptoms have been associated with environmental stresses, nutritional imbalances, mites, and pathogens. One type of leaf scorch is characterized by necrosis beginning at the tips or margins of the leaflets and progressing toward the midrib and base of the leaflets. The most distinguishing feature of this type of leaf scorch is a dark brown, black, or purplish band of tissue at the interface of the necrotic and green leaflet tissue. This band does not occur on all affected leaflets, but is a consistent feature with this symptomatology. Leaflets with this leaf scorch usually abscise before the entire leaflet becomes necrotic. Affected leaflets will abscise from a compound leaf, while leaflets without symptoms remain on the rachis. When this scorch is severe, the entire leaf including the rachis may abscise. The symptoms are often confined to one area of the tree. Symptoms of this disease appear as early as June but often begin in July. Incidence and severity increase through the remainder of summer and into fall. Over the past 25 years, several different genera of fungi have been reported as being associated with this leaf scorch (2). The phenomenon was named fungal leaf scorch (FLS) because of the association with fungi and the observation that some fungicides reduced the severity of leaf scorch. Genera of fungi implicated in the development of FLS were Pestalotia, Epicoccum, Curvularia, and Fusarium. Recent work has indicated that the disease could be caused by a Phomopsis sp. or Glomerella cingulata or both (1). The symptoms and epidemiology of the FLS are similar to other leaf scorch diseases of hardwood caused by the fastidious xylem-limited bacterium Xylella fastidiosa. A commercial enzyme-linked immunosorbent assay (Agdia, Elkhart, IN) was used to screen for this organism in association with FLS. Assays were conducted by extracting from a composite sample of 9 to 12 sections (approximately 3 cm long) taken from 3 to 4 rachises of each tree tested. Positive reaction for the presence of X. fastidiosa in rachises was recorded from 10 of 10 trees with symptoms of FLS on the Cape Fear cultivar. One of two trees was positive from Cape Fear leaves without symptoms. Symptomless foliage from two less susceptible cultivars, Stuart (two trees) and Sumner (one tree), assayed negative for the bacterium. The association of X. fastidiosa with symptoms of FLS provides evidence that this organism is involved in the etiology of pecan leaf scorch; however, further work is needed to determine the exact etiology. References: (1). A. J. Latham et al. Plant Dis. 79:182, 1995. (2) R. H. Littrell and R. E. Worley. Phytopathology 62:805, 1972.
First Report of Tomato Spotted Wilt Tospovirus Infection of Watermelon in Georgia
Authors: Pappu S. S. , Pappu H. R. , Gitaitis R. D. , Gay J. D. 
Published: May 2007

In 1996, volunteer watermelon plants in a tobacco field in Coffee County, GA, exhibited foliar symptoms that included necrotic ring spots and veinal necrosis. Watermelon plants from experimental plots of the Coastal Plain Experiment Station in Tifton, GA, similarly showed necrotic lesions, often resulting in necrotic ring spots during the late summer of 1997. Out of 16 samples tested for the presence of tomato spotted wilt tospovirus (TSWV) with a commercially available enzyme-linked immunosorbent assay (ELISA) kit (Agdia, Elkhart, IN), six were positive for TSWV. Primers specific to the nucleocapsid gene of TSWV were used in a reverse transcription-polymerase chain reaction assay (RT-PCR) (1) to verify the presence of TSWV. RT-PCR gave an expected PCR product of approximately 350 bp. The amplicon was cloned in pGEM-T vector and the recombinant clone was sequenced. The sequence of the cloned PCR product confirmed the identity of TSWV, thus verifying TSWV infection of watermelon. The potential impact of TSWV on watermelon crop in Georgia will be investigated. This is the first report of natural infection of watermelon by TSWV in Georgia. Reference: (1) H. R. Pappu et al. Tobacco Sci. 40:74, 1996.
Spread of Ergot of Sorghum (Claviceps africana) in Central Mexico
Authors: Velasquez-Valle R. , Narro-Sanchez J. , Mora-Nolasco R. , Odvody G. N. 
Published: May 2007

By late August 1997, sorghum ergot (Claviceps africana Frederickson, Mantle & De Milliano) had not been detected in the Bajio area in central Mexico, the second-largest sorghum (Sorghum bicolor (L.) Moench) producing area in the country, despite earlier 1997 reports of the disease in the adjacent states of San Luis Potosi, Michoacan, and Jalisco. A mid-September survey was conducted in el Bajio, primarily in the state of Guanajuato, and adjacent areas in the states of Michoacan and Jalisco. Infected sorghum heads showing ergot symptoms of honeydew and white secondary sporulation were observed in commercial grain and hybrid seed fields in all three states. Environmental conditions, late summer rains and early low temperatures promoting abundant dew, as well as extended periods of sorghum blooming, contributed to a low and delayed incidence of ergot in Guanajuato. In Michoacan and Jalisco the higher relative humidity and rainfall (around 750 ml) probably contributed to the observed epidemic of ergot. Johnsongrass (Sorghum halepense (L.) Pers.) florets also showed ergot symptoms. Macroconidia in honeydew were hyaline, oblong to oval, slightly constricted at the center, with an average size of 15 × 7 μm, agreeing with the given description of Sphacelia sorghi McRae (2), the anamorph stage of C. africana. No sclerotia were found on any host. Ergot control in this region of Mexico is being attempted by chemical means and burning of heads, even in commercial fields with minimal incidence of ergot. This report of ergot spread complements an earlier note describing the initial detection of the disease in Tamaulipas, the largest sorghum-producing state in Mexico (1). References: (1) J. Aguirre R. et al. Plant Dis. 81:831, 1997. (2) D. E. Frederickson et al. Mycol. Res. 95:1101, 1991.
Leaf Spot of Radicchio Caused by Alternaria cichorii in California
Authors: Koike S. T. , Butler E. E. 
Published: May 2007

A foliar disease of commercially grown radicchio (Cichorium intybus) was observed in 1996 and 1997 in the Salinas Valley (Monterey County), California. Symptoms consisted of circular to oblong, necrotic spots ranging in diameter from 3 to 20 mm and having concentric zones of darker tissue. A fungus identified as Alternaria cichorii Nattrass (1) was observed fruiting on the spots and was consistently isolated from the margins of the spots. Conidia from leaves were obclavate in shape with slender, unbranched beaks extending from the narrow end of the spore body. Spore body dimensions measured 56 to 78 × 14 to 20 μm, and beaks measured 36 to 81 × 1 to 2 μm. Spore bodies had 7 to 9 transverse septa. Often there were no longitudinal septa, but occasionally there were 1 or 2 such septa. For pathogenicity tests, five isolates were grown for 4 weeks on potato dextrose agar under a combination of cool white and Vita-Lite fluorescent tubes on a 12 h light/dark cycle. Conidial suspensions (4.0 × 104 conidia per ml) were sprayed onto 8-week-old radicchio (cv. Rossana Rogers). Plants were incubated in a moist chamber for 48 h and then maintained in a greenhouse. After 12 days, leaf spots similar to the original symptoms developed on all plants inoculated with the five isolates, and the pathogen was reisolated. Control plants sprayed with distilled water remained symptomless. The experiment was repeated and the results were similar. When inoculated onto endive (Cichorium endivia cv. Tres Fine Maraicchere) and two lettuce (Lactuca sativa) cultivars, the isolates caused small (1 to 2 mm in diameter), necrotic, circular leaf spots on endive and Romaine lettuce cv. Green Towers, but did not cause symptoms on the iceberg lettuce cv. Alpha. This is the first report of A. cichorii on commercially grown radicchio in California. In addition, the same disease was confirmed on commercially produced greenhouse transplants of radicchio, indicating that primary inoculum can possibly be seed-borne. Reference: (1) J. C. David. Mycopathologia 129:41, 1995.
First Report of Cucumber Mosaic Cucumovirus on Wasabi in Australia
Authors: Wilson C. R. 
Published: May 2007

Wasabi (Wasabia japonica (Miquel) Matsum.), a native perennial of Japan and Shakhalin Island used to produce a condiment for Japanese dishes, is under commercial development in Tasmania, Australia. Plants propagated within shade houses showed systemic necrotic flecks and veinal necrosis in leaves and sunken necrotic stem lesions similar to those, reported in Japan (1), caused by cucumber mosaic cucumovirus (CMV). Necrosis progressed rapidly, resulting in death of plants transferred to or mechanically inoculated in a glasshouse (15 to 30°C) under full light. Disease progression in plants maintained in shade houses (5 to 20°C) was slower and symptoms less severe. Presence of CMV in symptomatic plants was confirmed by enzyme-linked immunosorbent assay (ELISA), using antiserum from Agdia (Elkhart, IN), and by sap transmission tests to healthy wasabi and Chenopodium quinoa plants. Incidence of CMV among plants in the shade houses was estimated at 10%. A survey of a commercial planting of 400 to 500 plants in November 1997, using ELISA, showed an incidence of 2.6% CMV-infected plants. They were concentrated at the field margins, suggesting that the inoculum originated from external sources rather than from transplants. This pathogen could have significant impact on the longevity and production of this crop in Australia. Reference: (1) S. Adachi. 1987. Wasabi cultivation. Shizuoka Pref. Agric. Exp. Sta. Pub., Shizuoka, Japan.
First Report of Sorghum Ergot Caused by Claviceps africana in the United States
Authors: Isakeit T. , Odvody G. N. , Shelby R. A. 
Published: May 2007

In March 1997, ergot was found on sorghum (Sorghum bicolor (L.) Moench) regrowth in several abandoned commercial grain sorghum fields in Cameron and Hidalgo counties in the Lower Rio Grande Valley (LRGV) of Texas. White sphacelia in florets produced honeydew containing macrospores (hyaline, oblong to oval, 10 to 25 μm × 5 to 7 μm) and microspores (hyaline, spherical, 3 μm in diameter). Macrospores germinated iteratively to form secondary conidia when placed on water agar and in situ following rain. Secondary conidia were hyaline, pyriform, with a protruding hilum, and measured 10 to 17 μm × 5 to 7 μm. High-pressure liquid chromatography analysis detected the alkaloid di-hydroergosine in sphacelia, which is unique to C. africana (1). The pathogen was also confirmed on adjacent johnsongrass (S. halepense). The spread of ergot across Texas was associated with the progressive maturation of the commercial sorghum crop as follows: LRGV (mid-May), Coastal Bend near Corpus Christi (June), Winter Garden area southwest of San Antonio (July), and the seed production region of the Texas Panhandle (mid-August). Ergot incidence ranged from a trace to 10% of the heads in (self-fertile) grain sorghum fields of the LRGV. Most heads had only a few infected florets, but a few heads had 35 to 50% of the florets infected. Only trace amounts were found in grain sorghum fields in other areas of the state. Incidence and severity of ergot were greatest in fields of male-sterile sorghums grown for forage. Ergot was generally low in primary heads of male-sterile sorghums in hybrid seed production fields but, in the absence of pollen, axillary tillers sometimes developed high levels of ergot. The major impact of sorghum ergot is expected to be in hybrid seed production fields in the High Plains of Texas. Reference: (1) D. E. Frederickson et al. Mycol. Res. 95:1101, 1991.
First Report of Celery Mosaic Potyvirus on Dill (Anethum graveolens)
Authors: Bellardi M. G. , Rubies-Autonell C. 
Published: May 2007

In the spring and summer of 1997, nearly 90% of dill plants (Anethum graveolens L.) cultivated in a crop of Emilia-Romagna region (northern Italy), exhibited viruslike symptoms. Approximately 30% of the plants showed narrowing of the leaf lamina and stunting that evolved to yellow or bronze color. The plants appeared bushy and had low seed production. Electron microscopy of leaf-dip preparations revealed the association of flexuous, potyvirus-like particles of 750 nm in length with diseased dill plants. The identity of this virus was established by differential host reactions and serological assays. It was mechanically transmitted only to Chenopodium amaranticolor Coste et Reyn. and C. quinoa Willd. plants (which showed local chloro-necrotic lesions after about a week), and Petunia × hybrida Hort. Vilm.-Andr. plants (latently infected). No infections were obtained in several inoculated Umbelliferae plants, including dill and celery (Apium graveolens L.). Therefore, our isolate is similar to that described by others (1,2) and unlike the type strain that infects only members of the Umbelliferae. Virus particles reacted in protein A sandwich-enzyme-linked immunosorbent assay with antiserum to celery mosaic potyvirus (CeMV) (supplied from the Istituto di Fitovirologia Applicata, CNR, Turin, Italy). This result was further confirmed by immunosorbent electron microscopy decoration tests. CeMV in the field was likely transmitted to dill by abundant aphid populations from weeds and/or other Umbelliferae species cultivated in the same location. In particular, the weed host Daucus carota L. and the cultivated Petroselinum sativum Hoffm. plants both exhibited bronze foliage and stunting, and were found to be infected by CeMV. This note represents the first report of CeMV in A. graveolens. References: (1) E. Luisoni et al. Ann. Phytopathol. 1:375, 1969. (2) C. Rubies-Autonell et al. Phytopathol Mediterr. 35:58, 1996.
First Report of Natural Infection of Pisum sativum subsp. elatius by Mycosphaerella pinodes in Bulgaria
Authors: Kaiser W. J. , Muehlbauer F. J. , Hannan R. M. , Mihov M. 
Published: May 2007

Pisum sativum L. subsp. elatius (Steven ex M. Bieb.) Asch. & Graebn. is a wild pea species that is native to Bulgaria. It readily crosses to the cultivated pea species P. sativum subsp. sativum. Field pea is an important component in the crop rotation system of the northeast region of Bulgaria. Little is known or published on the diseases of wild Pisum subspecies. In June 1997, brown to reddish brown, irregularly shaped lesions 5 to 10 mm in diameter were found on the leaves and stems of P. sativum subsp. elatius growing under native conditions in the low growing vegetation in a mixed forest habitat on the Black Sea coast at Albena, Bulgaria (43°22′26″N; 28°05′02″E) at an elevation of about 50 m. Black pycnidia were observed within lesions and contained hyaline, primarily two-celled conidia that measured 7 to 17 × 3 to 5 μm. On artificially inoculated pea stem pieces incubated on 2% water agar (WA) at 22 to 24°C for 28 days, pseudothecia developed with hyaline, two-celled ascospores constricted at the septum and measuring 12 to 17 × 4 to 7 μm. Black chlamydospores produced singly or in chains also formed in infected foliar tissues and on potato dextrose agar (PDA) and WA. Isolations were made from the lesions on pea tissue onto WA and PDA after disinfesting in 0.25% NaOCl for 5 min. Koch's postulates were fulfilled by inoculating the foliage of P. sativum subsp. sativum cvs. Dark Skin Perfection and Sounder and P. sativum subsp. elatius (W6-20047), and reisolating the fungus from lesions that developed on the inoculated leaves and stems. The wild Pisum fungus was identified as Mycosphaerella pinodes (Berk. & Blox.) Vestergr. based on cultural and morphological characteristics (2), pathogenicity tests, and by comparing random amplified polymorphic DNA (RAPD) markers with those of American Type Culture Collection (ATCC) isolates 201628 to 201633 of M. pinodes. The fungus was identified as a pathogen of cultivated peas in Bulgaria by Kovachevsky and Hristov (1) in 1949. This is the first report of M. pinodes infecting P. sativum subsp. elatius in Bulgaria and other countries where P. sativum subsp. elatius is a native plant species. References: (1) I. H. Kovachevsky and A. Hristov. 1949. Bulgarian Acad. Sci., Scientific-Popular Ser. 10. (2) E. Punithalingam and P. Holliday. 1972. CMI Descript. of Pathog. Fungi and Bacteria, no. 340. Commonwealth Mycol. Institute, Kew, England.