bluuebunny/crossref_metadata_2025 huggingface dataset:
First Report of Hendersonula toruloidea as a Foliar Pathogen of Strawberry-tree (Arbutus unedo) in Europe
Authors: Tsahouridou P. C. , Thanassoulopoulos C. C.
Published: May 2007

During spring 1997 and 1998 in the area of Chalkidiki, in northern Greece, leaves of wild strawberry-tree (Arbutus unedo) were heavily spotted. Small, necrotic brown spots with light gray centers appeared on leaves, and when intense spotting was present, strong defoliation was observed. Isolations from leaves on potato dextrose agar consistently yielded a fungus that was identified as Hendersonula toruloidea (2). Pathogenicity tests on wild strawberry-tree plants were performed, yielding symptoms identical to those originally observed, and H. toruloidea was isolated consistently from inoculated leaves. No cankers appeared on the twigs of the plants, which is a consistent symptom caused by this fungus on strawberry-tree in the United States. Leaf spotting caused by H. toruloidea has been observed in Musa and Rhus spp. (1). This is the first report of H. toruloidea causing leaf spotting and defoliation of strawberry-trees in Europe.

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) R. M. Nattrass. Br. Mycol. Soc. Trans. 18:189, 1945.
First Report of Tobacco streak virus in Strawberry in the Eastern United States
Authors: Hokanson S. C. , Martin R. R. , Maas J. L.
Published: May 2007

In a 1998 virus survey (2) conducted on 23 commercial strawberry (Fragaria × ananassa Duchesne) production farms in the state of Maryland, leaf samples from 1,100 randomly sampled plants were sent to the U.S. Department of Agriculture laboratory in Corvallis, OR, for testing by enzyme-linked immunosorbant assays (ELISA). The viruses identified were Strawberry mild yellow edge, Strawberry crinkle, Strawberry veinbanding, Strawberry mottle, and Tomato ringspot viruses, all of which are known in the eastern United States. Tobacco streak virus (TSV) also was identified in 17 of the samples: 12 originated from a 1-year-old planting of ‘Sweet Charlie’ and 5 from another farm, of which 4 were from a 2-year-old ‘Sweet Charlie’ planting and 1 was from a 2-year-old ‘Delmarvel’ planting. Triple antibody sandwich ELISA was used to detect TSV following the procedures described by Finn and Martin (1), except that leaves from test plants were homogenized (1:20, wt/vol, in blocking buffer) and flat bottom microtiter plates (Nunc, Roskilde, Denmark) and goat anti-mouse (polyvalent) alkaline phosphatase conjugate were used in the assays. The absorbance of each well at 405 nm (A405) was read in an ELISA plate reader. Reactions were considered positive if the A405 values were greater than five times the values of healthy samples. The A405 values of healthy samples ranged from 0.0 to 0.04, with values greater than 0.20 considered positive for TSV. An independent determination of TSV was made in plants shipped from Florida to Maryland in 1999. In this instance, leaf samples from ‘Sweet Charlie’ plants were sent by the Maryland Department of Agriculture to Agdia Inc. (Elkhart, IN), where samples tested positive for TSV.

References: (1) C. E. Finn and R. R. Martin. Plant Dis. 80:769, 1996. (2) S. C. Hokanson, et al. Adv. Strawberry Res. In press.
First Report of Phyllachora ambrosiae in Europe Causing Epidemics on Common Ragweed
Authors: Vajna L. , Bohár G. , Kiss L.
Published: May 2007

Common ragweed (Ambrosia artemisiifolia var. elatior (L.) Descourt.) was introduced to Europe from North America during the nineteenth century. Since the early 1990s, it has become the most widespread and most important allergenic weed in Hungary. In July 1999, during the annual survey of fungal diseases of ragweed in Hungary, plants exhibiting irregular brown spots surrounded by yellowish halos with small black spherical bodies on the upper surface of leaves, especially along the vessels, were collected from three roadside sites. Light microscopy revealed intracellular hyphae in the cells of leaf tissues, including the vessels, and perithecia (186 to 262 μm in diameter) containing paraphyses and asci (93 × 15 μm) with eight hyaline, unicellular ascospores (14 × 7.5 μm). Hyphae also were observed in asymptomatic leaf tissues and the petioles of infected plants. Mature perithecia commonly found in the necrotic spots also were present in asymptomatic, green leaf tissues. Based on the literature (1,2) and on the morphological examination of two herbarium specimens, BPI 636220 and BPI 636225, borrowed from the U.S. National Fungus Collection, the fungus was identified as Phyllachora ambrosiae (Berk. & M.A. Curtis) Sacc., a holobiotrophic pathogen of ragweed in North and South America. This is the first report of P. ambrosiae on ragweed in Europe. To confirm pathogenicity, leaves of five potted ragweed plants, grown from seed in pots, were inoculated with 0.1 ml of an aqueous suspension containing 5 × 105 ascospores per ml. Inoculated plants were placed in a moist chamber for 48 h and kept in the greenhouse at 20 to 25°C. Noninoculated plants served as controls. Two weeks after inoculation, yellowish spots, which later became brown and necrotic, and perithecia appeared on each of the inoculated leaves. Infected leaves died 3 to 4 weeks after inoculation. Symptoms were similar to those seen in the field. The fungus in tissues of inoculated plants was morphologically identical to the original fungus on plants with spontaneous infections. Control plants did not develop symptoms. To determine the distribution of P. ambrosiae in Hungary, a total of 500 ragweed plants were collected at random from 21 locations in all regions of the country between August and October 1999. Symptoms characteristic of P. ambrosiae infections and perithecia of the fungus were found in 92% of all 500 collected plants. From mid-September, all ragweed plants examined had dead leaves and inflorescences. Perithecia of P. ambrosiae were found in leaves, stems, and flowers.

References: (1) P. A. Saccardo. 1883. Sylloge Fungorum. Patavii (Padova), Sumptibus Aucteris. (2) F. Theissen and H. Sydow. 1915. Ann. Mycol. 13:431.
Occurrence of a New Pathotype of Lettuce mosaic virus on Lettuce in Brazil
Authors: Stangarlin O. , Pavan M. A. , da Silva N.
Published: May 2007

Since 1970 lettuce mosaic has not been an important disease of lettuce in Brazil, due to the growing of cultivars that contain gene g, derived from cv. Gallega de Invierno, for tolerance. Recently, however, a widespread, serious outbreak of lettuce mosaic occurred in the State of Sao Paulo. Both lettuce cultivars that lack and those that contain gene g have been affected, suggesting the emergence of a new pathotype of Lettuce mosaic virus (LMV). Commercial lettuce fields were visited, and 20 samples were collected for virus identification by bioassay on differential hosts, serological tests, and electron microscopy. Of these, 12 were infected only by LMV, and 8 contained mixed infections of LMV and a possible new sequivirus, Lettuce mottle virus. Seedlings of susceptible cv. White Boston were inoculated with LMV from tolerant cultivars, and plants were allowed to flower. Seeds were collected and sown, and seedlings with mosaic symptoms were recovered. Twenty monolesional isolates, obtained by passing the virus three times through Chenopodium amaranticolor, were inoculated individually on lettuce differential cvs. Salinas and White Boston (susceptible) and cvs. Salinas 88, Vanguard 75, Ithaca, Malika, and Gallega de Invierno (tolerant) to previously described pathotypes of LMV (1). Considering the susceptibility of all test differentials, we concluded that a LMV pathotype IV exists that has overcome tolerance conferred by genes m and g and is responsible for the new outbreak of LMV in Brazil. This is the first report of LMV-IV in Latin America.

Reference: (1) D. A. C. Pink et al. Plant Pathol. 41:5, 1992.
First Report of Gray Leaf Spot on Perennial Ryegrass in Indiana
Authors: Harmon P. , Rane K. , Ruhl G. , Latin R.
Published: May 2007

Pyricularia grisea, the causal agent of gray leaf spot on turfgrass, was isolated from symptomatic perennial ryegrass (Lolium perenne) leaves collected from a golf course in north-central Indiana in August 1999. Gray leaf spot is an emerging threat to stands of perennial ryegrass in the mid-Atlantic and Midwestern United States (1). Symptoms were first evident in taller (6 cm) mown, rough areas surrounding golf course fairways. Field symptoms included diffuse patches (1 to 4 m in diameter) of thin, yellow-tan turf. Within larger affected areas, some of the turf was dead and matted. Close inspection revealed the presence of typical tan-gray lesions with brown margins and fish hook-like distortion of infected leaf blade tips. Incubation of affected turf in a saturated environment at 23°C for 16 h resulted in production of numerous three-celled, pear-shaped conidia characteristic of those produced by P. grisea. A pure culture of the isolate was grown on V8-juice agar in darkness at 29°C. After 10 days, the culture was exposed to continuous light for 4 days at 23°C to induce sporulation. Conidia were washed from the colony surface with sterile distilled water. Two-week-old perennial ryegrass plants in 8-cm-diameter pots were inoculated with the conidial suspension. Typical gray leaf spot symptoms resulted after incubation of inoculated plants at 27°C for 72 h in a saturated atmosphere. Uninoculated control plants exposed to the same environmental conditions remained healthy. This is the first report of gray leaf spot on perennial ryegrass in Indiana.

Reference: (1) P. J. Landschoot and B. F. Hoyland. Plant Dis. 76:1280, 1992.
First Report ofGloeosporidinasp. Isolated from Lesions on Shoots and Leaves ofEucalyptus nitensandE. globulusin Australia
Authors: Yuan Z. Q. , Wardlaw T. , Mohammed C.
Published: May 2007

A mitosporic fungus with small conidia was frequently isolated from blighted shoots and leaves of young plantation trees and nursery seedlings of Eucalyptus nitens and E. globulus in Tasmania. Lesions on these shoots and leaves are purple to light brown, becoming necrotic with well-defined margins. The fungus is characterized by having acervular conidiomata, cylindrical to lageniform monophialidic conidiogenous cells, and spheroid to pyriform conidia that are hyaline, aseptate, and often produced in chains. The morphological characteristics fit the published description for the genus Gloeosporidina. This is the first record of a member in the genus from Australia and the first time a Gloeosporidina species has been found on eucalypts.
First Report of Armillaria mellea on a Fern from Italy
Authors: Grasso S. , Pane A. , Cacciola S. O.
Published: May 2007

Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped mycelial mats with an odor typical of Armillaria species that were intermixed with the felt-like tangle formed by the rhizomes and roots of the ferns. In autumn, clumps of honey mushrooms with an annulus grew around patches of the withered fern hedge and in other parts of the same garden. The spore print of the basidiocarp was light cream. Basidiospores (8 to 9 × 5 to 6.5 µm) examined under a microscope were hyaline and apiculate. The fungus was isolated in pure culture from infected rhizomes with the selective medium of Kulman and Hendrix (3). In pure culture on 2% malt agar, the fungus formed ribbon-shaped, contorted, fast-growing rhizomorphs that branched profusely. Mycelial proteins of the isolate were analyzed by both polyacrylamide slab gel and starch gel electrophoreses, as described by Bragaloni et al. (1). The electrophoretic patterns of five isozymes (esterase, glutamic oxalacetic transaminase, phospho-glucomutase, alcohol dehydrogenase, and polygalacturonase) of the isolate from fern were identical to those of the reference isolate of A. mellea (Vahl:Fr.) Kumm. from grapevine. Conversely, the patterns were clearly distinct from those of reference isolates from other species, including A. ostoyae (Romagnesi) Herink, A. bulbosa (Barla) Kile et Watling, and A. cepistipes Velenovsky. Thus, on the basis of cultural, morphological, and biochemical characteristics, the species infecting the fern was identified as A. mellea. This pathogen, very common and widespread on wooded or previously wooded sites, has an extremely wide host range, encompassing both woody and herbaceous plants (2,4). However, this is the first report of A. mellea on a fern in Italy.

References: (1) M. Bragaloni and N. Anselmi. Eur. J. For. Pathol. 27:147, 1997. (2) D. F. Farr et al. 1989. Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St. Paul, MN. (3) E. G. Kulman and F. F. Hendrix. Phytopathology 52:1310, 1962. (4) C. G. Shaw and G. A. Kile. 1991 Armillaria root disease. Agric. Handb. No 691. U.S. Department of Agriculture Forest Service, Washington, DC.
Detection of a Whitefly-Transmitted Geminivirus in Launaea spp. in India
Authors: Raj S. K. , Chandra G. , Singh B. P.
Published: May 2007

Launaea acaulis (Roxb.) Babc. Aerr. and L. procumbeus (Roxb.) Ramayya & Rajgopal are weeds that grow near agricultural fields in India during the rainy season. Yellow net symptoms were observed in both species, but not in crops, in 1998 and 1999. Nicotiana tabacum cv. White Burley developed leaf curl symptoms after virus transmission from L. acaulis by whiteflies (Bemisia tabaci). Thus, the involvement of a geminivirus was suspected. Total DNA from infected and uninfected tobacco and Launaea plants was extracted by the cetyl trimethyl ammonium bromide method and precipitated by ethanol. Polymerase chain reaction (PCR), using DNA from infected and uninfected plants as a template and degenerate oli-gonucleotide primers designed from DNA-A of whitefly-transmitted African cassava mosaic virus (ACMV) (1) was performed. An expected ≈500-bp fragment was observed after agarose gel electrophoresis of the PCR product. Total DNA from infected plants gave positive signals and was homologous with the probe from cloned DNA-A of Indian tomato leaf curl virus (2) in high-stringency Southern hybridization tests. No PCR amplification and positive signals were obtained from DNA from uninfected plants. PCR amplification of the 500-bp fragment with primers from DNA-A of whitefly-transmitted ACMV resulted in positive signals, and homology with the probe indicated that L. acaulis and L. procumbens harbor whitefly-transmitted geminivirus infections. This is the first report of geminivirus infection in these Launaea spp. in India.

References: (1) D. Deng et al. Ann. Appl. Biol. 125:327, 1994. (2) K. M. Srivastava, et al. J. Virol. Methods 51:297, 1985.
First Report of Alfalfa mosaic virus in Pachysandra terminalis in Europe
Authors: Cardin L. , Moury B.
Published: May 2007

Pachysandra terminalis (Buxaceae) was introduced from Japan to Europe in 1882. This ornamental plant is grown in northern Europe as a ground cover in shaded sites. Line patterns, more or less necrotic ringspots, and mosaic symptoms on leaves of pachysandra plants have been seen in public gardens in France (Strasbourg, Colmar, Mulhouse, and Nantes) and Germany (Freiburg im Breisgaü). Extracts of plant tissues obtained from these five sites were used for mechanical- and aphid-transmission experiments, enzyme-linked immunosorbent assays (ELISA) with antibodies directed toward a tomato strain of Alfalfa mosaic virus (AMV) (from G. Marchoux, INRA, France), and electron microscopy. All inoculations produced symptoms typical for AMV in Nicotiana tabacum cv. Xanthi-nc tobacco, Chenopodium amaranticolor, C. quinoa, Vigna unguiculata, Phaseolus vulgaris, Vicia faba, Pisum sativum, and Ocimum basilicum (2). Moreover, Medicago arborea, a new host for AMV, showed systemic mosaic on leaflets. On these and the original pachysandras, AMV was readily detected by ELISA. After isolation from three to four local lesions on Vigna unguiculata and further multiplication in tobacco, one isolate was purified. Bacilliform particles of three sizes, typical for AMV, were seen by electron microscopy. Transmissions of the strain to ELISA-negative pachysandras was achieved by mechanical inoculations (7 of 20 inoculated plants were ELISA positive) and by the aphid species Myzus persicae and Aphis craccivora (14 of 17 inoculated plants were infected). Symptoms were observed 2 months after inoculation; some of the plants remained symptomless but were AMV positive in ELISA. As early as 1970, similar symptoms were reported in pachysandra in New Jersey, and AMV was isolated from affected plants (1). However, inoculations of healthy pachysandra plants with AMV was not performed. Our results show the need for an AMV indexing protocol in the propagation of pachysandra to control its spread.

References: (1) D. E. Hershman and E. H. Varney. Plant Dis. 66:1195, 1982. (2) E. M. J. Jaspars and L. Bos. 1980. Alfalfa mosaic virus. No. 229 in: Descriptions of Plant Viruses. Commonw. Mycol. Inst./Assoc. Appl. Biol., Kew, England.
First Report of Alfalfa mosaic, Bean common mosaic, and Broad bean stain viruses in Macrotyloma axillare
Authors: Edeme J. , Hanson J.
Published: May 2007

Chlorotic mottling, mosaic, malformation, and rolling were observed on leaves of the forage legume species Macrotyloma axillare at the International Livestock Research Institute seed multiplication site in Debre Zeit, Ethiopia, in September 1999. M. axillare is a drought-resistant forage legume and a vigorous plant that is palatable to livestock. Disease assessment studies have shown that there can be a 46% reduction in the pod and dry-matter yield of plants infected with Alfalfa mosaic (AMV), Bean common mosaic (BCMV), and Broad bean stain (BBSV) viruses. Diseased leaf tissue (100 g) was tested for AMV, BCMV, and BBSV by antigen-coated plate enzyme-linked immunosorbent assay. Eighteen samples from four diseased plants were replicated six times for each virus. Nicotiana benthamiana was used as a negative control. Visual inspection and data obtained from the enzyme immunosorbent assay (EIA) reader indicated that M. axillare was infected with BCMV, BBSV, and AMV. A pairwise comparison of the mean EIA data for the viruses and against the healthy control also indicated that M. axillare was infected with BCMV, BBSV, and AMV. This is the first report of BCMV, BBSV, and AMV on M. axillare. These viruses are of importance in quarantine because they can reduce pod yield in legumes by 40% (1).

Reference: (1) A. V. Bogdan. 1977. Tropical Pasture and Fodder Plants. Longman Group Limited, New York.
First Report of White Pine Blister Rust in Colorado
Authors: Johnson D. W. , Jacobi W. R.
Published: May 2007

In June 1999, a survey was conducted north and west of Redfeather Lakes, CO (≈64 km northwest of Fort Collins) to determine the extent of white pine blister rust, caused by Cronartium ribicola. To date the disease has not been reported in Colorado on any of the known hosts. The survey was initiated after the disease was reported on limber pine, Pinus flexilis, in 1998. A total of 65 sections were traveled by driving passable roads within three townships in Larimer County in northern Colorado. Infected limber pines were observed in nine sections. Incidence of infected trees ranged from 3 to 50% of trees sampled. A minimum of 10 trees was sampled at each location. Where trees were more abundant, 40 trees were sampled. The highest incidence of blister rust was observed near the Colorado and Wyoming state line along Cherokee Park Road. Both main stem and branch cankers were observed. Cankers appeared to be 3 to 5 years old. Mortality of entire trees was not observed. Ribes spp. were observed in the vicinity of infected limber pines. However, no infection was noted on these alternate rust hosts. Infected trees were observed 18 km south of the Colorado and Wyoming state line. The southward spread of the disease into northern Colorado from infection sites in Wyoming appears to have proceeded slowly since reports of the disease in southern Wyoming during the 1970s (1). Blister rust has the potential to spread throughout the range of white pines in Colorado, which includes scattered populations of both limber and bristlecone pines, P. aristata, located along the Continental Divide from Wyoming to the Colorado and New Mexico state line.

References: (1) D. B. Brown. Plant Dis. Rep. 62:905, 1978.
Effects of Gypsum Soil Amendments on Avocado Growth, Soil Drainage, and Resistance to Phytophthora cinnamomi
Authors: Messenger B. J. , Menge J. A. , Pond E.
Published: May 2007

Infection of avocado seedlings by Phytophthora cinnamomi in infested soil was decreased by 71% by the addition of gypsum soil amendments in replicated greenhouse experiments. Root weights and total seedling weights were not significantly increased by gypsum amendments compared with unamended soil; however, the significant reduction in total seedling weight and root weight caused by P. cinnamomi was largely eliminated by the addition of gypsum. Fresh organic matter amendments alone did not significantly affect the total fresh weight or root weight of avocado seedlings. Root fresh weight was decreased in uninfested soil amended with 5% gypsum and organic matter, but in infested soils, the same treatment increased root fresh weight. Root fresh weight of mature avocado trees in an uninfested grove was not significantly affected by gypsum soil amendments. Avocado seedlings grown in gypsum-amended soil and the roots inoculated with suspensions of Phytophthora cinnamomi zoospores were no more resistant than seedlings grown in unamended soil. Permeability of avocado root membranes, as determined by the amount of 86Rb exuded from root segments over time, was unaffected by growth in gypsum-amended soil. Infiltration of water into soil amended with fine-grade gypsum was impeded initially; whereas soil amended with coarse drywall gypsum drained faster than unamended soil. Drainage was not correlated with root infection of avocados grown in soil infested with P. cinnamomi and amended with gypsum. It appears that large reductions in infection of avocado seedlings by P. cinnamomi in gypsum-amended soil are not caused by an avocado growth response, increased root resistance, or reduced root membrane permeability. Infection is not markedly affected by poor drainage when the soil is amended with high levels of gypsum.
High Frequency of Brown Stem Rot Resistance in Soybean Germ Plasm from Central and Southern China
Authors: Bachman M. S. , Nickell C. D.
Published: May 2007

In an effort to identify new sources of resistance to brown stem rot, caused by Phialophora gregata, 829 soybean accessions originating from 14 provinces in central and southern China and ranging in maturity from group IV to group VIII were obtained from the USDA Soybean Germplasm Collection. All accessions were inoculated in sequential evaluations in the greenhouse with three isolates of P. gregata. Putatively resistant accessions were compared statistically with resistant and susceptible standards. Two hundred forty-one, or approximately 29% of the accessions evaluated, were resistant to all three isolates of P. gregata. The percentage of resistant accessions varied among provinces, with the highest percentages identified in the provinces of Anhui, Gansu, Jiangsu, and Sichuan. Resistance to brown stem rot was not associated with maturity of the accessions or presence of soybean mosaic virus. These resistant accessions could be utilized as sources of brown stem rot resistance through integration of northern and southern soybean germ plasm.
Cross-Compatibility and Distribution of Mating Type Alleles of the Rice Blast Fungus Magnaporthe grisea in India
Authors: Dayakar B. V. , Narayanan N. N. , Gnanamanickam S. S.
Published: May 2007

Two hundred twenty-seven isolates of Magnaporthe grisea isolated from blast-infected rice tissues from different states of India were tested with MAT1-1 and MAT1-2 fertile standard testers to determine their mating type. Of the 227 monoconidial isolates, 90 (39.6%) were fertile and 137 (60.4%) were infertile and did not produce perithecia when mated with any of the four testers. In the states of Meghalaya and Himachal Pradesh, both mating types were found. In the states of Andaman Islands, Andhra Pradesh, Karnataka, Haryana, and Punjab, only mating type MAT1-1 was identified. In states where MAT1-2 occurred, its frequency was low. Among the 90 fertile isolates, 40 (44.4%) produced perithecia, asci, and ascospores, and 11 of those isolates produced perithecia, asci, and ascospores with both MAT1-2 testers, KA-9 of finger millet, and GUY11 of rice origin. However, when monoconidial isolates were mated among themselves, isolates from the same field produced only barren perithecia. Pathogenicity tests of the ascospore progeny derived from crosses of field isolates and host-specific testers revealed that none of the ascospore progeny were as virulent as the parents, despite showing compatible reactions with both rice and finger millet cultivars. These results indicate that recombinant progeny may be at a selective disadvantage despite having an increased host range. This is the first report of the occurrence of high levels of fertility (24 to 52%) in rice isolates of M. grisea in different states of India. In a Southern blot analysis, 58% of 74 isolates were identified as MAT1-1 and 41% as MAT1-2. In this population, 23 Magnaporthe grisea repeat (MGR)-restriction fragment length polymorphism groups or lineages were identified. In terms of lineage composition, the 18 isolates from Meghalaya showed maximal diversity with nine lineages.
First Report of Anthracnose Caused by Glomerella cingulata on Passion Fruit in Argentina
Authors: Wolcan S. , Larran S.
Published: May 2007

Passion fruit (Passiflora edulis Sims.) is a subtropical fruit recently cultivated in Misiones Province, Argentina. In spring 1997, a severe epidemic of anthracnose was observed. Disease incidence was ≍95%, causing high yield losses. Sunken, gray lesions on the whole surface of young fruits were observed. Under humid conditions, acervuli containing masses of spores and dark setae were found within lesions. On leaves, tendrils, and twigs, circular and irregular brown spots with darker edges were observed. Abortion of flowers also was recorded. Cultures on potato dextrose agar yielded abundant, gray aerial mycelium and one-celled, hyaline, oblong conidia with obtuse or rounded ends (11.2 to 15.0 × 3.8 to 4.6 μm). Perithecia were scarce (90.2 to 220.0 μm). Asci were not conspicuous, and ascospores measured 10.8 to 23.4 × 3.5 to 7.0 μm. Based on morphological characteristics, the fungus was identified as Glomerella cingulata (anamorph Colletotrichum gloeosporioides) (2). Fruits and leaves of P. edulis with and without wounds were sprayed with a conidial suspension (106/ml) and incubated in plastic bags for 48 h. Lesions similar to original symptoms were observed after 2 weeks only on wounded leaves and fruits. G. cingulata was reisolated, confirming Koch's postulates. This disease has been recorded in Brazil and Japan (1). This is the first report of G. cingulata on passion fruit in Argentina.

Reference: (1) E. Francisco Neto et al. Summa Phytopathol. 21:25, 1995. (2) J. A. von Arx. Phytopathol. Z. 29:413, 1957.
First Report of a Tobamovirus in Dieffenbachia and Impatiens
Authors: Rivas E. B. , Pezani E. F. , Alexandre M. A. V. , Duarte L. M. L.
Published: May 2007

Tobamoviruses were detected in two ornamental plants, Dieffenbachia picta (Araceae) and Impatiens hawkeri (Balsaminaceae), from different counties in São Paulo State, Brazil. Symptoms were chlorotic spots and rings in D. picta and mosaic, blistering, and leaf deformation in I. hawkeri. Mechanical transmission from both species induced different kinds and intensities of symptoms in the same experimental hosts (Balsaminaceae, Chenopodiaceae, and Solanaceae), except Gomphrena globosa, which was infected only by the isolate from D. picta. The viruses did not infect Cucurbitaceae and Fabaceae. Indirect enzyme-linked immunosorbent assay performed with extracts from infected Nicotiana tabacum ‘White Burley’ and antisera against Cucumber green mottle, mosaic, Frangipani mosaic, Odontoglossum ringspot, Ribgrass mosaic, Tobacco mosaic (TMV), Tomato mosaic, Turnip vein clearing, and Youcai mosaic viruses (genus To-bamovirus) was positive only for TMV. Furthermore, the viruses isolated from D. picta and I. hawkeri cross-reacted with their heterologous antisera. Two sense primers for regions ≍200 and 90 nt upstream of the start codon and an antisense primer ≍60 nt downstream of the terminal codon of the coat protein (CP) gene were designed for two amplification assays. Migrating fragments the same size as the reverse-transcription polymerase chain reaction products from the TMV type strain (479 and 800 bp with internal and external primers, respectively) were produced. The CP gene sequence will allow comparison and identification of the two viruses isolated from D. picta and I. hawkeri.
Implications of Sexual Reproduction for Phytophthora infestans in the United States: Generation of an Aggressive Lineage
Authors: Gavino P. D. , Smart C. D. , Sandrock R. W. , Miller J. S. , Hamm P. B. , Lee T. Yun , Davis R. M. , Fry W. E.
Published: May 2007

Phytophthora infestans isolates (n = 26) collected in the Columbia Basin of Oregon and Washington in 1993, which had been characterized previously for mating type, metalaxyl sensitivity, and alleles at the glucose-6-phosphate isomerase locus, were analyzed for nuclear restriction fragment length polymorphism (RFLP) bands detected by probe RG57 and mitochondrial haplotype. Analyses involving the larger set of markers indicated that this group of isolates satisfied expectations of a sexual progeny: they contained much greater genetic diversity than has been reported for most other epidemic populations of P. infestans in the United States and Canada (16 unique multilocus genotypes); both mating types were present in proximity; all possible combinations of alleles occurred at many pairs of polymorphic loci; and two distinct mitochondrial haplotypes were distributed among the isolates. An in vitro laboratory cross involving the putative parents (US-6 and US-7) as parental strains produced progeny with the same general characteristics as the field isolates. Among the field progeny were two genotypes, US-11 and US-16, that had been described previously but from subsequent and largely clonal collections. Isolates obtained from tomatoes (n = 40) and potatoes (n = 7) in 24 counties in California in 1998 were analyzed as described above, and all except one US-8 isolate from potatoes were of the US-11 clonal lineage, consistent with the hypothesis that the US-11 lineage is an especially fit clonal lineage that has survived over time and can dominate pathogen populations over a large area. We conclude that the 1993 Columbia Basin collection represents a sexual progeny that generated the US-11 lineage, and that this lineage is particularly fit when tomatoes are part of the agroecosystem.
Other Natural Hosts of Potato virus T
Authors: Lizárraga C. , Querci M. , Santa Cruz M. , Bartolini I. , Salazar L. F.
Published: May 2007

Potato virus T (PVT), a member of the genus Trichovirus, was isolated from leaves of naturally infected ulluco (Ullucus tuberosus), oca (Oxalis tuberosa), and mashua (Tropaeolum tuberosum). These Andean tuber crops are often grown in small plots in association with potato (Solanum tuberosum) in the Peruvian highlands. PVT isolates from ulluco, oca, mashua, and potato infected virus-free ulluco, oca, and potato genotypes by mechanical inoculation. The incidence of PVT in mashua, oca, and ulluco accessions from the International Potato Center (CIP) in vitro germplasm bank was less than 10%. A polymerase chain reaction (PCR) product of approximately 330 bp was obtained from each of the four isolates using primers designed from the published PVT sequence. Restriction enzyme digestions of the PCR product did not demonstrate variability.
Determination of Whole-Cell Fatty Acid Profiles for the Characterization and Differentiation of Isolates of Rhizoctonia solani AG-4 And AG-7
Authors: Baird R. E. , Gitaitis R. D. , Carling D. E. , Baird S. M. , Alt P. J. , Mullinix B. G.
Published: May 2007

Fatty acid methyl esters (FAMEs) of isolates of Rhizoctonia solani AG-4 and AG-7 were characterized by gas chromatography and analyzed with Microbial Identification System software. Palmitic, stearic, and oleic acids were common in all isolates from both anastomosis groups (AGs) and accounted for 95% of the C14 to C18 fatty acids present. Oleic acid, most common in both R. solani AG-4 and AG-7 isolates, accounted for the greatest percentages of total FAMEs. The presence, quantities, or absence of individual fatty acids could not be used for distinguishing AG-4 and AG-7 isolates. Anteisopentadecanoic and 9-heptadecanoic acids, however, were specific to all three AG-7 isolates from Japan but absent in other AG-7 isolates and all AG-4 isolates. Pentadecanoic acid occurred in only two of the R. solani AG-4 isolates, but was not found in any of the AG-7 isolates. The AG-4 isolates could be distinguished from AG-7 isolates when quantities of FAMEs and key FAME ratios were analyzed with cluster analysis and principle components were plotted. Isolates of AG-7 from Arkansas, Indiana, and Georgia appeared to be more closely related to each other than to AG-7 isolates from Japan and Mexico. These differences in FAMEs were sufficiently distinct that isolate geographical variability could be determined. A dendrogram analysis cluster constructed from the FAMEs data showed results similar to that of the principal component analysis. Euclidean distances of total AG-4 isolates were distinct from total AG-7 isolates. The Arkansas and Indiana AG-7 isolates had a similar Euclidean distance to each another but the percentages were different for the AG-7 isolates from Japan and Mexico. In conclusion, variability of the FAMEs identified in this study would not be suitable as the main diagnostic tool for distinguishing individual isolates of R. solaniAG-4 from AG-7.
Histopathological Spikelet Changes Produced by Fusarium graminearum in Susceptible and Resistant Wheat Cultivars
Authors: Ribichich Karina F. , Lopez Silvia E. , Vegetti Abelardo C.
Published: May 2007

Scab is an important disease of wheat throughout the world. Fusarium graminearum is the species most frequently isolated in Argentina. Histopathological modifications observed in Pro INTA Oasis (a susceptible Argentine cultivar) and in Sumai 3 (a resistant Chinese cultivar) from the time of inoculation, at the spike emergence stage, until major disease expression (10.5 days postinoculation in the susceptible cultivar) are described. Both cultivars showed a horizontal progression of disease, from anthers to glumes, and a vertical progression, from anthers to rachis. Chlorenchyma was the most damaged tissue, with progressive chlorosis and necrosis. Walls of mesophyll, parenchyma, and epidermal cells around the lesions became thicker, particularly in the resistant cultivar. Vessels and sieve tubes were occluded, particularly the former in the susceptible cultivar and the latter in the resistant cultivar. Possible relationships between tissue changes generated during disease progression and known resistance mechanisms are discussed.
First Report of a Phytoplasma-Associated Leaf Yellowing Syndrome of Palma Jipi Plants in Southern México
Authors: Cordova I. , Oropeza C. , Almeyda H. , Harrison N. A.
Published: May 2007

The palm-like monocot Palma Jipi (Carludovica palmata, Cyclanthaceae), from which Panama hats are traditionally made, is important to the rural economy of southern Mexico and other Latin American countries. A lethal decline of C. palmata plants was first recognized by farmers at Kalkini in the state of Campeche, Mexico, during 1994. Characterized by a progressive yellowing of successively younger leaves, affected plants died within a few weeks after the onset of this primary symptom. Annual losses estimated at 10% of the naturalized C. palmata population have since occurred in the vicinity of Kalkini, an area in which coconut lethal yellowing (LY) disease is also prevalent. The close proximity and superficially similar symptomatology of these two diseases suggested that both might share a common etiology. DNA samples were obtained from five diseased and five healthy C. palmata plants by small scale extraction of immature leaf bases and assessed for phytoplasma DNA by use of the polymerase chain reaction (PCR) at laboratories in Mérida, INIFAP/Universidad Autónoma de Nuevo León (Nuevo León) and the University of Florida (Fort Lauderdale). Samples from symptomatic plants consistently tested positive by PCR employing universal rRNA primers (P1/P7), which amplify a 1.8-kb phytoplasma rDNA product (4), and negative when LY-specific primers LYF1/LYR1 (1) or MMF/MMR (3) were used. No PCR products were evident when DNAs of symptomless plants were evaluated with these primer combinations. Fragment patterns resolved by 8% polyacrylamide gel electrophoresis of rDNA digested separately with either AluI, BamHI, BstUI, DdeI, DraI, EcoRI, HaeIII, HhaI, HinfI, MspI, RsaI, Sau3AI, TaqI, or Tru9I endonucleases revealed no differences between phytoplasma isolates associated with five C. palmata plants. Collectively, restriction fragment length polymorphism (RFLP) patterns generated with key enzymes AluI, BamHI, DraI, and HaeIII clearly differentiated the C. palmata yellows (CPY) phytoplasma from LY and other known phytoplasmas previously characterized by this means (2). A sequence homology of 99.21% between 16S rDNA of CPY (1,537 bp; GenBank accession, AF237615) and LY (1,524 bp; accession, U18747) indicated that these strains were very similar. This relationship was confirmed by phylogenetic analysis of 16S rDNA sequence, which placed both strains into the same phytoplasma subclade.

References: (1) N. A. Harrison et al. Plant Pathol. 43:998, 1994. (2) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (3) J. P. Martínez-Soriano et al. Rev. Mex. Fitopat. 12:75, 1994. (4) C. D. Smart et al. Appl. Environ. Microbiol. 62: 2988, 1996.
First Report of a Leaf Blight and Bulb Decay of Onion by Pantoea ananitas in Colorado
Authors: Schwartz H. F. , Otto K.
Published: May 2007

Sweet Spanish onion (Allium cepa L.) cultivars grown in southern Colorado displayed symptoms of foliar blight and bulb rotting after bulb initiation in early July of 1997, 1998, and 1999. This disease appears identical to that reported from infected onions in Georgia in 1997 (1). Leaf blighting began as whitish to tan lesions, which rapidly coalesced, causing a general wilt, discoloration, and death of affected foliage. A yellow-cream to light orange discoloration progressed into bulbs, resulting in the rotting of neck tissue and between scales. Infection of more than 70% of onion plants exposed to heavy rain and storm damage after bulb initiation occurred in scattered fields in Otero County. Gram negative, rod-shaped, yellow-colored bacteria were consistently recovered from infected foliar and bulb tissues on nutrient agar during this 3-year period. Physiological tests showed that the bacteria utilized glucose in an oxidative and fermentative manner and were catalase positive and oxidase negative. Two strains recovered during 1997 were identified by Microbe Inotech Laboratories (St. Louis, MO) as Pantoea ananas by gas-chromatography fatty acid methyl ester analysis, with similarity indices of 0.70 and 0.79. A literature search determined that the accepted classification is now Pantoea ananatis Serrano (2). To confirm pathogenicity, a 0.5- to 1.0-ml suspension of bacteria (108 CFU/ml sdw) of one of the strains was injected into firm onion bulbs (7.5 to 10.0 cm diameter). After incubation for 14 days at 22°C in enclosed plastic bags in the dark, bulbs were cut in half and scored for visual evidence of yellow to tan discoloration and initial dry rotting prior to reisolation of the pathogen from five of eight inoculated bulbs. No discoloration or disease developed on eight control bulbs injected with water. To our knowledge, this is the first report of P. ananatis from onion grown in Colorado and the western United States.

References: (1) R. D. Gitaitis and J. D. Gay. Plant Dis. 81:1096, 1997. (2) H. G. Truper and L. de Clari. Int. J. System. Bacteriol. 47:908, 1997.
Tomato curly stunt virus, a New Begomovirus of Tomato Within the Tomato yellow leaf curl virus-IS Cluster in South Africa
Authors: Pietersen G. , Idris A. M. , Krüger K. , Brown J. K.
Published: May 2007

Tomato yellow leaf curl virus (TYLCV) causes a serious disease of tomato in many countries throughout the world. Preliminary reports suggested that TYLC disease was present in 1997 in South Africa. In 1998 140 ha of tomato fields in the Onderberg area were assessed for possible presence of TYLCV. Symptoms like those caused by TYLCV isolates in Israel were observed in most fields, and disease incidence ranged from <1 to 50%. Yield losses in individual plants ranged from negligible to 100% and appeared related to the age of the plants at time of infection. Two isolates of the suspect virus were experimentally transmitted from symptomatic tomato to virus-free, glasshouse-grown tomato seedlings by colony. Field and colony whiteflies were identified as the Bemisia tabaci based on mt COI sequence analysis (1). Attempts to transmit the suspect begomovirus by sap inoculation between tomato plants were unsuccessful. Polymerase chain reaction (PCR) amplification with degenerate PCR primers (2) that permit detection of the coat protein gene (AV1) and the common region (CR) of other begomoviruses yielded an amplicon of the expected size (2,100 bp), suggesting begomovirus association with diseased tomato plants. Nucleotide (nt) sequence analysis of AV1 for both tomato isolate AF261885 indicated that they were indistinguishable and shared less than 78% sequence identity with other well-studied begomoviruses, indicating a distinct, previously undescribed begomovirus species. AV1 sequence comparisons also revealed that its closest relatives were members of the TYLCV cluster, which includes South African cassava mosaic virus (77.4%) (AF11785), East African cassava mosaic virus (77.3%) (AJ006459), and TYLCV-IS (76.2%) (X15656). The theoretical Rep binding element in the CR, TCGGT, was identical to TYLCV-IS and Cotton leaf curl virus-Pakistan (AJ002448) (AJ002449). Here, we provisionally designate this new tomato-infecting begomoviral species, Tomato curly stunt virus from South Africa (ToCSV-SA).

References: (1) D. R. Frohlich et al. Mol. Ecol. 8:1683, 1999. (2) A. M. Idris and J. K. Brown. Phytopathology 88:648, 1998.
Severe Yellowing Outbreaks in Tomato in Spain Associated with Infections of Tomato chlorosis virus
Authors: Navas-Castillo J. , Camero R. , Bueno M. , Moriones E.
Published: May 2007

Since 1997, yellowing disease outbreaks have occurred in tomato (Lycopersicon esculentum) crops in southern Spain. The outbreaks were associated with high populations of the whitefly Bemisia tabaci. Symptoms consisted mainly of interveinal yellowing that developed initially on lower leaves and then progressed to the upper part of the plant. Affected plants were less vigorous and yielded less due to reduced fruit growth and delayed ripening. During 1998 and 1999, the yellowing disease was widespread and occurred at high incidences in the Málaga province. The disease agent was readily transmissible from tomato to tomato by B. tabaci biotype Q. Samples from symptomatic tomato plants were analyzed and shown to be infected with Tomato chlorosis virus (ToCV) (genus Crinivirus, family Closteroviridae). This is the first report of ToCV epidemics in Europe.
Stewart's Wilt Reactions of an International Collection of Zea mays Germ Plasm Inoculated with Erwinia stewartii
Authors: Pataky Jerald K. , du Toit Lindsey J. , Freeman Noah D.
Published: May 2007

Maize accessions were evaluated in 1997, 1998, and 1999 to identify additional sources of Stewart's wilt resistance and to determine if reactions differed among accessions collected from various regions of the United States and throughout the world. The distributions of Stewart's wilt reactions rated from 1 (no appreciable spread of symptoms) to 9 (dead plants) were relatively similar among groups of accessions from all regions of the world except for those from the Mid-Atlantic/Ohio River Valley region of the United States, the southern United States, and the northeastern United States. The mean and median Stewart's wilt rating for 1,991 accessions evaluated in 1997 was 4. The mean Stewart's wilt rating for 245 accessions collected from the Mid-Atlantic/Ohio River Valley region was 3.1, which was significantly lower than that for accessions from all other regions. The mean rating for accessions from the southern United States was 3.7, which also was lower than mean ratings for accessions from all other regions. Ratings from trials in 1997 and 1998 were highly correlated (r = 0.87) for 292 accessions and 15 sweet corn hybrid checks evaluated in both years. Of 20 accessions rated below 2 in 1997 and 1998, seven were from Virginia, seven were from the Ohio River Valley or central Corn Belt of the United States, four were from the northern or western Corn Belt of the United States, and two were from Spain. Ratings for these accessions ranged from 1.7 to 3.1 in 1999. Ratings ranged from 2.6 to 3.7 for F1 hybrids of these accessions crossed with one of two susceptible sweet corn inbreds, CrseW30 or Crse16, which were rated 5.7 and 5.4, respectively. Based on the reactions of this collection of germ plasm, it appears that high levels of Stewart's wilt resistance are prevalent only among accessions collected from areas where the disease has been endemic for several years, whereas moderate levels of resistance can be found in accessions collected from nearly everywhere in the world.