Abstract La Plata Basin is the second largest hydrographic system in South America but the most impacted by invasive species of molluscs in the continent. Paraguay is a land-surrounded South American country with scarce information about malacological fauna. To fill some of these gaps, a large field expedition was conducted to analyze the distribution of invasive freshwater bivalves in Paraguay. The field survey encompassed 41 sampling stations in seven Departments of Paraguay. The mussels were searched using bare hands and feet. All stations were georeferenced and some environmental parameters were measured. Results indicated the presence of three invasive species of freshwater bivalves in Paraguay: Corbicula fluminea, C. largillierti, and Limnoperna fortunei. The Asiatic clam Corbicula fluminea was the most widespread invasive species, covering main rivers and small tributaries in the four freshwater ecoregions of Paraguay. The two remaining invasive species were more restricted. Corbicula largillierti were found at the lower section of the Paraná River, and Limnoperna fortunei inhabits the main river canals of the Paraguay River and the lower section of the Paraná River. The invasive species were found in three protected areas of Paraguay and can represent a threat to the mostly unknown fauna of native mussels. The invasive bivalves are widespread in Paraguay. Mitigation measurements must be taken to avoid the spread of these species and more drawbacks over native fauna. continent landsurrounded land surrounded gaps 4 feet measured C restricted

Resumo A bacia do Plata é a segunda maior da América do Sul, mas a mais impactada pelas espécies invasoras de moluscos nesse continente. O Paraguai é uma país cercado por terra com pouca informação sobre a sua malacofauna. Com o objetivo de preencher algumas destas lacunas, uma expedição de campo foi organizada a fim de analisar a distribuição dos bivalves invasores no Paraguai. Foram realizadas 41 estações de coleta em sete departamentos do Paraguai. A busca pelos bivalves foi feita utilizando pés e mãos. Todos os pontos foram georreferenciados e algumas variáveis ambientais foram medidas. Os resultados indicam a presença de três espécies de bivalves invasores no Paraguai: Corbicula fluminea, C. largillierti e Limnoperna fortunei. O berbigão asiático Corbicula fluminea foi a espécie com a distribuição mais ampla, cobrindo os principais rios e tributários, em quatro ecoregiões de água doce do Paraguai. As outras duas espécies apresentaram uma distribuição mais restrita. Corbicula largillierti foi encontrado no Baixo rio Paraná, enquanto Limnoperna fortunei foi encontrado na calha principal do rio Paraguai e no Baixo rio Paraná. As espécies invasoras foram encontradas em três unidades de conservação e pode representar a ameaça para a pouco conhecida fauna de bivalves nativos do Paraguai. As espécies de bivalves invasores estão amplamente distribuídas no Paraguai. Medidas de mitigação são necessárias para evitar que estas espécies se dispersem ainda mais, provocando mais efeitos negativos sobre as espécies nativas. Sul continente malacofauna lacunas 4 mãos medidas C ampla tributários restrita Paraná nativas

Resumen:El objetivo del presente estudio fue evaluar la actividad fungicida de los extractos de tres especies de líquenes. De las especies Leptogium cyanescens, Physcia americana y Pyxine aff. cocoes fueron colectados extractos del talo liquénico en el año 2009, en áreas del Jardín Botánico de Cienfuegos, Cuba. La actividad fungicida fue evaluada en hongos fitopatógenos de papa;Rhizoctonia solani y Phytophthora nicotianae var parasitica. El estudio se realizó en el periodo comprendido del 2009-2011. Los compuestos se extrajeron con acetona, se concentraron por rotoevaporación, y se evaluaron a concentraciones de 0,01 y 0,07% en medio de cultivo agar papa dextrosa (PDA), para lo cual se preparó una solución madre al 5% en dimetisufóxido. Los extractos se clasificaron por su toxicidad como: tóxico, ligero y moderadamente tóxico e inocuo. El extracto de P. americana al 0,07% inhibió 100% a P. nicotianae, y frente a R. solani manifestó valores por encima de 50%. L. cyanescens solo mostró actividad fungicida en ambos fitopatógenos a la mayor concentración estudiada; resultados similares se obtuvieron con el extracto de P. aff. cocoes. Los extractos liquénicos se clasificaron como ligeramente tóxicos a la mayor concentración e inocuos a la menor concentración probada.

Abstract:The objective of this work was to evaluate the antifungal activity of the three lichens extracts. Extracts from Leptogium cyanescens, Physcia americanaand Pyxine aff. cocoes were collected from the lichens thallus in 2009 in areas fromo the Cienfuegos Botanic Garden, Cuba. The fungicide activity was evaluated against phytopathogens fungi of potato: Rhizoctonia solani andPhytophthora nicotianae var parasitica. The study was conducted from 2009 to 2011. The compounds were extracted with acetone, concentrated by rotoevaporation, and evaluated at concentrations of 0,01 and 0,07% in potato dextrose agar (PDA) culture medium; stock solution was made of 5% dimethilsufoxide. These extracts were classified by their toxicity as: toxic, slight and moderately toxic and harmless. The extracts from P. americana of 0,07% inhibited P. nicotianae 100%, and it showed values over 50% for R. solani. L. cyanescens only showed fungicide activity in both phytopathogens at the maximum concentration studied; similar results were obtained with the extract from P. aff. cocoes. The lichens extracts were classified as lightly toxic at the maximum concentration, and harmless at the minimum concentration.

The lichens are fungi that establish a symbiotic relation with one or various photosynthetic organisms (algae or cyanobacterium). In this relation the fungi (mycobiont) produce secondary metabolites with antibiotic activity. For this reason the fungicide effect of metabolites produced in culture media by the lichen's mycobiont Loxospora pustulata, above Rhizoctonia solani isolated from potato was verified. The mycobiont was cultivated in media potato dextrose agar (PDA) and it was fermented in potato broth by shaken culture. The metabolites were extracted with ethyl acetate. A solution in PDA at 0,01: 0.03: 0,07% w/v concentrations was prepared from the lichens extracts. R. solani discs were placed in the solution and the mycelial growth inhibition percentage was measured. The lichen extract showed 100% of inhibition of the R. solani mycelial growth to all concentrations.

Los líquenes son hongos que establecen una relación de simbiosis con uno o varios organismos fotosintéticos (algas o cianobacterias). En esta relación el hongo (micobionte) produce un determinado número de metabolitos secundarios con actividad antibiótica. De acuerdo a esta afirmación se propone: comprobar el efecto fungicida de los metabolitos secundarios producidos en medio de cultivo por el micobionte del liquen Loxospora pustulata, sobre Rhizoctonia solani aislado de papa. El micobionte se cultivó en medio agar papa dextrosa (PDA), posteriormente se fermentó en caldo de papa por cultivo agitado y los metabolitos se extrajeron con acetato de etilo. Se prepararon concentraciones de 0,01; 0,03; 0,07% p/v del extracto liquénico en PDA donde se sembraron discos de R. solani y se determinó el porcentaje de inhibición del crecimiento micelial. El extracto liquénico mostró 100% de inhibición del desarrollo de R. solani a las tres concentraciones.

The looking for new alternative to chemical control for integrated pest management to reduce the environmental impact has received attention internationally in last decades. Essentials oils have been using in pharmaceutical and cosmetic industry, recently they have become in an interesting possibility for pest and disease control. The fungicide activity of five monoterpens (menthol, thymol, camphor, citronellal and 1,8 cineol), commonly found in essentials oils was evaluated. The method of culture media poisoning was used with concentration of 0,5; 0,1 y 0,05% w/v. The inhibitory effect was evaluated on a Rhizoctonia solani isolate, pathogen which causes rizoctoniasis in potato crops. The inhibition percentage was calculated and the results were statistically analyzed. Thymol, menthol and citronellal showed 100% of inhibition at 0,5 and 0,1%. The monoterpens camphor and 1, 8 cineol showed lower values of inhibition percentage, but they will taking into account for future studies with a wider range of concentration.

En los últimos años la sociedad mundial ha priorizado los aspectos ambientales, y ha conducido un grupo de investigaciones hacia el descubrimiento de nuevas alternativas para el manejo integrado de plagas y enfermedades, con menos efectos negativos al ambiente. Los aceites esenciales, que hasta hace poco eran empleados solamente en la industria farmacéutica y cosmética, en la actualidad tienen gran importancia por su efecto en el control de plagas y enfermedades de las plantas. Basado en este criterio, se evaluó la actividad fungicida de cinco monoterpenos (mentol, timol, alcanfor, citronelal y 1,8 cineol) comúnmente encontrados en aceites esenciales. Se empleó el método de envenenamiento del medio de cultivo a concentraciones de 0,5; 0,1 y el 0,05% p/v para evaluar el efecto inhibitorio de cada uno sobre un aislado de Rhizoctonia solani, causante de la rizoctoniasis en papa. Se calculó el porcentaje de inhibición y los resultados se analizaron estadísticamente. Se obtuvo que timol, mentol y citronelal tuvieron el 100% de inhibición al 0,1 y el 0,5%; Por otra parte, alcanfor y 1,8 cineol mostraron resultados por debajo del 100%; pero se valorarán para posteriores estudios, donde el rango de concentración sea mayor.

The problems of stand establishment in rainfed wheat crops are related to seed quality. The aim of this work was to assess the bread-wheat-seed physical and physiological quality. The research was conducted during 2003 in the Seed Analysis Laboratory and greenhouse of the Colegio de Postgraduados, Montecillo, State of Mexico. Ten wheat cultivars of high vigor and industrial quality were utilized; in these seed size, hectoliter weight and the weight of 1000 seeds were determined. Three physiological quality tests were conducted, two in the laboratory (standard germination and coleoptile lenght), and one in a sand bed in the greenhouse, where the response to three planting depths (3, 6 and 9 cm) was measured as emergency rate, coleoptile length, plantlet length, and plantlet dry-weight. Data were analyzed as random blocks designs, and a subdivided plot design was used for the greenhouse data, as well as mean comparisons, analysis of correlations, and of genotype x environment interaction, where each planting depth was considered as an environment. Results indicated that the weight of 1000 seeds is an essential parameter for the selection of cultivars with the best physical and physiological seed quality. In the greenhouse test Tlaxcala F2000, Sokoll and Berkut cultivars had consistent emergency rates; Temporalera M87, Rebeca F2000 and Weebill 1 had a more consistent coleoptile length; and Berkut, Sokoll, Kambara 1 and Juchi F2000 had a more consistent plantlet length. Positive correlations were obtained between length of coleoptile and plantlet with the aerial part dry-weight, and between aerial part dry-weight and root dry-weight.

Los problemas con el establecimiento en las siembras de trigo en temporal están relacionados con la calidad de la semilla. El objetivo del trabajo fue evaluar la calidad física y fisiológica de la semilla de trigos harineros. Los trabajos se realizaron en 2003, en el Laboratorio de Análisis de Semillas y en el invernadero del Colegio de Postgraduados, Montecillo, Estado de México, México. Se utilizaron 10 variedades de trigo de buen vigor y calidad industrial, a las que se les determinó el tamaño de semilla, peso hectolítrico y peso de mil semillas. Se realizaron tres pruebas de calidad fisiológica, dos en laboratorio (germinación estándar y longitud de coleóptilo), y una en cama de arena en invernadero, donde se midió la respuesta a tres profundidades de siembra (3, 6 y 9 cm) a través de velocidad de emergencia, longitud de coleóptilo y de plántula, y peso seco de plántula. Los datos se analizaron con diseños de bloques al azar y los de invernadero con arreglo de parcelas subdivididas, y se realizaron comparación de medias, análisis de correlación y se analizó la interacción genotipo x ambiente considerando a las profundidades de siembra como ambientes diferentes. Los resultados indican que el peso de mil semillas es parámetro fundamental para seleccionar variedades con mejor calidad física y fisiológica. En la prueba de invernadero Tlaxcala F2000, Sokoll y Berkut, fueron estables en la velocidad de emergencia; Temporalera M87, Rebeca F2000 y Weebill 1 lo fueron para longitud de coleóptilo, y Berkut, Sokoll, Kambara 1 y Juchi F2000 para longitud de plántula. Se obtuvieron correlaciones positivas entre longitud de coleóptilo y parte aérea con peso seco de parte aérea, y entre peso seco de parte aérea con peso seco de raíz.

Toxocariasis is a parasitosis that affects little children, particularly those who like playing with the soil. With the objective of identifying the contamination of soils in parks and public areas in the City of Havana by toxocara sp, eggs. A crosswise descriptive study was performed from february to april, 1995 in which 50 g of soil was taken as a sample from each locality to be examined through a simple flotation-settling in conical cup procedure using a sodium nitrate solution (d=1,32) previously washed with Tween 80 detergent. It was found that 68.3% of the localities were polluted with Toxocara eggs, most of which were in embrionary phase, and that slight pollution prevailed. Some actions were recommended to reduce pollution of soils and human infection.

La toxocariasis es una parasitosis que afecta a los niños pequeños, en particular aquellos que juegan con la tierra. Con el objetivo de identificar la contaminación del suelo de parques y zonas públicas de Ciudad de La Habana por huevos de Toxocara sp., se realizó un estudio descriptivo de corte transversal de febrero a abril de 1995. De cada localidad se examinaron 50 g de suelo mediante un procedimiento de flotaciónsedimentación simple en copa cónica empleando solución de nitrato de sodio (d = 1,32) con previo lavado usando detergente Tween 80. Se encontró que el 68,3 % de las localidades estuvieron contaminadas con huevos de Toxocara los que en su mayoría estuvieron en su fase embrionaria, predominando las contaminaciones ligeras. Se recomendaron algunas medidas para reducir la contaminación del suelo y la infección del hombre.