RESUMEN

OBJECTIVES: We used data from the TalaSurvey study to examine associations between dental health experiences, social network characteristics, and levels of behavioral and psychological acculturation in one location in the American Midwest. METHODS: Starting in parishes and community organizations, we identified adults of Mexican origin living in Indianapolis, who were 1st- or 2nd-generation immigrants from Tala, Mexico. Using a social networks methodology and following extensive formative research, we created an egocentric social network survey and administered it via face-to-face interviews. We identified the peers (alters) in interviewees' (egos) personal networks. We asked egos about multiple oral health and dental care variables for self and for alters. Acculturation (psychological and behavioral) was measured with a validated tool. Through logistic and negative binomial regression, we examined the effects of acculturation and network composition on ego's dental insurance status, dental office visits, and the reason for most recent dental office visit. RESULTS: A total of 332 egos (mean age 36; 63% female) were interviewed: 90% were born in Mexico; 45% had completed elementary school or lower; and most had low income. Each ego named 3.9 (SD±1.9) alters in his/her personal network, for a total of 1299 alters (mean age 39; 61% female). Both behavioral acculturation and psychological acculturation were moderately associated with dental insurance coverage, and greater behavioral acculturation predicted more frequent dental care. More psychologically acculturated egos were more likely to seek preventive care. Further, egos with more highly educated networks sought care more frequently and for preventive purposes, net of ego's own education and acculturation. CONCLUSIONS: This study contextualizes acculturation of Mexican Americans within the personal networks in which oral health discussion takes place. The findings underscore the critical importance of acculturation and social network factors in shaping a subgroup of Latinos' orientation toward dental care.

Asunto(s)

Aculturación , Atención Odontológica/estadística & datos numéricos , Americanos Mexicanos/psicología , Apoyo Social , Adulto , Femenino , Humanos , Entrevistas como Asunto , Masculino , Odontología Preventiva , Estados Unidos

RESUMEN

OBJECTIVES: We describe neuropsychological test performance (NP) in antiretroviral treatment (ART)-naïve HIV-positive individuals with CD4 cell counts above 500 cells/µL. METHODS: In a neurology substudy of the International Network for Strategic Initiatives in Global HIV Trials (INSIGHT) Strategic Timing of AntiRetroviral Treatment (START) study, eight neurocognitive tests were administered. The primary measure of NP was the quantitative NP z-score (QNPZ-8), the average of the z-scores for the eight tests. Associations of baseline factors with QNPZ-8 scores were assessed by multiple regression. Mild neurocognitive impairment (NCI) was defined as z-scores < -1 in at least two of six cognitive domains. RESULTS: A total of 608 participants had a median age of 34 years; 11% were women and 15% were black; the median time since HIV diagnosis was 0.9 years; the median CD4 cell count was 633 cells/µL; 19.9% had mild NCI. Better NP was independently associated with younger age, being white, higher body mass index (0.10 per 10 kg/m(2) higher), and higher haematocrit percentage (0.19 per 10% higher). Worse NP was associated with longer time since HIV diagnosis (-0.17 per 10 years), diabetes (-0.29) and higher Framingham risk score (-0.15 per 10 points higher). QNPZ-8 scores differed significantly between geographical locations, with the lowest scores in Brazil and Argentina/Chile. CONCLUSIONS: This is the largest study of NP in ART-naïve HIV-positive adults with CD4 counts > 500 cells/µL. Demographic factors and diabetes were most strongly associated with NP. Unmeasured educational/sociocultural factors may explain geographical differences. Poorer NP was independently associated with longer time since HIV diagnosis, suggesting that untreated HIV infection might deleteriously affect NP, but the effect was small.

Asunto(s)

Trastornos del Conocimiento/epidemiología , Infecciones por VIH/complicaciones , Adolescente , Adulto , Argentina , Brasil , Recuento de Linfocito CD4 , Chile , Femenino , Infecciones por VIH/inmunología , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Prevalencia , Adulto Joven

RESUMEN

In February 2009, irregular-shaped leaf spots affected blueberry (Vaccinium corymbosum L. 'Blue Crisp', 'Misty', and 'Sharp Blue') nursery plants in Buenos Aires. Single-spore cultures on potato dextrose agar and oat agar showed aerial white mycelium that turned light and dark gray, dark brown acervuli with setae, and a salmon-to-orange conidial mass. Septate, dark brown, 62 to 78 µm long setae were abundant in the acervulus. Conidia were unicellular, hyaline, straight, cylindrical, round at the ends, and averaged 15.2 (12.1 to 16.9) × 5.4 (4.9 to 6.2) µm. Dark brown, ovate to clavate, 10.25 × 6.25 µm (9 to 12 × 5 to 8) appressoria with a noticeable pore formed on slides near the edge of the cover glass. Dark subglobose structures were recorded immersed in the culture medium. No asci or ascospores were observed, indicating a nonhomothallic condition. The fungus was identified as Colletotrichum gloeosporioides (Penz.) Penz & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) with traits similar to those already described (1). DNA was obtained from mycelium with a standard DNA extraction kit and the ribosomal, internal transcribed spacer (ITS) 1 and ITS2 regions were PCR amplified and sequenced with primers ITS1 and ITS4 (2). A BLASTN algorithm search revealed 100% identity of the sequence (535 bp long) with G. cingulata/C. gloeosporioides from citrus and mango and one from coffee identified as C. kahawae (GenBank Accession No. JF908919). The nucleotide sequence was deposited in GenBank (Accession No. JQ340087). Pathogenicity was verified on young plants and detached leaves of highbush blueberry 'Emerald', 'Misty', 'O'Neal', and 'Santa Fe', olive (Olea europaea 'Arbequina'), and marketed fruits of apple, mango, orange, and tomato. Disinfected healthy leaves were inoculated with a 9-mm2 mycelial block and incubated at 24°C with 12 h of light. Young plants were infected by placing the disinfected end of the branches within a micropipette tip filled with mycelium and kept under greenhouse conditions. Asymptomatic fruits of apple, mango, orange, and tomato were inoculated by placing a mycelial block on a small wound made on their surface. Detached leaves of highbush blueberry 'Emerald', 'O'Neal', 'Misty', and 'Santa Fe' showed 0.1 to 1.5 × 0.8 to 2 cm necrotic lesions after 3 days, covering 43 to 100% of the 'Emerald' leaf area after 8 days. Young plants of blueberry 'Emerald' and 'Misty' showed 1.5 to 3 cm necrotic lesions, acervuli, a salmon-orange conidial mass, and death of leaves at 25 days. On olive 'Arbequina', leaf necrotic lesions reached 0.1 to 3.5 cm after 5 days. Symptoms developed slowly on infected tomato fruits while inoculated fruits of apple, mango, and orange showed dark brown lesions that measured 2 to 7 × 1 to 3.5 cm at 5 days. No symptoms were observed on controls. The fungus was reisolated from inoculated plant parts. The disease was previously cited in Argentina (3), but to our knowledge, this is the first report of a nonhomothallic strain of G. cingulata from highbush blueberry colonizing and deteriorating fruits of apple, mango, orange, and tomato. References: (1) J. M. E. Mourde. No 315. CMI Descriptions of Pathogenic Fungi and Bacteria. Kew, Surrey, UK, 1971. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (3) E.R. Wright et al. OEPP/EPPO Bull. 28:219, 1998.

RESUMEN

Many low-income countries face enormous constraints which limit the development of mental health services. The World Health Organization (WHO) made ten recommendations to facilitate the development of mental health services; among these is the integration of mental health into primary care. Jamaica developed an integrated collaborative system of mental health care through the adoption of a primary care model which is central to the delivery of mental health care. This model emphasized the integration of mental health into primary care and, in expanding the role of the mental health team, made it more collaborative. Mental health services were mainstreamed into primary care and several strategies facilitated this process. These included the training of staff in primary care, the availability of psychotropic medication in primary care facilities and the provision of mental health beds at the community level. Furthermore, focus was placed on human development and the involvement of consumers in the policy development and service delivery. This has resulted in a reduction in the population of the mental health hospital and expansion in the community mental health services.

Asunto(s)

Servicios de Salud Mental/organización & administración , Modelos Organizacionales , Atención Primaria de Salud/organización & administración , Servicios Comunitarios de Salud Mental/organización & administración , Conducta Cooperativa , Humanos , Jamaica

RESUMEN

In 2009, a highbush blueberry (Vaccinium corymbosum L. 'O'Neal') field located in Rojas, Buenos Aires Province showed 30% of plants with dry or dead branches. Disinfected root pieces were placed on water agar and incubated at 24°C. A fungal colony was obtained and purified by successive transfers of an individual hyphal tip from a sparsely growing colony. Colony color and growth rate were evaluated in potato dextrose agar where the fungus produced white-to-pale pink colonies and grew 3.5 cm after 5 days. The fungus was studied on Spezieller Nährstoffarmer agar (2), carnation leaf-piece agar, and KCl agar where it produced abundant single-celled hyaline microconidia in moderate-length chains and in false heads originated from monophialides and polyphialides. Microconidia measured 6 to 12 × 2 to 3 µm (average 8 × 2.3 µm). On KCl, chains of microconidia and tan-to-light cream sporodochia with 3- to 5-septate, slender, relatively straight macroconidia were easily observed after 4 and 10 days, respectively. Macroconidia measured 38 to 48 × 3.5 to 4 µm (average 43.9 × 3.9 µm). Chlamydospores and sclerotia were not present. Data coincided with the description for Fusarium proliferatum (Matsush.) Niremberg ex Gerlach & Niremberg. The isolate was deposited in the IMYZA Microbial Collection as INTA-IMC 144. The fungus was cultured in 100 ml of Czapek-Dox supplemented with sucrose, peptone, yeast extract, sodium nitrate, and vitamins for 4 days. Genomic DNA was obtained with a DNA extraction kit, PCR amplified with primers ITS1 and ITS4 for the internal transcribed spacer (ITS) region of ribosomal genes, and sequenced. The nucleotide sequence (Accession No JF913468) was compared with GenBank records. The sequence shared 99% identity with Accession No HQ113948 for F. proliferatum. Pathogenicity was confirmed in 1-year-old 'O'Neal' plants. A 10-ml suspension (2.4 × 106 conidia/ml in sterile distilled water) was applied to six potted plants grown in sterilized potting mix. Roots were superficially wounded with a needle. Control plants were treated with sterile distilled water. Plants were incubated at 24°C and a 12-h photoperiod. After 90 days, plants showed root rot, leaf chlorosis, and branch necrosis followed by plant death. Control plants remained healthy. F. proliferatum was reisolated from diseased roots of inoculated plants. This fungus was previously cited in Argentina on asparagus (1), corn (1,3), and oat (4). To our knowledge, this is the first report of F. proliferatum as a root pathogen of highbush blueberry in Argentina. References: (1) G. Lori et al. Plant Dis. 82:1405, 1998. (2) H. I. Nirenberg. Releases Fed. Biol. Res. Ctr. Agric. For. (Berlin-Dahlem) 169:1, 1976. (3) D. A. Sampietro et al. Fung. Biol. 114:74, 2010. (4) S. A. Stenglein et al. Plant Dis. 94:783, 2010.

RESUMEN

OBJECTIVE: To determine factors associated with baseline neurocognitive performance in HIV-infected participants enrolled in the Strategies for Management of Antiretroviral Therapy (SMART) neurology substudy. METHODS: Participants from Australia, North America, Brazil, and Thailand were administered a 5-test neurocognitive battery. Z scores and the neurocognitive performance outcome measure, the quantitative neurocognitive performance z score (QNPZ-5), were calculated using US norms. Neurocognitive impairment was defined as z scores <-2 in two or more cognitive domains. Associations of test scores, the QNPZ-5, and impairment with baseline factors including demographics and risk factors for HIV-associated dementia (HAD) and cardiovascular disease (CVD) were determined in multiple regression. RESULTS: The 292 participants had a median CD4 cell count of 536 cells/mm(3), 88% had an HIV viral load < or =400 copies/mL, and 92% were taking antiretrovirals. Demographics, HIV, and clinical factors differed between locations. The mean QNPZ-5 score was -0.72; 14% of participants had neurocognitive impairment. For most tests, scores and z scores differed significantly between locations, with and without adjustment for age, sex, education, and race. Prior CVD was associated with neurocognitive impairment. Prior CVD, hypercholesterolemia, and hypertension were associated with poorer neurocognitive performance but conventional HAD risk factors and the CNS penetration effectiveness rank of antiretroviral regimens were not. CONCLUSIONS: In this HIV-positive population with high CD4 cell counts, neurocognitive impairment was associated with prior CVD. Lower neurocognitive performance was associated with prior CVD, hypertension, and hypercholesterolemia, but not conventional HAD risk factors. The contribution of CVD and cardiovascular risk factors to the neurocognition of HIV-positive populations warrants further investigation.

Asunto(s)

Enfermedades Cardiovasculares/psicología , Cognición/fisiología , Infecciones por VIH/psicología , Seropositividad para VIH/psicología , Hipercolesterolemia/psicología , Adulto , Australia , Brasil , Enfermedades Cardiovasculares/complicaciones , Enfermedades Cardiovasculares/virología , Femenino , Infecciones por VIH/complicaciones , Infecciones por VIH/virología , Seropositividad para VIH/complicaciones , Seropositividad para VIH/virología , Humanos , Hipercolesterolemia/complicaciones , Hipercolesterolemia/virología , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , América del Norte , Análisis de Regresión , Factores de Riesgo , Tailandia

RESUMEN

In Argentina, hop downy mildew disease caused by Pseudoperonospora humuli first appeared in Alto Valle of Rio Negro and Neuquen (1957), Mar del Plata (1962), and El Bolson (1963) (1). The disease occurred in the hop (Humulus lupulus L.) planting areas of El Bolson (Rio Negro) and Lago Pueblo (Chubut) in 2002 and 2003. Surveys were conducted in 30 commercial hop fields from December 2002 to March 2003 to estimate disease incidence and susceptibility of cultivars planted in these fields. Hop fields were divided into five sections and 100 plants were randomly selected and assessed for the presence of disease. Symptoms that were observed in early spring included dark brown rootstocks and primary basal spikes (stunted plants with pale and curled leaves), which are characteristic of systemic infection. Later in the season, secondary infections were characterized by dark purple-to-black lesions on leaves, flowers, cones, and lateral and terminal spikes. Plant symptoms and fungal morphological markers (dichotomously branched sporangiophores; ellipsoid and papillate sporangia) agreed with hop downy mildew disease and the fungus P. humuli. Yield loss was estimated as the reduction in yield compared with the 2001-2002 season observed from five hop growers. On December 10, 70% of the hop fields had greater than 50% disease incidence and seven fields reached 100% incidence. The reduction in cone yield varied between 20 and 34% in fields without a rootstock fungicide treatment. One field with a rootstock fungicide treatment (mefenoxam, copper oxiclorure, phosphorous acid, copper sulfate, and fosetyl-Al) and regular fungicide applications had a 30% increase in cone yield compared with 2001-2002. Systemically infected plants were recorded for hop cvs. Bullion, Cascade, CEZ, GS-19, Hallertauer Mfr., Nugget, Spalt, and Traful. Previously, Cascade was rated as a resistant cultivar to the root systemic infection (1). To our knowledge, this is the first record of a hop downy mildew outbreak in Argentina during the last 30 years. Reference: (1) L. Leskovar. El Lúpulo: Su Cultivo y Procesamiento. Hemisferio Sur. Buenos Aires, 1978.

RESUMEN

In the fall of 2003, severity of late leaf rust in leaves and fruits of red raspberry (Rubus idaeus L.) reached 50% in Buenos Aires (Azul, Baradero, Capilla del Señor, Gral. Rodríguez, Mar del Plata, and Tandil), Córdoba (Villa de Las Rosas), and Entre Ríos (Concordia). The south of Argentina, Río Negro (El Bolsón), and Chubut (El Hoyo, Lago Puelo) remained rust free. The abaxial side of the field infected leaves had pustules filled with masses of yellow spores. Chlorotic areas corresponded in the adaxial side. Urediospores were vacuum harvested from field infected leaves collected in the Tandil area and placed onto a healthy 1-year-old greenhouse-grown plant (cv. Heritage). Spores from a single pustule were increased on plants of the same cultivar. Spores were studied with optic and electronic microscopy. Uredial ostiolar cells were warted, laterally free, and constricted in the middle. The obovoid, echinulate urediospores, from infected leaves averaged 24 × 16 µm (16 to 30 × 11 to 21 µm). Morphological characteristics and spore measurements agreed with those reported for Pucciniastrum americanum (1). Urediniospores were suspended in mineral oil and sprayed onto three raspberry cultivars that were maintained in a darkened mist chamber at 20°C for 48 h and the transferred to a 20°C and 12-h light cycle chamber. Control plants were inoculated with sterile water. There were three replicate plants of each treatment. After 11 days, large sporulating uredia (0.5 mm) were produced on inoculated leaves of cv. Autumn Bliss and smaller uredia (0.1 to 0.3 mm) were produced on cv. Heritage. There were necrotic flecks and the least and smallest uredia were produced on cv. Himbo Queen. No symptoms were present in control plants. To our knowledge, this is the first report of P. americanum causing disease on raspberry in Argentina. Reference: (1) G. F. Laundon and A. F. Rainbow. Pucciniastrum americanum. No. 210 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, England, 1969.

RESUMEN

Blueberries (Vaccinium corymbosum) have recently become an important alternative crop in different ecological regions of Argentina. In surveys, a new disease characterized by leaf spots and twig and shoot blight has been observed on plants cultivated in Arrecifes, Mercedes, and San Pedro (provinces of Buenos Aires) and Concordia (province of Entre Ríos) since July 2004. Spots initially appear brown, circular, 1 to 2 mm in diameter, and irregularly distributed on the leaves and they eventually coalesce. Fruiting twig and shoot blight developed from the tips toward the base. Affected plants of cvs. O'Neal and Reveille were distributed randomly in the field and with a low incidence (average of 2%). The objective of this work was to identify the causal agent of this disease. Symptomatic plant material was surface disinfested with 0.2% NaOCl for 1 min and 70% ethanol for 1 min, washed once with sterile distilled water, blotted dry with paper towels, and plated on potato dextrose agar. Colonies were initially white, becoming light to dark gray with the onset of sporulation with black, sphaerical to subsphaerical conidia that measured 14 to 19 × 12 to 16 µm. These characteristics agree with published descriptions of Nigrospora sphaerica (Sacc.) Mason (1,4). To evaluate pathogenicity, all leaves, petioles, and stems of seven healthy potted plants of cv. O'Neal were punctured with flamed needles and sprayed with a suspension of 1 × 108 spores of the fungus per milliliter of sterile distilled water. Another seven nonwounded plants were sprayed with the spore suspension. Seven plants similarly injured and seven nonwounded plants were sprayed with sterile distilled water and served as controls. Each plant was covered with a water-sprayed polyethylene bag and maintained in a controlled environment chamber at 20°C with a 12-h photoperiod. The bags were removed after 3 days. All wounded inoculated plants began to show disease symptoms similar to those observed in the field 20 days after inoculation. Controls and nonwounded inoculated plants remained symptomless. The pathogen was reisolated from diseased tissues fulfilling Koch's postulates. N. sphaerica is a well-known saprophyte on many plant species but has been mentioned as pathogen on many hosts (2,3). To our knowledge, this is the first reference of N. sphaerica as a wound pathogen of blueberry. In the field, the fungus would have gained access to the plant through wounds caused by insects or frost after a long-term wetness duration. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN, 1989. (3) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA. 2007. (4) E. W. Mason. Trans. Brit. Mycol. Soc. 12:152, 1927.

RESUMEN

A perennial ryegrass (Lolium perenne L.) lawn located at Castelar (Buenos Aires Province) showed disease symptoms during the summer of 2003. Chlorotic patches as much as 15 cm in diameter appeared on the lawn. Later, dead plants with white mycelia developing on the crown and surrounding soil occurred at the periphery of the rings. Plants showed leaf chlorosis and crown and root rot. No sclerotia developed on plant organs. Diseased plants were collected, washed with running tap water for 4 h, and disinfested in 5% NaOCl for 2 min. Pieces, 3 to 5 mm long from symptomatic leaves, crowns, and roots, were incubated on 2% potato dextrose agar (PDA) at 22 to 25°C with a 12-h light/dark cycle. Mycelia growing on the soil surface was transferred to PDA and incubated under the same conditions. After 3 to 4 days, white, conspicuous mycelia that produced sclerotia grew from diseased tissue pieces and soil mycelial samples. Sclerotia were nearly spherical, 1 to 2 mm in diameter, white but turning brown with age, and produced in large numbers over the entire colony surface. Primary hyphae showed clamp connections at the septa. A pathogenicity test was performed with 20 1-month-old plants of L. perenne grown in a 1:1 (v/v) mixture of sand and soil contained in 24- × 17- × 4-cm plastic trays. Seven-day-old fungal cultures grown on PDA were cut into 1- cm2 pieces and placed among the plants on the substrate. Each tray was inoculated with seven inoculum pieces. Five trays of plants were inoculated with the fungus, and plants in five trays that served as controls had only sterile pieces of PDA placed on the substrate. All plants were maintained at 25°C and watered frequently. First symptoms, consisting of chlorosis, were observed 4 days after inoculation. Of the plants, 34, 59, 60, 65, and 70% developed symptoms 6, 9, 14, 17, and 21 days after inoculation, respectively. Control plants remained healthy. The fungus was reisolated from diseased plants and identified as Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) C.C. Tu & Kimbr.) on the basis of morphological and cultural characteristics (3,4). The disease has been observed causing stalk rot on perennial ryegrass in the United States (1) and Australia (2). To our knowledge, this is the first report of S. rolfsii causing disease on L. perenne in Argentina. References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society. St. Paul, MN. 1989. (2) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA, 2007. (3) J. E. M. Mordue. No. 410 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, UK, 1974. (4) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996.

RESUMEN

Blueberry plants with root rot and sudden death symptoms were collected in Concordia, Entre Ríos. Diseased roots were disinfected by immersion in 0.5% NaOCl for 2 min, cut into pieces, transferred to carrot agar (CA), and maintained at 20 ± 2°C and 12 h of near UV light (Philips Black Light lamps TL 40W/08). Conidia were identified with an Olympus BX-51 optical microscope by using a CoolSNAP Pro digital kit with image-pro plus and color digital camera (Media Cybernetics, Inc., Silver Spring, MD). Macroconidia length was variable, 3.9 µm and as much as 29 µm (1 to 5 septa), and microconidia measured 3.8 × 11 µm. Fungal description agrees with Fusarium solani (1). Pathogenicity of the purified isolate was evaluated on 2-month-old plants (cvs. Misty and Sharp Blue). The purified, grayish white isolate was grown on CA for 7 days, and mycelial plugs were placed next to the base of wounded stem and roots immediately below the potting mix soil line. Plants were maintained in the dark at 20 ± 2°C and 90% humidity for 48 h, and then transferred to 12 h of light. Wounded plants with CA plugs served as controls. Dark spots along the stem and root and stem rot appeared 7 to 21 days after inoculation. Controls remained symptomless. The fungus was reisolated from inoculated plants. Fusarium sp. was previously cited (2). To our knowledge, this is the first report of F. solani on blueberry in Argentina. References: (1) C. Booth. Fusarium. Laboratory Guide to the Identification of the Major Species. CMI, Kew, England, 1977. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.

RESUMEN

Night-blooming cereus (Hylocereus undatus A. Berger) is generally used as rootstock of ornamental cactus because of its rapid growth and tolerance to humid substrates. Since 2002, in Gran Buenos Aires, a new disease has been observed in grafted crops in all production stages. Incidence was as much as 30% in many greenhouses. Symptoms consisted of soft rot that started near the soil line and developed upward until it affected all the rootstock. The scion was not rotten, but died as a consequence of rootstock infection. All the roots were symptomless. For pathogen isolation, symptomatic tissues were surface disinfected by a 1-min immersion in 0.2% NaOCl, placed on potato dextrose agar (PDA), and incubated at 22 ± 2°C. Only a Fusarium spp. was consistently isolated in pure culture. Twenty healthy potted night-blooming cereus plants, 10 of them previously injured with needles on the rootstock near the soil line, were gently removed from the substrate and inoculated by a 1-min immersion of their base in a suspension of 1.4 × 106 conidia per ml of sterile distilled water, prepared from 15-day-old cultures. Ten control plants, five of them previously injured, were immersed in sterile distilled water. Inoculated and noninoculated plants were replanted in the original substrate, placed in a climatic chamber at 22 ± 2°C, and monitored for disease expression. Basal rot was observed on all injured inoculated plants 12 days after inoculation. Symptoms on undamaged plants appeared 22 days after inoculation. After 72 days of incubation, all inoculated plants were totally rotten. Control plants remained symptomless. The same pathogen was reisolated to fulfill Koch's postulates. For species identification, single-spore cultures were grown on PDA and carnation leaf agar in a climatic chamber at 23 ± 2°C with a 12-h darkness/near ultraviolet light regimen. The micromorphology and culture features, mainly conidial ontogeny, were consistent with descriptions of Fusarium oxysporum Schlechtend.:Fr. (1). The pathogen was able to penetrate undamaged tissues. Needle injuries accelerated infection. To our knowledge, this is the first report of Fusarium oxysporum on H. undatus in Gran Buenos Aires, Argentina. A culture of the pathogen was deposited at the fungal collection of PRHIDEB-CONICET (University of Buenos Aires) as BAFCult 3158. Reference: (1) P. E. Nelson et al. Fusarium species. An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, PA, 1983.

RESUMEN

Lolium perenne L. is commonly used alone or in association with blue-grass and fescues in sport fields, parks, and gardens. During 2003, symptoms of an unknown disease were observed on L. perenne turfgrass in western Buenos Aires. Initial symptoms were indefinite yellow and green dappled spots that extended downward from the leaf tip, turned brown and finally gray, causing leaf death. Segments of symptomatic leaf tissues were surface sterilized and placed on 2% potato dextrose agar in petri dishes. After 4 days at room temperature, blackish brown colonies developed with dark brown septate conidiophores. Conidia were 21 to 29 × 9 to 13 µm, 3-septa, curved at the third cell from the base that is longer and darker than the others. Cells at each end are subhyaline and intermediate cells are medium brown. These characteristics are consistent with Curvularia lunata (Wakker) Boedijng (1). Pathogenicity tests were performed in five plastic trays with substrate of natural soil and sand (1:1 [v/v]) where the turfgrass (L. perenne cv. El Cencerro) was seeded. Plants were inoculated by spraying a suspension of 2 × 106 conidia per ml of sterile distilled water. Controls were sprayed with sterile distilled water. The trays were covered with transparent plastic bags, sprayed periodically with water, and incubated at 25°C in a greenhouse for 20 days. The first symptoms were observed 3 days later. After 9 days, 24% of the grass surface area showed blight lesions. C. lunata was consistently reisolated from affected tissues. Control plants remained symptomless. To our knowledge, this is the first report of C. lunata affecting L. perenne in Argentina. Reference: (1) M. B. Ellis and I. A. S. Gibson Cochliobolus lunatus (conidial state: Curvularia lunata). Page 474 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1975.

RESUMEN

Rose (Rosa sp.) is one of the most important ornamentals in Argentina. Since 2002, a severe disease has been observed on crops cultivated for cut flowers and garden plants in Escobar, San Pedro, Río Negro, and the surrounding area of Buenos Aires and La Plata. Symptoms consisted of a stem dieback progressing to plant death. In some cases, stem cankers were observed on the dieback limits. Mean incidence of stem dieback was 8% regardless of location. The disease was associated with pruning or harvest wounds. The objective of this study was to identify the causal agent of the described symptoms. Small pieces of diseased tissues from cvs. Rafaela, Merlise, Confeti, Mini rosal, Exótica, Macarena, and Peckowo were surfaced sterilized with a 2-min immersion in 0.2% NaOCl, washed with sterile distilled water, the tissue blotted dry, placed on 2% potato dextrose agar (PDA), and incubated at 22°C. Pure salmon-colored fungal colonies developed within 72 h. Hyaline, two-celled (the upper cell slightly larger), ovoid to ellipsoid conidia formed in chains at the apex of simple, long, slender, septate conidiophores. These characteristics are consistent with the description of Trichothecium roseum (Pers.) Link ex Gray (1) The pathogenicity tests were carried out on 10 plants of cv. Rafaela and 10 plants of cv. Mini Rosal using a conidial suspension (2.4 × 105 spores/ml). All plants were pruned just before inoculation. Another 10 pruned plants (five from each cultivar) were sprayed with sterile water and served as controls. Inoculated and noninoculated plants were placed in a climatic chamber at 20°C and covered with polyethylene bags for 3 days to achieve a humid environment. Stem dieback was evident 7 days after inoculation on both cultivars and cankers appeared in 14 days. A dense, white mold that turned salmon-pink covered all the stems within 25 days. Inoculated plants died after 40 days. Symptoms did not develop on the control plants. The pathogen was recovered from inoculated stems, thus fulfilling Koch's postulates. To our knowledge, this is the first report of T. roseum causing a disease on rose in Argentina. Reference: (1) K. H. Domsch et al. Compendium of Soil Fungi. Academic Press. London, 1980.

RESUMEN

Since 2003, a new field disease has been observed on several cultivars of highbush blueberry (Vaccinium corymbosum L.) in Buenos Aires (Baradero, Colonia Urquiza, Lima, Mercedes, and San Pedro), Entre Ríos (Concordia, Gualeguaychú, and Larroque), and Córdoba (Capilla del Monte and La Cumbre). Infected flowers turned brown to tan with a water-soaked appearance and shriveled up. Blighted flowers typically did not produce fruits; even an entire cluster of berries could be aborted. A chlorotic area, that later became necrotic and turned light brown, developed when leaves were in contact with blighted flowers. A watery rot developed on fruit occasionally before harvest but more generally after harvest. Infected tender green twigs also became blighted, with leaf tissue becoming brown to black. Older twigs and stems were also blighted. Abundant, gray mycelium with conidial masses developed on all affected tissues under moist conditions. Sections of infected leaves, twigs, stems, flowers, and fruits were surfaced sterilized with 0.2% NaOCl, plated on 2% potato dextrose agar (pH 7), and incubated at 22°C. Pure cultures formed a whitish dense mycelial mat and turned gray after 72 h. Conidia were ellipsoid, hyaline, nonseptate, and formed on botryose heads. They ranged from 5.8 to 9 × 8.1 to 13.7 µm (average 8.6 × 10.2 µm). Black, round, and irregular microsclerotia developed on 7-day-old cultures with an average size of 1.1 × 1.7 mm. Morphological characteristics agree with those described for Botrytis cinerea Pers.:Fr (1). Pathogenicity was tested on 10 12-month-old potted blueberry plants cv. O'Neal by spraying a suspension of 1 × 106 conidia per ml of sterile distilled water. Ten plants used as controls were sprayed with sterile distilled water. Each plant was covered with a transparent polyethylene bag for 48 h and incubated at 20 ± 2°C in humid chambers for 15 days. Lesions similar to those observed in the fields developed after 4 days and asexual fructifications developed after 5 days. The same pathogen was reisolated from the lesions, thus completing Koch's postulates. Water-treated plants remained symptomless. To our knowledge, this is the first report of a disease caused by B. cinerea on blueberry in Buenos Aires, Córdoba, and Entre Ríos provinces of Argentina. References: (1) M. V. Ellis and J. M. Waller. Sclerotinia fuckeliana (conidial state: Botrytis cinerea) No. 431 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1974.

RESUMEN

Pelargonium spp. are perennial ornamental plants used as potted plants or bedding plants in gardens. During the spring and summer of 2003, symptoms of an unknown disease appeared on florists' geranium (Pelargonium inquinans (L.) L'Herit) and ivy geranium (P. peltatum (L.) L'Herit.) adult plants growing in gardens in the suburbs of Buenos Aires. Flowers showed small, water-soaked spots that expanded and eventually blighted the petals. Brown, circular to irregular, water-soaked spots developed in leaves and advanced into the peduncules. A fungus was isolated from diseased leaf tissue on potato dextrose agar after surface disinfestations in 2% NaOCl for 2 min. Pure cultures formed a whitish, dense mycelial mat and turned gray after 72 h. Conidia were ellipsoid, hyaline, nonseptate, and were formed on botryose heads with an average size of 8.6 × 10.2 µm. Black, round, and irregular sclerotia developed on 7-day-old cultures with an average size of 1.1 × 1.7 mm. Morphological characteristics agree with those described for B. cinerea Pers.:Fr (1). Pathogenicity tests were conducted. Five 3-month-old plants of each host were spray inoculated with a conidial suspension (1 × 106 conidia/ml). Three controls of each host were sprayed with sterile distilled water. Plants were covered with plastic bags for 48 h and incubated at 20 ± 2°C with natural light for 15 days. Lesions similar to those observed in natural infection developed after 4 days. B. cinerea was reisolated from lesions, thus completing Koch's postulates. Controls remained symptomless. To our knowledge, this is the first report of B. cinerea causing a disease on Pelargonium. spp. in Argentina. Reference: (1) M. V. Ellis and J. M. Waller. No. 431 in: Descriptions of Pathogenic Fungi and Bacteria. CMI. Kew, Surrey, UK, 1974.

RESUMEN

Three ornamental species, Osteospermum sp. (L.), Felicia amelloides (L.) Voss, and Ranunculus asiaticus L., cultivated in greenhouses on the outskirts of Buenos Aires, showed sudden wilt and death during October 2002. These species are new ornamentals in Argentina. The diseased plants were cultivated in plastic containers filled with commercial potting mix. Soft rot was observed at the base of the plants. Stem lesions became covered with whitish mycelium that produced large, black sclerotia (5 to 7 mm in diameter) characteristic of Sclerotinia sclerotiorum (Lib.) de Bary (1). The fungus was consistently recovered from infected stem pieces that were disinfested for 1 min in 0.2% NaOCl and plated on potato dextrose agar (PDA), pH 7. Pathogenicity of the three isolates obtained from infected plants was confirmed by inoculating 10 3-month-old healthy plants of each species in 14-cm-diameter plastic pots. Each isolate was inoculated on the host from which it had been isolated. Inoculum consisted of three mycelial plugs from 7-day-old PDA cultures that were placed on the substrate at the base of the plants. Control plants were treated with sterile agar plugs. Inoculated and noninoculated plants were covered with transparent plastic bags for 2 days and incubated in a growth chamber at 20 to 24°C with a 12-h photoperiod. All inoculated plants developed symptoms of leaf yellowing and wilt. Soft and watery tissues were observed at the base of the plants, soon followed by the appearance of white mycelium. Disease symptoms were similar to those observed on the original infected plants and appeared 6, 5, and 3 days after inoculation on Osteospermum sp., F. amelloides, and R. asiaticus, respectively. All inoculated plants died within 3 weeks, and control plants remained healthy. S. sclerotiorum was reisolated from inoculated plants of each species, fulfilling Koch's postulates. To our knowledge, this is the first report of the occurrence of Sclerotinia stem rot on these three plant species in Argentina. Reference: (1) J. E. M. Mordue and P. Holliday. No. 513 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK. 1976.

RESUMEN

Disease symptoms have been observed since October 1997 on highbush blueberry (Vaccinium corymbosum L.) cvs. Georgia Gem, O'Neal, and Sharpblue cultivated in Buenos Aires. Lesions were observed on recently planted, as well as mature plants, in commercial fields. Circular-to-irregular, light brown-to-gray leaf spots with brownish red borders, initially 3 to 7 mm in diameter, enlarged and coalesced. Blight developed on twigs. Reddish circular spots appeared on stems, developing small cankers. Dark sunken lesions were observed on attached ripening berries. During December 2002, postharvest fruit rot was noted. Small pieces of diseased leaves, twigs, stems, and fruits were surface sterilized with 0.2% NaOCl, plated on 2% potato dextrose agar (pH 7), and incubated at 20 ± 3°C. Symptomatic fruits were placed in plastic trays in humid chambers. In all cases, olive mycelium developed after 3 days with septate hyphae and abundant ovoid and obclavate muriformly septate conidia. The isolate obtained from diseased leaves of cv. O'Neal was used to test pathogenicity on micropropagated potted plants of 20-cm height and ripe fruits contained in plastic trays. Both plants and fruits belonged to cv. O'Neal. A suspension of 2 × 105 conidia per ml was sprayed on needle-punctured young stems, fully expanded leaves, and mature fruits. Plants and trays were covered with polyethylene bags and kept at 24 ± 3°C under fluorescent light (12-hr photoperiod). The bags were removed after 72 hr. Symptoms appeared after 3 days on fruits and 8 days on leaves and stems. Controls remained symptomless. The inoculated pathogen was recovered from diseased organs and identified as Alternaria tenuissima (Kunze:Fr.) Wiltshire (1). To our knowledge, this is the first report on the presence of A. tenuissima affecting blueberry crops in Argentina. Reference: (1) E. G. Simmons. Mycotaxon 70:325, 1999.

RESUMEN

During the summer of 2000, circular, yellow-to-brown, blighted, 2- to 4-cm-diameter patches were observed on creeping bentgrass (Agrostis stolonifera) putting greens (cv. Pennlinks) maintained at a 4- to 5-mm height on a golf course in Pilar (Buenos Aires, Argentina). Symptomatic leaves had transverse chlorotic bands that sometimes extended to the tip with brown lesions inside the bands. A fungus was isolated from symptomatic tissue after surface sterilization with 2% bleach for 1 min and plating on 2% potato dextrose agar (PDA). The mycelium was fluffy and white. The culture turned olive to brown and developed black stromata on the lower side of the plate base after 2 weeks. Pathogenicity tests were performed on 2-month-old healthy plants of A. stolonifera (cv. Crenshaw) grown in sterilized sand. Recently cut, 14-mm-diameter plugs of A. stolonifera were placed in 22- × 17-cm plastic trays filled with a sterilized mixture of 50:50 soil/sand (vol/vol). Plants were maintained at a 7-mm height. Two sources of inoculum were prepared; one was cultured on PDA at 22 to 25°C for 10 days and the other was prepared by incubating in sterilized soil at room temperature for 14 days. Twenty pieces of 1-cm-diameter agar blocks containing mycelium were placed in each plug at the base of the plants. In the infested soil inoculation, 25 g of soil were distributed among the plants on the substrate surface. Control plants were treated with either sterile PDA pieces or noninfested soil. The trays were irrigated with sterilized distilled water, covered with polyethylene bags, and kept in a controlled environment chamber at 25°C with 12 h per day of fluorescent light for 30 days. Leaf chlorosis appeared 7 and 10 days after inoculation for the agar-plug and infested-soil methods, respectively. Leaf necrosis was observed at day 23. Controls remained asymptomatic. The inoculated fungus was reisolated from symptomatic leaf tissue. The pathogen was identified as Sclerotinia homoeocarpa (1,2). To our knowledge, this is the first report of Sclerotinia homoeocarpa causing dollar spot disease on Agrostis stolonifera in Argentina and the first report of a disease on golf courses in our country. References: (1) J. E. M. Mordue. Sclerotinia homoeocarpa. No. 618 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1979. (2) R. W. Smiley. Dollar Spot. Pages 14-16 in: Compendium of Turfgrass Diseases. The American Phytopathological Society, St. Paul, MN, 1983.

RESUMEN

Common garden petunias (Petunia × hybrida Hort. Vilm.-Andr.) are herbaceous annual plants with brightly colored flowers up to 10 cm in diameter. During the winter of 2002, crown and root rot were observed on plants (cv. Ultra) growing in five greenhouses in Buenos Aires. Affected plants were randomly distributed in the greenhouses, and mean disease incidence in all the greenhouses was 26%. Basal leaves turned yellow and gradually became necrotic, and infected plants were often killed. Small pieces of affected tissues were disinfested in 2% sodium hypochlorite for 1 min and plated on 2% potato dextrose agar (PDA). Fifteen isolates identified to the genus Rhizoctonia were obtained. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Hyphal branched at right angles, were constricted at the base of the branch near the union with main hyphae, and septate near the constriction. Basidia were not observed in the greenhouses or on the plates. Isolates were cultivated on water agar and incubated at 25°C for 3 days. Hyphal cells were determined to be multinucleate when stained with 1% aniline blue solution (2) and examined at ×400. Anastomosis group of one isolate was determined by using AG-4 HG II, AG-1 IA, AG-1 IB, AG-1 IC, AG-2 2-1, and AG-2 2IIIB tester strains of Rhizoctonia solani that includes isolates reported to be pathogenic on ornamentals (1). Anastomosis was observed only with strains of AG-4 HG II. Pathogenicity on this isolate was conducted on potted, healthy, adult plants that were 10 to 22 cm high and flowering. Thirty-five plants were inoculated by placing 1 cm2 pieces of PDA from 7-day-old mycelial cultures near the base of the stem. Twelve control plants were treated with 1 cm2 PDA plugs. Plants were kept at 22 to 24°C, >95% relative humidity, and 12 h of fluorescent light. Wilt symptoms due to basal stem rot appeared 7 days after inoculation, and all the inoculated plants died within 27 days. Control plants remained disease free. The pathogen was reisolated from symptomatic tissues, completing Koch's postulates. To our knowledge, this is the first report of R. solani causing disease on petunia in Argentina. References: (1) D. M. Benson and D. K. Cartwright. Ornamental diseases incited by Rhizoctonia spp. Pages 303-314 in: Rhizoctonia species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. B. Sneh et al., eds. Kluwer Academic Publishers, London, England, 1996. (2) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.