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1.
Arch Soc Esp Oftalmol (Engl Ed) ; 93(5): 225-230, 2018 May.
Artículo en Inglés, Español | MEDLINE | ID: mdl-29258782

RESUMEN

INTRODUCTION: Vogt-Koyanagi-Harada disease is a multisystem disorder characterized by a bilateral granulomatous panuveitis. Multiple therapeutic regimens have been used to control inflammation in acute uveitic stage to prevent irreversible visual loss. The purpose of this paper is to compare the effect, on functional and anatomic outcomes, of early treatment with standard corticotherapy vs. corticotherapy plus immunosuppressive (IMT) therapy in acute Vogt-Koyanagi-Harada disease (Group A vs Group B). METHODS: A retrospective chart review of patients with Vogt-Koyanagi-Harada disease, with an evolution time of 2 weeks or less, who attended the Inflammatory Eye Disease Clinic, from 2001 to 2015. Data collected included demographic information, presenting features, treatment and improvement in visual acuity (VA). RESULTS: Sixteen charts were reviewed; 15 females (93.75%). Mean age: 30.81±10.53 years, follow-up time (months): 54.94±43.43. Ten patients (66.6%) had IMT, azathioprine, methotrexate and cyclophosphamide. In group A, initial VA<20/200 in 66.7%; final VA was ≥20/40 in 9 eyes (75%). In group B, initial VA<20/200 in 65%; final VA≥20/40 in 15 eyes (75%). In group A, VA improved faster at one and 3 months (ANOVA P<.057). Clinical characteristics in convalescent stage and complications were similar. Anterior chamber recurrences occurred in both groups and posterior pole recurrences were observed in group A. Time to first recurrence was similar (P<.279). Frequency of recurrence was 2.33±1.80 vs 1.5±0.79 (P<.01). At recurrence 15 patients were still having oral steroids, nine in group A, 6 in Group B. In group A, prednisone was given during more time: mean 15.17±12.08 months, and time to reach to 10mg dose was longer: 8.60±11.7 (P<.008 and P<.046). CONCLUSIONS: Adding IMT as first line therapy to corticosteroids, do not matter significantly in terms of final VA or development of visually significant complications. In the IMT plus corticosteroids group number of recurrences was significantly lower, and a steroid sparing effect was evident.


Asunto(s)
Glucocorticoides/administración & dosificación , Inmunosupresores/administración & dosificación , Síndrome Uveomeningoencefálico/tratamiento farmacológico , Enfermedad Aguda , Adolescente , Adulto , Niño , Quimioterapia Combinada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
2.
Theor Appl Genet ; 123(6): 1029-41, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21744229

RESUMEN

Tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease of wheat worldwide. Host plant resistance is the best strategy to manage this disease. Traditionally, bi-parental mapping populations have been used to identify and map quantitative trait loci (QTL) affecting tan spot resistance in wheat. The association mapping (AM) could be an alternative approach to identify QTL based on linkage disequilibrium (LD) within a diverse germplasm set. In this study, we assessed resistance to P. tritici-repentis races 1 and 5 in 567 spring wheat landraces from the USDA-ARS National Small Grains Collection (NSGC). Using 832 diversity array technology (DArT) markers, QTL for resistance to P. tritici-repentis races 1 and 5 were identified. A linear model with principal components suggests that at least seven and three DArT markers were significantly associated with resistance to P. tritici-repentis races 1 and 5, respectively. The DArT markers associated with resistance to race 1 were detected on chromosomes 1D, 2A, 2B, 2D, 4A, 5B, and 7D and explained 1.3-3.1% of the phenotypic variance, while markers associated with resistance to race 5 were distributed on 2D, 6A and 7D, and explained 2.2-5.9% of the phenotypic variance. Some of the genomic regions identified in this study correspond to previously identified loci responsible for resistance to P. tritici-repentis, offering validation for our AM approach. Other regions identified were novel and could possess genes useful for resistance breeding. Some DArT markers associated with resistance to race 1 also were localized in the same regions of wheat chromosomes where QTL for resistance to yellow rust, leaf rust and powdery mildew, have been mapped previously. This study demonstrates that AM can be a useful approach to identify and map novel genomic regions involved in resistance to P. tritici-repentis.


Asunto(s)
Ascomicetos/patogenicidad , Genoma de Planta , Enfermedades de las Plantas/inmunología , Triticum/genética , Triticum/inmunología , Ascomicetos/inmunología , Mapeo Cromosómico , Genes de Plantas , Estudios de Asociación Genética , Marcadores Genéticos , Genotipo , Inmunidad Innata , Desequilibrio de Ligamiento , Fenotipo , Sitios de Carácter Cuantitativo , Triticum/microbiología
4.
Plant Dis ; 91(9): 1105-1108, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30780649

RESUMEN

Management of Cercospora leaf spot, caused by Cercospora beticola, is necessary for the economic production of sugar beet (Beta vulgaris). The objectives of this study were to evaluate the impact of two relative humidity thresholds (87 and 90%) on the daily infection values (DIVs) used to determine when fungicide applications were required, to determine whether current Cercospora management recommendations for northern areas of Minnesota and North Dakota could be used by growers in the southern areas of these states, and to compare the utility of calendar-based fungicide applications with the Cercospora management model. Research was conducted in Breckenridge, MN and St. Thomas, ND in 2003 and 2004. Fungicide applications significantly (P = 0.05) reduced maximum disease severity (ymax) and area under the disease progress curve (AUDPC) when compared with the nontreated control at both locations during 2003 and 2004. Fungicides applied according to DIVs calculated at RH ≥ 87% or RH > 90% gave similar results. The mandatory second fungicide application 14 days after the first application for southern areas did not significantly decrease disease severity or AUDPC, or improve root yield or recoverable sucrose compared with treatments without the mandatory application. This research illustrates that a DIV calculated at RH ≥ 87% would result in similar timing of fungicide applications compared with DIVs calculated at RH > 90%. The results further show that the recommendation of fungicide applications at initial symptom and subsequent applications based on DIV and disease severity should be used for both northern and southern growers. Finally, this research showed that fungicide applications based on the Cercospora management model provided similar, effective disease control with fewer fungicide applications compared with calendar-based applications.

5.
Plant Dis ; 91(2): 191-194, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30781003

RESUMEN

Sclerotinia sclerotiorum is the causal agent of Sclerotinia stem rot (SSR) of canola (Brassica napus). In North Dakota, the leading canola producer in the United States, SSR is an endemic disease. In order to estimate the impact of this disease on canola yield, field experiments were conducted from 2000 to 2004 at several locations in North Dakota and Minnesota. Experimental plots were either inoculated with laboratory-produced ascospores or infected by naturally occurring inoculum in commercial fields. Applying fungicides at different concentrations and timings during the flowering period created epiphytotics of diverse intensities. Disease incidence was measured once prior to harvesting the crop on 50 to 100 plants per plot. Results of the study indicated that 0.5% of the potential yield (equivalent to 12.75 kg/ha) was lost for every unit percentage of SSR incidence (range of 0.18 to 0.96%). Considering the current cost of fungicide applications and the market value of this commodity, a 17% SSR incidence could cause losses similar to the cost of a fungicide application. Additional efforts are required to improve current levels of tolerance of canola plants to this pathogen.

6.
Plant Dis ; 90(12): 1554, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30780987

RESUMEN

Species of the genus Cuphea (family Lythraceae) are being developed as potential domestic sources of medium length fatty acids (lauric and capric) for use in industrial lubricants and detergents. During September 2004, patches of dead plants were observed in test plots of Cuphea sp. cv. PSR-23 (1) (Cuphea viscosissima Jacq. × C. lanceolata W.T. Aiton) near Morris, MN and Prosper, ND, approximately 200 km apart. Seed yield in the diseased Morris field was 78 kg/ha compared with 516 kg/ha in nearby, nonaffected fields of the same variety, for an 85% yield reduction. Stems were split open to reveal long, cylindrical sclerotia as much as 8 mm long. Isolations from diseased stem tissue and sclerotia were identified as Sclerotinia sclerotiorum (Lib.) de Bary and produced typical sized sclerotia (4 to 6 mm in diameter) after 7 days growth on potato dextrose agar (PDA). Cuphea PSR-23 plants were grown in the greenhouse in individual pots for 5 weeks and then inoculated. Three inoculation methods were used. For the first method, ascospores of a sunflower isolate of S. sclerotiorum were sprayed onto blooming flowers and foliage at a rate of 5,000 spores per ml. The inoculated plants were kept in a dark, 18°C mist chamber for 48 h and then returned to a greenhouse maintained at 24/20°C, day/night temperatures. All 20 inoculated plants were visibly colonized by Sclerotinia sp. after 3 days, and all plants were dead by 7 days. The second inoculation used the petiole inoculation technique employed by canola researchers (2). The blade from the third leaf was excised and a micropipette tip containing an agar disk of mycelia of the Cuphea isolate was placed over the cut end of the petiole. Five days after inoculation, all 30 inoculated plants were dead, while none of the 10 control plants (using sterile agar disks on the cut petiole) were affected. Isolations were made from diseased plants inoculated by all methods, and S. sclerotiorum colonies were observed on PDA medium with typical sclerotia from 4 to 6 mm in diameter. The third inoculation method tested root infection. S. sclerotiorum was grown on autoclaved proso millet (Panicum miliaceum L.) seed for 7 days, and 5 g of colonized millet seed was placed in a hole 6 cm from the base of a Cuphea plant, with one plant per 3.7 liter pot. Sunflower (Helianthus annuus L.; oilseed hybrid Cargill 270) plants served as inoculated controls. None of the 20 Cuphea plants were infected via soil inoculations compared with 70% of 30 sunflower plants that developed basal stalk rot and wilt within 2 weeks after inoculation. To our knowledge, this is the first report of S. sclerotiorum infection on Cuphea sp., and is believed to be the first report of infection on any genus within the Lythraceae (loosestrife family). With over 100 annual and perennial species in the genus Cuphea, the possibility of Sclerotinia spp. resistance needs to be investigated to further develop this potential oilseed crop. References: (1) S. J. Knapp and J. M. Crane. Crop Sci. 40:299, 2000. (2) J. Zhao et al. Plant Dis. 88:1033, 2004.

7.
Plant Dis ; 90(7): 946-950, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30781035

RESUMEN

Growth chamber studies were conducted using rehydrated dry bean (Phaseolus vulgaris) flowers (RDBF) to assess the influence of temperature (18 and 22°C), relative humidity (RH; 25 and 90%), and ascospore concentrations (102, 103, and 104 ascospores/ml) on white mold incidence in dry bean. Additional studies were carried out to determine the influence of inoculum type (ascospore and mycelium) and to estimate the effect of duration of drying of colonized RDBF on viability of Sclerotinia sclerotiorum and white mold incidence. There was a linear increase in white mold incidence with increase in ascospore concentration but neither temperature nor RH levels significantly affected disease development. In the inoculum type study, both temperature and RH levels significantly affected white mold incidence; however, neither ascospore nor mycelial inocula had a significant effect on white mold incidence. Drying colonized RDBF for up to 96 h did not affect S. sclerotiorum viability; but the amount of white mold incidence depended more on post-inoculation RH and drying duration than on the temperatures tested. Colonized RDBF dried for 96 h took approximately three times longer to achieve 100% white mold incidence compared with colonized RDBF dried for 24 h. These results suggest the potential for greater white mold development with higher ascospore availability and the potential of dry S. sclerotiorum-colonized dry bean flowers as a viable inoculum source.

8.
Plant Dis ; 90(2): 215-219, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30786415

RESUMEN

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, can be a devastating disease of canola (Brassica napus) in the northern United States. No canola cultivars are marketed as having resistance to SSR. Field trials were established in Red Lake Falls, MN (2001, 2003, and 2004) and Carrington, ND (2001, 2002, 2003, and 2004) to evaluate canola cultivars for resistance to SSR. These cultivars also were evaluated for resistance to SSR under controlled conditions using the following methods: petiole inoculation technique (PIT), detached leaf assay (DLA), and oxalic acid assay (OAA). Significant (P ≤ 0.05) differences were detected among cultivars for SSR and yield in the field trials, with SSR levels varying from low to high among years and locations. Cultivars with consistent high levels and low levels of SSR in the field trials were identified. Significant (P ≤ 0.05) differences were detected among cultivars for SSR using the PIT and OAA methods, but not the DLA method. No significant (P ≤ 0.05) correlations between SSR levels in the controlled studies with SSR levels in the field trials were detected; however, significant negative correlations were detected between SSR area under the disease process curve values from the PIT method and yield from Carrington, ND in 2001 and 2002. Although the PIT and OAA methods differentiated cultivars, neither method was able to predict the reaction of cultivars to SSR in the field, indicating that field screening for SSR resistance is still critical for the development of resistant cultivars.

9.
Plant Dis ; 89(2): 208, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30795241

RESUMEN

Borage (Borago officinalis) is an oilseed crop that is being evaluated as an alternative crop in North Dakota. During September 2004, borage plants in a field in Cass County, North Dakota were dying from a watery soft rot. The main stems and lateral branches were affected, and affected plants were usually completely lodged and prostrate. Dead plants had bleached and shredded stems with black sclerotia (9.1 ± 3.0 × 2.6 ± 0.5 mm) inside the pith and on the epidermis. At the time of observation, borage plants were flowering and forming pods and seed. Approximately 60% of the plants were visually affected by the watery soft rot. Sclerotia were collected from diseased plants, soaked in a 0.5% NaOCL solution for 30 s, air dried, and placed in petri dishes containing potato dextrose agar (PDA). A fungus grew from the plated sclerotia that subsequently produced white mycelium and black sclerotia (4.8 ± 1.2 × 2.5 ± 1.0 mm), which is characteristic of Sclerotinia sclerotiorum (Lib.) de Bary (3). To confirm pathogenicity, borage plants were inoculated in the greenhouse with a S. sclerotiorum isolate from field-infected borage. Thirteen borage plants were grown from seed in the greenhouse under natural sunlight at a temperature range of 24 ± 3°C. When plants were at the four-leaf stage (approximately 16 cm high), the second leaf was excised from each plant with the petiole remaining on the plant. The leafless petioles were inoculated using a method previously described (2). Petioles of 10 plants were inoculated with PDA containing mycelium of the S. sclerotiorum borage isolate, while petioles of five plants were inoculated with PDA to serve as a control. Three days after inoculation, plants inoculated with the S. sclerotiorum borage isolate were beginning to wilt and 5 days after inoculation, these plants were completely wilted and prostrate, similar to observations made on field-infected plants. Sclerotia collected from the diseased, inoculated plants were placed on PDA, and S. sclerotiorum was successfully recovered. Control plants inoculated with PDA did not show any disease symptoms. Other plant genera in the Boraginaceae are known hosts of S. sclerotiorum (1); however, to our knowledge, this is the first report of borage as a host. References: (1) G. J. Boland and R. Hall, Can. J. Plant Pathol. 16:93, 1994. (2) L. E. del Río et al. (Abstr.) Phytopathology 90(suppl.):S176, 2000. (3) D. L. Tourneau, Phytopathology 69:887, 1979.

10.
Plant Dis ; 89(6): 684, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30795405

RESUMEN

Echium, also known as common viper's bugloss, is a member of the botanical family Boraginaceae. Echium is being evaluated for its potential use as an oilseed crop in North Dakota. In 2003, 40% of echium plants in a field in Cass County were observed showing classical symptoms of infection by Sclerotinia sclerotiorum. Plants in advanced stages of infection were dead. Stems of dead plants peeled off easily when touched and numerous cylindrical, black sclerotia that were 2 to 3 mm in diameter and 4 to 7 mm long were found in the pith. Younger stem lesions were watery soft, many of them with a white cottony growth on them. Sclerotia and infected stem tissues collected from the field were surface disinfested in a 0.5% NaOCl solution for 30 s, rinsed with sterile distilled water, and air dried before plating on potato dextrose agar (PDA). Samples were incubated at room temperature for 1 week. White mycelium and black sclerotia, characteristic of S. sclerotiorum (Lib.) de Bary, were produced in all dishes. Koch's postulates were fulfilled using the petiole inoculation technique (2). Briefly, 4-mm agar plugs containing hyphal tips of a 2-day-old S. sclerotiorum colony growing on PDA were excised and loaded in the wide opening of 100-µl pipette tips. The second true leaf of 15 3-week-old echium seedlings, growing in plastic pots containing Ready-Mix soil, was cut off with a razor blade leaving an approximately 25-mm long petiole attached to the stem. The leafless petioles of 10 seedlings were capped with a loaded pipette, agar plug first, until the petiole tip broke the inner surface of the plug and the petiole came in contact with the mycelium. The other five seedlings were inoculated with agar plugs without mycelium and used as control plants. Three days after inoculation, all seedlings inoculated with S. sclerotiorum wilted and expressed symptoms similar to those observed in the field. None of the control plants showed symptoms of infection. Black sclerotia were retrieved from infected stems 2 weeks after inoculation, and the pathogen was successfully reisolated onto PDA. Several important North Dakota crops are susceptible to S. sclerotiorum. The identification of echium as a new host for S. sclerotiorum should be considered in the event that this crop is promoted as an alternative for North Dakota agriculture. To our knowledge, this is the first report on the susceptibility of echium to S. sclerotiorum. Other members of the Boraginaceae have been identified as hosts for this pathogen (1). References: (1) G. J. Boland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (2) L. E. del Río et al. (Abstr.) Phytopathology 91 (suppl.):S176, 2001.

11.
Plant Dis ; 88(12): 1352-1356, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30795197

RESUMEN

Studies on chemical control of white mold, conducted between 1994 and 2001 at several locations in North Dakota, resulted in diverse levels of white mold incidence and severity. Navy bean cultivars were evaluated in on-farm trials between 1994 and 1996, while pinto bean cultivars were used between 1997 and 2001. The relationship between yield and white mold incidence in these trials was examined using correlation and regression analysis. White mold incidence was correlated to severity using a second-degree polynomial equation (R 2 = 0.90, P = 0.0001) in pinto bean experiments. For every percent unit increase in white mold incidence, yield was reduced by 12 kg/ha (range 7 to 19 kg/ha) in pinto bean and by 23 kg/ha (range 19 to 26 kg/ha) in navy bean. In both instances, the coefficients of determination were significant (P < 0.04) for most locations or years, and ranged from 0.42 to 0.87 for pinto bean and from 0.98 to 0.99 for navy bean. Fungicide-protected plots had an average white mold incidence of 34 and 50% compared with 76 and 73% in nonprotected plots for pinto and navy bean, respectively. Fungicide applications increased yields by 33 and 26% (P ≤ 0.05) for pinto and navy bean, respectively.

12.
Plant Dis ; 87(3): 263-265, 2003 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30812758

RESUMEN

Colletotrichum lindemuthianum, causal agent of anthracnose, a serious disease of dry bean, had been prevalent mostly in the eastern United States and Michigan. In 2001, the disease was observed affecting several commercial bean fields in North Dakota. To assess the potential impact of this pathogen on the North Dakota dry bean industry, 30 of the most widely planted cultivars were inoculated with races 7, 73, and 89 of C. lindemuthianum. Race 73 is present in Michigan, and has been detected in recently North Dakota and Manitoba, while races 7 and 89 are currently present in Michigan and Ontario. All cultivars were spray inoculated with a suspension of 106 conidia/ml in the greenhouse and evaluated for disease reaction using a 0-to-9 scale 8 days after inoculation. Most kidney beans were susceptible to race 7, but resistant to races 73 and 89. 'Isles' and 'Drake' were the only kidney beans resistant to all three races. All pinto beans were susceptible to races 73 and 89 except 'Topaz', which was moderately resistant to race 73 but susceptible to race 89. Most pinto beans were resistant or moderately resistant to race 7. Navy bean cvs. Newport and Envoy were resistant to all three races; however, 'Norstar', the most widely planted navy bean cultivar, was susceptible to all three races. Research is being conducted to identify germplasm with resistance to these races. To reduce the possibility of spreading this pathogen to new fields in the region, the use of noncertified seed should be discouraged among producers, and fields used for seed production should be monitored very carefully.

13.
Plant Dis ; 86(9): 971-980, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30818558

RESUMEN

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a major soybean (Glycine max) disease in north-central regions of the United States and throughout the world. Current sources of resistance to Sclerotinia stem rot express partial resistance, and are limited in number within soybean germ plasm. A total of 6,520 maturity group (MG) 0 to IV plant introductions (PIs) were evaluated for Sclerotinia stem rot resistance in the United States and Canada in small plots or in the greenhouse from 1995 to 1997. Selected PIs with the most resistance were evaluated for resistance in the United States and Canada in replicated large plots from 1998 to 2000. The PIs in the MG I to III tests in Urbana, IL were evaluated for agronomic traits from 1998 to 2000. The selected PIs also were evaluated with an excised leaf inoculation and petiole inoculation technique. After the 1995 to 1997 evaluations, all but 68 PIs were eliminated because of their susceptibility to Sclerotinia stem rot. In field tests in Urbana, higher disease severity in selected MG I to III PIs was significantly (P< 0.05) associated with taller plant heights and greater canopy closure. All other agronomic traits evaluated were not associated or were inconsistently associated with disease severity. MG I to III PIs 153.282, 189.931, 196.157, 398.637, 417.201, 423.818, and 561.331 had high levels of resistance and had canopies similar to the resistant checks. The resistance ratings from the petiole inoculation technique had a high and significant (P< 0.01) correlation with disease severity in the MG I and II field tests. The partially resistant PIs identified in this study can be valuable in incorporating Sclerotinia stem rot resistance into elite germ plasm.

14.
Plant Dis ; 86(9): 999-1004, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30818562

RESUMEN

Field studies were conducted to evaluate the effectiveness of Sporidesmium sclerotivorum to control Sclerotinia stem rot of soybean (SSR) at Ames, Humboldt, and Kanawha, IA, between 1996 and 1998. Experimental plots (3 × 3 m) were infested with S. sclerotivorum macroconidia once at a rate of 0, 2, or 20 spores per cm2 in the fall of 1995 or the spring of 1996, under two crop rotation schemes. A randomized complete block design with four replications in each location was used. Plots infested with 20 spores per cm2 had 62% less SSR (P = 0.05) than control plots at Humboldt in 1996. No differences were detected between fall and spring applications. In 1998, plots treated with either 2 or 20 spores per cm2 had 51 to 63% less SSR (P = 0.05) than control plots at Ames and Kanawha. In 1998, SSR was completely suppressed in all plots at Humboldt, while the commercial field surrounding the experimental plots had 17% SSR. S. sclerotivorum was retrieved from all infested plots at all locations 2 years after infestation with sclerotia of Sclerotinia sclerotiorum as bait. At Humboldt, S. sclerotivorum was also retrieved from control plots. Two larger plots (10 × 10 m) were infested with 20 or 100 spores per cm2 in the fall of 1996 or spring of 1997 in six commercial fields. SSR incidence, which was measured in transects up to 20 m from the infested area at 5-m intervals, was reduced 56 to 100% (P = 0.05) in four fields compared with the surrounding uninfested areas in the commercial fields. Dispersal of the control agent was evident by the fact that SSR incidence gradually increased from the edge of the infested macroplots up to about 10 m into noninoculated areas of the commercial field. This paper constitutes the first report describing the biocontrol of a disease on field crops that may be employed economically.

15.
Plant Dis ; 86(5): 562, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-30818696

RESUMEN

Dry bean (Phaseolus vulgaris L. cv. Pintoba) plants showing typical anthracnose symptoms were observed in three commercial fields in North Dakota (Towner, Steele, and Pembina counties) in July 2001. Disease incidence in all fields ranged from 5 to 20%. The fungus was isolated from leaves and pods on potato dextrose agar and identified as Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib. (3). Pathogenicity and race identification were determined on a set of 12 standard differentials (2). Three isolates, one from each county, were grown for 7 days in Mathur's medium. Spores were suspended in water and Tween 80 (0.1% vol/vol) and adjusted to 106 spores per ml. Thirty 2-week-old seedlings of each differential were inoculated with each isolate on the adaxial side of the primary leaves using a Paasche airbrush. Inoculated plants were incubated in moist chambers for 5 days at 20°C under 14 h of fluorescent light and then moved back to the greenhouse. Disease reaction was assessed 3 days later. Isolates of C. lindemuthianum races 7 and 73 obtained from J. Kelly (Michigan State University) were used as positive controls. Inoculations were repeated once. All three North Dakota isolates and the positive control for race 73 produced sporulating lesions on the differentials 'Michelite', 'Cornell 49242', and 'Mexico 222'. No lesions were observed in the other differentials. An unidentified anthracnose race retrieved from a single plant in 1982 constitutes the first report of the presence of anthracnose in North Dakota (4). In 1992, Michigan breeding materials infected with race 73 were planted in North Dakota (1); upon detection, the infected plants were destroyed and the fields quarantined. The epidemics observed in the 2001 season, developed in sites distant from the places where the Michigan materials were planted and have been associated with a single seed source. To our knowledge, the presence of anthracnose race 73 reported here constitutes the first report of anthracnose in commercial dry bean fields in North Dakota. References: (1) J. D. Kelly et al. Plant Dis. 78:892, 1994. (2) M. A. Pastor-Corrales. Phytopathology 81:694, 1991. (3) B. C. Sutton, The Coelomycetes, CAB International, Wallingford, Oxon, UK, 1980. (4) J. R. Venette and P. A. Donald. Bean Improv. Coop. 26:24, 1983.

16.
Mycopathologia ; 129(1): 5-16, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7617016

RESUMEN

Sixty nine samples of maize were collected from pre-harvest standing crops and on-farm storage facilities from 52 smallholder farms located within 4 regions of Honduras during October 1992 and November 1993. Samples were visually assessed for insect damage and fungal spoilage, and the mycoflora quantified on artificial media. The major components of the ear rot complex were: Fusarium moniliforme, F. moniliforme var. subglutinans, Penicillium species, Stenocarpella maydis, S. macrospora and Acremonium spp. Representative samples were also assayed for mycotoxin content. Fumonisin B1 was detected in all 24 samples tested at levels of between 68-6,555 (micrograms/kg), and aflatoxin was detected in 2 samples heavily contaminated with Aspergillus flavus. Moniliformin and tenuazonic acid were not detected in the samples tested. The implications of these findings for human and livestock health risk are discussed, together with possible strategies for controlling these pathogens.


Asunto(s)
Microbiología de Alimentos , Fumonisinas , Hongos Mitospóricos/aislamiento & purificación , Micotoxinas/análisis , Zea mays/microbiología , Aflatoxinas/análisis , Ciclobutanos/análisis , Honduras , Ácido Tenuazónico , Zea mays/química
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