NEMATODE SUSCEPTIBILITY AND SENSITIVITY OF IN VITRO PROPAGATED ‘VALERY’ BANANAS UNDER FIELD CONDITIONS IN COSTA RICA

1998 ◽  
pp. 361-368 ◽  
Author(s):  
D. Waele ◽  
Rony L. Swennen ◽  
E. Boonen
Keyword(s):  
Costa Rica ◽  
Field Conditions

scholarly journals Evaluation of various plant extracts against the early blight disease of tomato plants under greenhouse and field conditions

2012 ◽  
Vol 48 (No. 2) ◽  
pp. 74-79 ◽  
Author(s):  
S.M.A. Nashwa ◽  
K.A.M. Abo-Elyousr
Keyword(s):  
Disease Severity ◽  
Plant Extracts ◽  
Mycelial Growth ◽  
Early Blight ◽  
Field Conditions ◽  
Nerium Oleander ◽  
Tomato Plants ◽  
Infected Control ◽  
Blight Disease

The antimicrobial activity of six plant extracts from Ocimum basilicum (Sweat Basil), Azadirachta indica (Neem), Eucalyptus chamadulonsis (Eucalyptus), Datura stramonium (Jimsonweed), Nerium oleander (Oleander), and Allium sativum (Garlic) was tested for controlling Alternaria solani in vitro and in vivo. In in vitro study the leaf extracts of D. stramonium, A. indica, and A. sativum at 5% concentration caused the highest reduction of mycelial growth of A. solani (44.4, 43.3 and 42.2%, respectively), while O. basilicum at 1% and 5% concentration and N. oleander at 5% concentration caused the lowest inhibition of mycelial growth of the pathogen. In greenhouse experiments the highest reduction of disease severity was achieved by the extracts of A. sativum at 5% concentration and D. stramonium at 1% and 5% concentration. The greatest reduction of disease severity was achieved by A. sativum at 5% concentration and the smallest reduction was obtained when tomato plants were treated with O. basilicum at 1% and 5% concentration (46.1 and 45.2 %, respectively). D. stramonium and A. sativum at 5% concentration increased the fruit yield by 76.2% and 66.7% compared to the infected control. All treatments with plant extracts significantly reduced the early blight disease as well as increased the yield of tomato compared to the infected control under field conditions.

scholarly journals A shorter equilibration period in the VitTrans in-straw bovine embryo vitrification method improves post-warming outcomes

2020 ◽  
Author(s):  
Iris Martínez-Rodero ◽  
Tania García-Martínez ◽  
Erika Alina Ordóñez-León ◽  
Meritxell Vendrell-Flotats ◽  
Carlos Olegario-Hidalgo ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Survival Rates ◽  
Field Conditions ◽  
Bovine Embryo ◽  
Direct Transfer ◽  
Treatment Groups ◽  
Cell Counts ◽  
Hatching Rates

Abstract Background VitTrans is a device that enables the vitrification and warming/dilution of in vitro produced bovine embryos followed by their direct transfer to recipient females in field conditions. This study sought to improve the VitTrans method by comparing two equilibration times: short (SE: 3 min) and long (LE: 12 min). Outcome measures recorded in vitrified D7 and D8 expanded blastocysts were survival and hatching rates, differential cell counts, apoptosis rate and gene expression. Results While survival rates at 3 h and 24 h post-warming were reduced (P < 0.05) after vitrification, hatching rates of D7 embryos vitrified after SE were similar to those obtained in fresh non-vitrified blastocysts. Hatching rates of vitrified D8 blastocysts were lower (P < 0.05) than of fresh controls, regardless of treatment. Total cell counts, and inner cell mass and trophectoderm cell numbers were similar in hatched blastocysts derived from D7 blastocysts vitrified after SE and fresh blastocysts, while vitrified D8 blastocysts yielded lower values, regardless of treatment. The rate of apoptotic cells was significantly higher in both treatment groups when compared to fresh controls, although apoptosis rates were lower using the SE than LE protocol. No differences emerged in expression of the genes BAX, AQP3, CX43 and IFNτ between blastocysts vitrified after SE or LE, whereas a significantly higher abundance of BCL2L1 and SOD1 transcripts was observed in blastocysts vitrified after SE compared to LE. Conclusions The VitTrans device combined with a shorter exposure to the equilibration medium improves vitrification/warming outcomes facilitating the direct transfer of vitrified embryos under field conditions.

scholarly journals Oferta y demanda de estudios de equivalencia terapéutica (in vitro e in vivo) de medicamentos en Costa Rica

2016 ◽  
Vol 29 (1) ◽  
pp. 18
Author(s):  
Zacarías Pereira-Vega
Keyword(s):  
Costa Rica

<p class="p1">El continuo incremento del gasto en medicamentos a nivel mundial, íntimamente asociado al crecimiento poblacional y al aumento de la esperanza de vida de las personas, ha llevado en las últimas décadas a los gobiernos a buscar alternativas que contribuyan a reducir el impacto de este rubro en los presupuestos. Una alternativa es el uso de medicamentos genéricos, que son más baratos que los innovadores. Sin embargo, antes de ser registrado, el producto genérico debe demostrar su equivalencia terapéutica mediante ensayos <em>in vitro </em>y/o <em>in vivo </em>contra un medicamento de referencia, con el propósito de garantizar su calidad, seguridad y eficacia y, como consecuencia de ello, su intercambiabilidad. </p><p class="p1">Mediante una encuesta <em>online </em>realizada en Costa Rica durante los meses de marzo y abril de 2013, se determinó que existía una demanda de 85 medicamentos fabricados en el país, que para ser registrados a nivel nacional requerían de la misma cantidad de estudios de equivalencia terapéutica, de los cuales 47 correspondían a ensayos <em>in vitro </em>y 38 a ensayos <em>in vivo</em>. Esta demanda provenía principalmente de cuatro laboratorios que fabrican medicamentos en Costa Rica, y aumenta si se consideran los medicamentos exportados. En cuanto a la oferta nacional de estos servicios (ensayos <em>in vitro </em>e <em>in vivo</em>) por parte de laboratorios ajenos a la casa fabricante, se sabe que es muy limitada, ya que solo había dos que los ofertaban y su labor se circunscribe, por ahora, a los ensayos <em>in vitro</em>. </p>

scholarly journals Pruebas in vitro de hongos antagonistas para combatir la roya de mora en Costa Rica

2017 ◽  
Vol 41 (1) ◽  
Author(s):  
Konrad Holst Sanjuán ◽  
German Rivera-Coto ◽  
Keylor Villalobos-Moya ◽  
Rafael Orozco-Rodríguez ◽  
Steffany Orozco-Cayasso
Keyword(s):  
Costa Rica ◽  
Colletotrichum Spp ◽  
Para Determinar

El objetivo de esta investigación fue aislar hongos asociados a pústulas de roya (Kuehneola spp.), para seleccionar cepas con algún efecto antagonista sobre el agente causal de esta enfermedad, en 7 localidades de la Zona de Los Santos y Pérez Zeledón, Costa Rica. Se realizaron muestreos en plantaciones de mora cultivadas orgánicamente para obtener distintos hongos y determinar su posible acción antagónica contra el agente causal. El estudio se extendió por espacio de un año (junio 2011-junio 2012), periodo en el cual se realizaron recolecciones mensuales para incluir la mayor diversidad de eventuales biocontroladores durante un ciclo. Del material recolectado se logró aislar un total de 11 géneros diferentes de hongos: Pestalotia spp., Sphaeropsis sp., Botrytis sp., Verticillium sp., Macrophomina sp., Cladosporium spp., Phoma sp., Colletotrichum spp., Rhizoctonia sp., Libertella sp., Paecilomyces sp., y varios micelios estériles no identificados. Para establecer el posible efecto antagonista de los hongos, se realizaron ensayos in vitro con el fin de determinar su capacidad supresora, sobre la germinación de las uredósporas de Kuehneola spp. De todos los aislamientos, los que resultaron significativamente distintos a su respectivo testigo fueron los del género Cladosporium. Para determinar diferencias significativas entre estos aislamientos se realizaron comparaciones entre ellos y se estableció que todos los aislamientos afectaron de igual forma la germinación de uredósporas y solamente Clados4 inhibió por completo la germinación.

scholarly journals Evaluación in vitro de hongos nematófagos en zonas arroceras de Costa Rica contra el nematodo agallador Meloidogyne javanica

1969 ◽  
Author(s):  
Walter Peraza Padilla ◽  
Martha Orozco Aceves ◽  
Alejandro Esquivel Hernández
Keyword(s):  
Costa Rica ◽  
Fusarium Oxysporum ◽  
Meloidogyne Javanica ◽  
Trichoderma Sp

Se evaluó el parasitismo in vitro de 14 aislamientos de hongos nematófagos (6 Trichoderma sp., 4 Paecilomyces sp., 2 Fusarium oxysporum, y 2 Monacrosporium sp.) contra juveniles y huevos del nematodo agallador Meloidogyne javanica. Los hongos, de 3 regiones productoras de arroz en Costa Rica, (Pacífico Central, Huetar Atlántica y Chorotega), se aislaron mediante el método de espolvoreado en placas, durante abril del 2008 a agosto de 2009. Se utilizó un diseño completamente al azar con 10 repeticiones por hongo, en agar-agua (AA). Se inoculó una suspensión de 1 a 1,5x10 6 conidios (ufc.ml -1 ) por plato Petri, y al cuarto día se depositó en 0,5 ml una suspensión de 150 juveniles y 100 huevos de M. javanica previamente desinfectados, a temperatura ambiente (23-26°C) y con luz natural. Transcurridas 96 h se contó en cada plato el número de nematodos vivos, muertos ó parasi- tados y de huevos parasitados o no parasitados. Se realizó un análisis de regresión logística (RL) para las variables evaluadas, el cual mostró diferencias significativas (p<0,0001) en el desempeño de los hongos evaluados, presentando rangos de entre 10% a 56% en nematodos muertos, de 13% a 79% en nematodos parasitados y de 1% a 96% en huevos parasitados. En general, los hongos del género Trichoderma (Tri1, Tri2, Tri3 y Tri4) fueron los más eficientes en el parasitismo sobre juveniles y huevos de M. javanica.

scholarly journals Management of Purple Blotch Complex of Onion in Indian Punjab

2017 ◽  
Vol 5 (4) ◽  
pp. 454-465 ◽  
Author(s):  
Ritesh Kumar Yadav ◽  
Amarjit Singh ◽  
Sandeep Jain ◽  
Ajmer Singh Dhatt
Keyword(s):  
Integrated Management ◽  
Field Conditions ◽  
Cost Ratio ◽  
Seed Crop ◽  
Systemic Fungicides ◽  
Benefit Cost Ratio ◽  
Field Efficacy ◽  
Seed Method ◽  
Benefit Cost

Six systemic fungicides viz.,  Kitazin 48 EC (iprobenfos), Tilt 25 EC (propiconazole), Folicur 25 EC (tebuconazole), Score 25 EC (difenoconazole), Amistar Top 325 SC (azoxystrobin 18.2% + difenoconazole 11.4%) and Nativo 75 WG  (trifloxystrobin 25% + tebuconazole 50%), and two non-systemic fungicides viz., Indofil M-45 75 WP (mancozeb) and Kocide 77 WP (copper hydroxide), were evaluated under in vitro and field conditions for their efficacy to manage purple blotch complex of onion caused by Alternaria porri and Stemphylium vesicarium. Field efficacy of  the fungicides at different concentrations were determined in controlling the purple blotch complex of onion under artificial epiphytotic conditions on bulb and seed crop (cultivar PRO-6) during the Rabi season 2014-2015 and 2015-2016, respectively. The triazole fungicides, tebuconazole and difenoconazole proved superior in inhibiting growth of A. porri and S. vesicarium under in vitro conditions, respectively. Further, foliar sprays (3 for bulb crop and 4 for seed crop) of tebuconazole 25 EC (Folicur) @ 0.1 per cent at fortnightly interval most effectively managed purple blotch complex of onion under field conditions with highest Benefit: Cost ratio (8.75:1 and 88.7:1) in bulb and seed crop, respectively. Seed-to-seed method of onion seed production recorded significantly lower disease severity and higher seed yield than that of bulb-to-seed method under natural epiphytotic conditions. The present findings can be instrumental in devising strategy for the integrated management of A. porri, S. vesicarium singly as well as in complex, serious limiting biotic factors in onion production. Int. J. Appl. Sci. Biotechnol. Vol 5(4): 554-565

Biochar Decreases Atrazine and Pendimethalin Preemergence Herbicidal Activity

2015 ◽  
Vol 29 (3) ◽  
pp. 359-366 ◽  
Author(s):  
Neeta Soni ◽  
Ramon G. Leon ◽  
John E. Erickson ◽  
Jason A. Ferrell ◽  
Maria L. Silveira
Keyword(s):  
Weed Control ◽  
Linear Regression Analysis ◽  
Cropping System ◽  
Herbicidal Activity ◽  
Field Conditions ◽  
Biofuel Production ◽  
Sorption Experiment ◽  
Herbicide Activity ◽  
By Products

Biochar and vinasse are by-products of biofuel production that can be used as soil amendments. However, their addition to the soil might affect PRE herbicide activity. Although studies have shown that biochar has a high herbicide adsorption capacity, there is little information available about biochar effect on weed control especially under field conditions. Therefore, the objective of this study was to determine the influence of biochar and vinasse application on atrazine and pendimethalin availability and herbicide activity underin vitroand field conditions.In vitroatrazine and pendimethalin herbicidal activities were not influenced by vinasse addition, but biochar application reduced atrazine and pendimethalin injury for all evaluated species. A sorption experiment confirmed high affinity of biochar for atrazine and pendimethalin. Linear regression analysis showed that the slope for atrazine and pendimethalin adsorption was 16 and 4 times higher in soil with biochar than in soil alone. Under field conditions, biochar at 0.5 kg m−2reduced atrazine and pendimethalin weed control 75% and 60%, respectively. These results suggested that the use of biochar as a soil amendment in cropping system could decrease PRE herbicide efficacy. Therefore, mitigating practices such as the use of higher rates or reliance on POST herbicides and cultivation might be necessary to ensure proper weed control.

Binary combinations of thymol, carvacrol and eugenol for Amblyomma sculptum control: evaluation of in vitro synergism and effectiveness under semi-field conditions

2021 ◽  
pp. 101816
Author(s):  
Letícia Vale ◽  
Luiza Gabriella Ferreira de Paula ◽  
Mirna Secchis Vieira ◽  
Susy das Graças Alecrim Alves ◽  
Nélio Roberto de Moraes Junior ◽  
...  
Keyword(s):  
Field Conditions ◽  
Control Evaluation

scholarly journals Controlling Brown Spot of Pear by a Synthetic Antimicrobial Peptide Under Field Conditions

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1816-1822 ◽  
Author(s):  
Mireia Puig ◽  
Concepció Moragrega ◽  
Lídia Ruz ◽  
Emilio Montesinos ◽  
Isidre Llorente
Keyword(s):  
Fungicidal Activity ◽  
Field Trials ◽  
Control Measures ◽  
Field Conditions ◽  
Brown Spot ◽  
Potted Plants ◽  
Detached Leaf ◽  
Brown Spot Disease ◽  
Pear Trees

Brown spot of pear, caused by Stemphylium vesicarium, is a fungal disease of increasing importance in several pear-growing areas of Europe. Disease control measures include the application of fungicides and sanitation methods. Antimicrobial peptides may be a complement or alternative to conventional fungicides used to manage brown spot disease. In a previous study, the synthetic peptide BP15 showed postinfection fungicidal activity against S. vesicarium in in vitro and detached-leaf assays. In the present study, the efficacy of BP15 (KKLFKKILKVL-NH2) in controlling brown spot of pear was evaluated under field conditions using potted plants and pear trees in orchards. In field trials, the treatments with BP15 or with the fungicide thiram were scheduled according to the infection risk predicted by the BSPcast model. Potted pear plants treated with BP15 showed a disease reduction of about 42 to 60% in five of seven trials. In three of four tree trials, the disease severity on shoots treated with BP15 was significantly lower than in the nontreated controls, with a mean efficacy of 38.2%. It was concluded that BP15 is a good candidate to be further developed as a fungicide for controlling brown spot of pear.

INFLUENCE OF TERBACIL ON MICROBIOTA IN SOIL AND CULTURES

1981 ◽  
Vol 61 (1) ◽  
pp. 11-17
Author(s):  
E.B. ROSLYCKY
Keyword(s):  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Field Conditions ◽  
In Vitro Growth ◽  
Soil Microbiota ◽  
Total Soil ◽  
Loam Soil ◽  
Bacteria And Fungi

Terbacil in concentrations up to 500 μg∙g−1 of sandy loam soil had little effect on populations of actinomycetes, bacteria, and fungi under laboratory and field conditions during a period of 5 mo. Concentrations up to 700 μg of terbacil∙mL−1 did not affect the in vitro growth of 111 strains of agriculturally important microorganisms, including effective, parasitic, and lysogenic rhizobia from seven cross-inoculation groups, pathogenic, attenuated, and saprophytic agrobacteria, azotobacters, and other bacteria, actinomycetes, and fungi. Terbacil inhibited the respiration of total soil microbiota, of bacteria, and of fungi at all concentrations tested. By contrast, it stimulated the respiration of actinomycetes at concentrations up to 500 μg∙mL−1 and partially inhibited it at 700 μg∙mL−1. Replication of bacterial and actinomycete isolates showed minimal inhibition by the extreme concentrations.

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