bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Arceuthobium hondurense in Mexico
Authors: Mathiasen R. , Nickrent D. , Parks C. , Beatty J. , Sesnie S. 
Published: May 2007

Honduran dwarf mistletoe (Arceuthobium hondurense Hawksw. & Wiens) is a rare dwarf mistletoe previously known only from Honduras (1,2). In March 2000 we collected a dwarf mistletoe from approximately 7 km west of San Cristobal de las Casas, Chiapas, Mexico near Route 190 (elevation 2,440 m), which was morphologically similar to A. hondurense (1). This population had initially been classified as A. nigrumHawksw. & Wiens (1). However, our morphological measurements and analysis of nuclear rDNA ITS sequences of A. hondurense plants from Honduras (GenBank No. AF325969) and the plants from Chiapas (AF325970) have confirmed that the Chiapan population is A. hondurense and not A. nigrum. An additional population of A. hondurense was discovered in Chiapas approximately 11 km west of Oxchuc near Route 186 (elevation 2160 m). Both of the Chiapan populations of A. hondurense were parasitizing Pinus tecunumanii(Schw.) Eguiluz et Perry. Specimens of A. hondurense from Chiapas were deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. This is the first report of A. hondurense in Mexico and extends its known distribution from northwestern Honduras (3) by approximately 500 km. Although A. hondurense has not been observed in the pine forests of Guatemala, it is probable that it also occurs there (1). References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709. (2) R. Mathiasen et al. Phytologia 36:211, 1998. (3) R. Mathiasen et al. Plant Dis. 84:372, 2000.
First Report of Sclerotinia sclerotiorum on Calendula officinalis in Italy
Authors: Garibaldi A. , Minuto A. , Gullino M. L. 
Published: May 2007

Pot marigold (Calendula officinalis) has recently become popular as a potted ornamental plant in Italy. During the spring 1999, a sudden wilt of 120 day-old plants was observed in the Albenga region of Northern Italy, an area of intensive floriculture production. Initial symptoms included stem necrosis at the soil line and yellowing and tan discoloration of leaves. As stem necrosis progressed, infected plants wilted and died. Necrotic tissues resulted, covered with whitish mycelium that produced dark, spherical (2- to 6-mm diameter) sclerotia. Sclerotinia sclerotiorum was consistently recovered from symptomatic stem sections surface disinfested 1 min in 1% NaOCl and plated on potato dextrose agar (PDA), amended with 100 ppm streptomycin sulfate. Pathogenicity of three isolates was confirmed by inoculating 90-day-old pot marigold plants grown in containers. Inoculum that consisted of wheat kernels infested with mycelium and sclerotia was placed on the soil surface around the base of previously wounded or non-wounded plants. Non-inoculated plants served as controls. All plants were kept outdoors where temperatures ranged between 8 and 16°C, under 50% shade and were maintained moist. Inoculated plants developed symptoms of leaf yellowing, followed by wilt within 7 days, while control plants remained symptomless. Sclerotia developed on infected tissues and S. sclerotiorum was reisolated from inoculated plants. This is the first report of stem blight of C. officinalis caused by S. sclerotiorum in Europe. The disease was previously observed in the United States (1). Reference: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.
First Report of Artichoke Downy Mildew Caused by Bremia lactucae in Argentina
Authors: Carranza M. , Larran S. , Alippi H. 
Published: May 2007

In 1999, downy mildew was detected on artichoke (Cynara scolymus L.) plants from La Plata, Buenos Aires Province. The disease was observed on various commercial varieties. Symptoms were angular interveinal chlorotic spots less than 3 cm in size. These infected areas, although not confluent, covered a wide surface and caused early death of the leaves. On the undersides of these lesions, white-grayish sporulation was abundant, consisting of sporangiophores with dichotomous branches, widened in their peaks with 2 to 7 terminal sterigmata. Sporangia were ellipsoidal, hyaline and 14 to 30 × 12 to 25 μm in size. Oospores were not observed in leaf tissues. The pathogen was identified as Bremia lactucae Regel (1). Pathogenicity was confirmed with the inoculation of healthy artichoke plants. They were incubated in a humidity chamber at 10 to 15°C, and after 16 days chlorotic spots and downy mildew colonies developed. The presence of B. lactucae was confirmed by macro- and microscopic observation and Koch's postulates were fulfilled. This is the first report of downy mildew on artichoke in Argentina. Because it is widespread in the most important artichoke-growing area in Argentina (2), downy mildew should be considered in the cultural and sanitary management of the crop. References: (1) P. Corda. Hypermedia Prot. Plantes, INRA, 1995. (2) A. Ricceti et al. Bol. Hortic. 4:4, 1996.
Epidemic of Potato virus Y and Cucumber mosaic virus in Henan Province Tobacco
Authors: Li X. D. , Li Y. Q. , Wang H. G. 
Published: May 2007

Flue-cured tobacco is an important crop in Henan Province, China. During the 2000 growing season, many tobacco plants showed various degrees of mottling, mosaic, vein clearing, or vein necrosis in most of the counties. Some plants even died at an early stage of growth. A survey was conducted in May-June in several tobacco-growing counties, and the incidence of symptomatic plants in individual fields ranged from 10 to 85%. The most widely planted tobacco varieties, NC89, K326, and K346, were highly susceptible. Symptomatic plants were collected from Jiaxian and Xiangcheng counties and samples were tested by enzyme-linked immunosorbent assay for Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Potato virus Y (PVY), and Potato virus X (PVX). Of 65 samples tested, 21 were positive for only PVY, 16 positive for only CMV, one each was positive for only TMV or PVX. Nineteen samples were doubly infected with various combinations of these viruses and six were infected with combinations of three viruses. The causal agent(s) in the remaining sample could not be determined. In total, CMV was detected in 40 samples, PVY in 38, PVX in 10, and TMV in 7 samples. TMV and CMV used to be the most important viruses and PVY occurred only rarely. But PVY has become prevalent in Henan and in neighboring Shandong province (2). CMV and TMV were reported to be the most prevalent viruses in Shanxi (1) and Fujian Provinces (3). Because resistant varieties are not available, and mixed infections are more common, the results presented here explain why huge damage is occurring in tobacco crops in recent years. Some varieties are partially resistant to TMV and CMV but the varieties commonly grown are highly susceptible to PVY. Therefore, breeding for resistance to viruses, especially to PVY, is urgent to control the occurrence of tobacco viral diseases. References: (1) J. L. Cheng et al. Acta Tabacaria Sin. 4:43, 1998. (2) J. B. Wang et al. Chinese Tobacco Sci. 1:26, 1998. (3) L. H. Xie et al. Acta Tabacaria Sin. 2:25, 1994.
Outbreak of Potato Late Blight and First Report of Mating Type A2 and Metalaxyl Resistance of Phytophthora infestans in Iceland
Authors: Olafsson S. , Hermansen A. 
Published: May 2007

Late blight caused by Phytophthora infestans (Mont.) de Bary was endemic on potato in Iceland from about 1890 until 1961. Probably because of a cooler climate in the 1960s, the disease disappeared and there were no epidemics until 1990 and 1991. Late blight was not found in the period 1992 to 1998 even though the weather conditions were favorable for epidemic development in some of the years. Lack of initial inoculum was probably the limiting factor for an epidemic in Iceland some years. During the summer of 1999, late blight reappeared in Iceland. In August 1999, potato leaves with single lesions of late blight were sampled from two locations and sent to the Norwegian Crop Research Institute. Isolates were trapped by placing infected leaves under tuber slices in petri dishes. Pure cultures were made by picking small pieces of mycelium from the upper side of the potato slice after 7 to 10 days incubation at 15°C and plating them onto modified rye B agar with antibiotics (1). Sixteen isolates maintained on rye B agar were paired with reference isolates of mating types A1and A2 and examined for oospores at the hyphal interfaces between the isolates (1). One isolate was typed as A2 and 15 isolates were A1. Response to metalaxyl was determined for 13 isolates in vitro (1) on rye B agar amended with 5 mg/l metalaxyl-m. One of the A1 isolates was metalaxyl-resistant and 12 isolates, including the A2 isolate, showed intermediate resistance to the fungicide. These data show that the “new” population of P. infestans is now present in Iceland as in the other Nordic countries (1). Iceland imports some seed potatoes each year, mainly from the Netherlands. Imported seed potatoes were probably the source of initial inoculum in 1999 in Iceland. In the future, oospores in the soil might be an additional inoculum source in Iceland since both mating types are now present. Reference: (1) A. Hermansen et al. Plant Pathol. 49:11, 2000.
Stem Canker of Cabbage Seed Stalks Caused by Botrytis cinerea in Western Washington
Authors: Inglis D. , Derie M. , Hsiang T. 
Published: May 2007

Stem cankers were observed during 1998 on bolting stalks of cabbage (Brassica oleracea var. capitata L.) in seed production fields in western Washington. In 1999, approximately 4 ha of cabbage hybrid 'Wk 121, was severely affected. Lesions occurred at the base of seed stalks after they emerged from heads of plants overwintered in the field, or on flower branches and seed-bearing stalks that developed during the growing season. Lesions girdled a branch or stalk, and killed or weakened it so that it broke during pod fill. Isolates of Botrytis cinerea Pers.:Fr. were obtained by plating spores from lesions onto potato dextrose agar. To confirm pathogenicity, stems of 12-day-old seedlings of ‘Wk 121’ were scraped with a razor blade or left intact, atomized with sterile 0.01 % Tween 80 or a suspension of Botrytis cinerea at 1.0 × 106 conidia/ml, and kept at 20°C in a dew chamber in plastic bags. The fungus was reisolated from small lesions on wounded stems inoculated with B. cinerea after 3 days. No lesions developed on non-wounded or wounded control plants. B. cinerea is reported to cause storage rot of cabbage (2) and gray mold on Brassica oleracea L. (cabbage, kale, kohlrabi, wild cabbage) in Washington (1) but not stem canker. This new seed crop disease may be the result of predisposition to infection by freezing injury or mechanical damage on a highly susceptible cultivar grown under cool, wet weather. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society. St. Paul, MN. (2) O. C. Yoder and M. L. Whalen. Can. J. Bot. 53:691, 1975.
Elm Yellows Phytoplasma Lethal to Dutch Elm Disease-Resistant Ulmus americana Cultivars
Authors: Sinclair W. A. , Townsend A. M. , Sherald J. L. 
Published: May 2007

Ulmus americana (American elm) clonal cultivars Independence, New Harmony, and Valley Forge, together with the triploid putative hybrid cultivar Jefferson, were tested for reaction to the elm yellows (EY) phytoplasma. These cultivars all possess resistance to the fungal pathogen Ophiostoma novo-ulmi (1,4) but had not been screened for EY resistance or tolerance. Procedures and conditions of the test were similar to those used previously for assessing EY tolerance of Eurasian elm cultivars (3). In brief, 9 to 15 saplings of each cultivar and of U. americana raised from seed (susceptible controls), growing in a field plot at Ithaca, NY, were challenged by grafting their mainstems with bark patches from U. americana naturally affected by EY. Six to nine additional trees of each clone and of the seedling group were left untreated as controls. Inoculations were performed in July 1999, and trees were evaluated for symptoms in early September 2000. Multiple individuals in every inoculated group developed the syndrome typical of EY in U. americana: epinasty, foliar yellowing, yellow discoloration and necrosis of root and stem phloem, odor of methyl salicylate from moist discolored phloem on first exposure to air, defoliation or sudden permanent wilting, and death (2). The numbers of trees with these symptoms, of those inoculated, were: 9 of 9 Independence, 7 of 11 New Harmony, 10 of 14 Valley Forge, 3 of 13 Jefferson, and 12 of 15 trees grown from seed. Untreated controls remained asymptomatic, except for one tree of Valley Forge and two trees grown from seed that became infected naturally and had symptoms like those in the grafted trees. Based on these results, the elm cultivars named above are typical of U. americana in susceptibility to, and intolerance of, EY phytoplasmal infection. Effective EY resistance or tolerance in this species, although once thought to occur in rare individuals (2), remains undocumented. References: (1) J. L. Sherald et al. Can. J. For. Res. 24:647, 1994. (2) W. A. Sinclair. 2000. Page 121 in: The Elms. C. P. Dunn, ed. Kluwer Academic Publishers, Norwell, MA. (3) W. A. Sinclair et al. Plant Dis. 84:1266–1270, 2000. (4) A. M. Townsend. 2000. Page 271 in: The Elms. C. P. Dunn, ed. Kluwer Academic Publishers, Norwell, MA.
Puccinia sorghi Virulent on Sweet Corn with the Rp1-D Gene in Southern France
Authors: Pataky J. K. , Plaisted D. C. , Scholten D. , de Durand H. F. 
Published: May 2007

The Rp1-D gene, which conveys a chlorotic-fleck resistant reaction to Puccinia sorghi, effectively controlled common rust on sweet corn in North America for nearly 15 years. Biotypes of P. sorghi virulent on plants with the Rp1-D gene were widespread in North America for the first time in 1999 and again in 2000 (1,2). Many Rp-resistant sweet corn hybrids that are developed and grown in North America also are grown in Europe, including France where virulence against the Rp1-D gene has not been reported previously. In September 2000, uredinia of common rust were observed on and collected from sweet corn hybrids with the Rp1-D gene in commercial fields and hybrid trials in the Landes and Pyrénées Atlantiques departments of the Aquitaine region of southwestern France. Severity of rust generally was below 5% on these plants except for a few hybrids for which severity was about 20 to 30%. Common rust was not observed on hybrids with the Rp-G gene. Urediniospores were increased as a bulk population on the susceptible sweet corn hybrid Sterling in a greenhouse. Plants with each of 10 single Rp genes (Rp1-A, Rp1-C, Rp1-D, Rp1-E, Rp1-F, Rp1-I, Rp1-K, Rp1-L, Rp1-N, and Rp-G) or each of six compound rust resistance genes (Rp1-D5, Rp1-JC, Rp1-JFC, Rp-GDJ, Rp-GFJ, and Rp-G5JC) were assayed for reactions to this population of P. sorghi. Two to six different sources of seed of each single Rp gene and two different sources of seed of each compound rust resistance gene were replicates with a single pot of 6 to 18 plants grown from a specific seed source. Plants were inoculated three times on successive days by placing 2 or 3 ml of a urediniospore suspension in the whorl of two- to four-leaved seedlings. Reactions were rated 10 days after the last inoculation. Plants without symptoms or with chlorotic-fleck resistant reactions were inoculated again and rated 10 days later. Uredinia did not form on plants with compound rust resistance genes. Plants with the genes Rp1-E, Rp1-I, Rp1-K, and Rp-G also were resistant although a few, very small uredinia (i.e., type-1 uredinia) were observed on a few plants. Plants with the genes Rp1-A, Rp1-C, Rp1-D, Rp1-F, Rp1-L, and Rp1-N were fully susceptible. This pattern of virulence is the same as that observed during the past two years in North American populations of P. sorghi virulent against Rp1-D. Rp-resistance currently available in most sweet corn hybrids will not be effective in France if these virulent biotypes become prevalent. References: (1) J. K. Pataky et al. Plant Dis. 85:165, 2001. (2) M. C. Pate et al. Plant Dis. 84:1154, 2000.
First Report of Strawberry Fruit Rot Caused by Alternaria tenuissima in Korea
Authors: Lee H. B. , Kim C.-J. , Yu S. H. 
Published: May 2007

A strawberry (Fragaria × ananassa Duch.) fruit rot disease has been observed in several vinyl-house fields at Nonsan and Taejon, Chungnam district, Korea, especially following moist and cool conditions in the spring and again in September. Over the past 7 years, incidence of the disease has ranged from 0.2 to 2.0%. Early symptoms on fruits were characterized by small, irregular lesions, which were slightly sunken and appeared light green to black in color as sporulation began. Conidia were 25 to 55 μm long by 10 to 17 μm wide; beaks, when present, were 2 to 3 μm wide and up to 40 μm long; and conidiophores were 20 to 110 μm long by 3 to 5 μm wide. Older lesions were circular, largely sunken, firm, and dark-green to almost black because of abundant sporulation. The fungus isolated from infected fruit tissues was identified as Alternaria tenuissima (Fries) Wiltshire, based on the morphological characteristics of the conidia and conidiophores. Pathogenicity tests were conducted by inoculating slightly wounded, ripe (red) and immature (green) fruits with a conidial suspension (1 × 106 conidia/ml). Twenty-four ripe and immature fruits were inoculated with each of six isolates in duplicate and placed in a moist chamber for 48 h at 25°C and then transferred to vinyl-house field. After 7 to 10 days fruit rot symptoms were visible on the inoculated fruits and appeared nearly identical to lesions observed in the field, although there were differences in aggressiveness among isolates. Control fruits sprayed with distilled water did not develop any symptoms. Green fruits were generally more resistant to infection than ripe ones. The causal fungus was easily reisolated from lesions on inoculated strawberries. Alternaria fruit rot of strawberries has been reported from the USA, UK, and West Germany (2). Howard and Albregts (1) first reported a strawberry fruit rot caused by A. tenuissima in Florida, but the disease is generally not considered important. However, occasionally losses from this disease have been extensive in Korea. To the authors' knowledge, this is the first report of strawberry fruit rot caused by Alternaria tenuissima in Korea. References: (1) C. M. Howard and E. E. Albregts. Phytopathology 63:638–639, 1973. (2) A. L. Snowdon. Pages 250–252 in: A Color Atlas of Post-Harvest Diseases and Disorders of Fruits and Vegetables. Vol. 1. 1990. Wolfe Scientific, London.
First Report of Sweet potato sunken vein virus Occurring in Lisianthus
Authors: Cohen J. , Lapidot M. , Loebenstein G. , Gera A. 
Published: May 2007

During a survey of Lisianthus (Eustoma grandiflorum) plots in the Northern Negev in Israel, plants infected with Iris yellow spot virus (IYSV) (Genus Tospovirus; 1) were identified. In addition, during electron microscope observations of ultrathin sections through parenchyma phloem cells from some of the IYSV-infected plants, vesicles and virus particles typical of closteroviruses (850 × 12 nm) were observed. As sweet potatoes grown in this area often are infected with Sweet potato sunken vein virus (SPSVV), it was of interest to see if SPSVV also had naturally infected Lisianthus. Using immunosorbent electron microscopy (ISEM) with an antiserum developed against SPSVV (2), trapping and decoration of the suspected chlostero-like particles were observed in some of the field-collected Lisianthus plants. This antiserum did not react with two other closteroviruses, Citrus tristeza virus and Lettuce infectious yellow virus. Inoculation of non-infected Lisianthus plants with SPSVV acquired from sweet potato by whitefly (Bemisia argentifolii), resulted in the presence of vesicles and clostero-like particles in ultrathin sections of parenchyma phloem cells 1 month after inoculation. ISEM tests with SPSVV antiserum were positive. Inoculations of sweet potato from SPSVV-infected Lisianthus plants by whiteflies were not successful. No leaf symptoms of SPSVV were observed in Lisianthus plants, but flower stems were shorter by about one third. These data indicate that Lisianthus is a host for SPSVV. To our knowledge, this is the first report of SPSVV infecting Lisianthus and any species of the Genetianaceae. References: (1) A. Kritzman, H. Beckelman, S. Alexandrov, J. Cohen, J. Lampel, M. Zeidan, B. Raccah and A. Gera. Plant. Dis. 84:1185, 2000. (2) J. Cohen, A. Franck, H. J. Vetten, D. E. Lesemann and G. Loebenstein. Ann. Appl. Biol. 121:257, 1992.
Occurrence of Chilli veinal mottle virus in Solanum aethiopicum in Tanzania
Authors: Nono-Womdim R. , Swai I. S. , Chadha M. L. , Gebre-Selassie K. , Marchoux G. 
Published: May 2007

African eggplant, or garden egg (Solanum aethiopicum) is an important vegetable in most sub-Saharan African countries. Since June 1997, viral symptoms, including mosaic, vein clearing, and stunting, have been observed on several crops of African eggplant cv. Tengeru White at a number of sites in the Arusha region of northern Tanzania. Field inspections revealed disease incidence ranging from 50 to 90%. During the same period, high populations of the green peach aphid Myzus persicae were observed in affected crops of African eggplant. These aphids were also found to reproduce in African eggplants. Flexuous, rodshaped virus-like particles, approximately 750 nm long and 12 nm wide, were found in electron microscope leaf dips from field samples of naturally affected African eggplants. The particle size suggested a species of Potyviridae. Thus, 20 field-infected samples of S. aethiopicum (randomly collected from four farms) were assayed in double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for the presence of Potato virus Y (PVY) and Pepper veinal mottle virus (PVMV), known to infect tomato and other solanaceous crops in the region (2). However, all samples gave negative results. Further DAS-ELISA were performed with the same extracts from naturally infected plants of S. aethiopicum with antisera directed against Tobacco etch virus, Tobacco vein mottling virus, Pepper mottle virus, and Chilli veinal mottle virus (ChiVMV). All 20 samples were positive only for ChiVMV. ChiVMV, a single-stranded RNA virus transmitted in a nonpersistent manner by several aphid species, is one of the most important viruses of pepper in Asia (1). To confirm DAS-ELISA results, an isolate of ChiVMV from African eggplant was transmitted by mechanical inoculations, resulting in disease on tobacco (Nicotiana tobacco cv. Xanthi nc), pepper (Capsicum annuum cv. Yolo Wonder), tomato (Lycopersicon esculentum cv. Tengeru 97), and African eggplant (S. aethiopicum cv. Tengeru White). Extracts from the inoculated plants tested positive for the presence of ChiVMV in DAS-ELISA. This mechanically transmitted isolate did not infect melon (Cucumis melo), cucumber (C. sativus), or cowpea (Vigna unguiculata), which are nonhosts of ChiVMV. To our knowledge, this is the first report of the natural occurrence of ChiVMV in African eggplant. References: (1) S. K. Green et al. PETRIA 9:332, 1999. (2) R. Nono-Womdim et al. J. S. Afr. Soc. Hort. Sci. 6:41–44, 1996.