Efficiency of rice seed treatment with fungicides for controlling Helminthosporium oryzae

Com o objetivo de determinar a eficiência de fungicidas em tratamento de sementes de arroz (Oryza sativa L.), para controle de H. oryzae, amostra de sementes da cultivar IAC 47 com 46% de infecção, por esse fungo, foi tratada com os fungicidas abaixo relacionados nas seguintes dosagens de i.a., por kg de sementes: Thiram 70 P5 1750 mg; Captan 50 PM 1500 mg; Guazatine + Imazalil (30 + 2) L 0,64 ml; Iprodione 50 PM 1000 mg; Iprodione + Thiram (20 PM + 60 P5) 2000 mg e Imazalil 2,5 P5 87,5 mg. Com as sementes tratadas foi conduzido experimento de campo no município de Paulínia, SP, seguindo o delineamento experimental de blocos casualizados com 4 repetições. Os resultados mostraram que a maioria dos produtos reduziu significativamente o nível de infecção de sementes, sobressaindo em eficiência os fungicidas Guazatine + Imazalil, Iprodione e Iprodione + Thiram. Com relação a emergência e produção não foram observadas diferenças entre os tratamentos. Entretanto, análise efetuada com os parâmetros avaliados mostrou correlação significativa entre infecção de sementes e emergência e entre infecção e produção o que evidenciou a influência do tratamento de sementes sobre esses parâmetros. In order to verify efficiency of fungicides in rice seed treatment for controlling Helminthosporium oryzae, a seed sample of rice from cultivar IAC 47 with 46% fungus infection was treated with several fungicides and tested for health by the blotter method. The following products were used: thiram 70 dust, 1750 mg a.i./kg of seeds; captan 50 WP 1500 mg; guazatine + imazalil (30 + 2) L 0.64 ml; iprodione 50 WP 1000 mg; iprodione + thiram (20 WP + 60 dust) 2000 mg; imazalil 2,5 dust 87,5 mg. Most of the fungicides significantly reduced H. oryzae seed infection. The most efficient were: guazatine + imazalil, iprodione and iprodione + thiram. A field experiment was carried out in the 1983/84 growing season of with treated seeds in randomized plots with four replications. Although differences between treatments were not significant for emergence and production, negative correlation obtained for seed infection x emergence as well as for seed infection x production, showed influence of seed treatment on these parameters.

Ventajas y riesgos del uso de pastas dentales con nanotecnologías

El presente artículo de actualización analiza las ventajas y riesgos del uso de nanopartículas en pastas dentales. La nanotecnología puede mejorar sus propiedades ayudando al proceso de remineralización del diente, controlar el crecimiento bacteriano o proporcionar minerales para mejorar el control del pH. Con este fin se han agregado: nanohidroxiapatita, nanocalcio, fosfato de calcio, trimetafosfato de sodio, nanopartículas de plata, quitosán, entre otras. Por otro lado, se han descripto algunos efectos nocivos de estas nanotecnologías, lo que nos motiva a intensificar su estudio. Conclusiones: La nano-odontología ha otorgado nuevas herramientas para la atención preventiva de la salud. La toxicidad oral para los nanodentífricos es baja, pero algunos pueden llegar al intestino, y a través de él a la circulación sanguínea y causar disturbios sistémicos. Es necesario profundizar las investigaciones en estos materiales, a fin de mejorar sus efectos beneficiosos, e identificar y eliminar sus riesgo

Mycotoxins And Fungi In Wheat Stored In Elevators In The State Of Rio Grande Do Sul, Brazil.

Samples of wheat harvested from 1988 to 1990 and stored in elevators in the south of Brazil (12 Brazilian, 4 Argentinian and 2 Uruguayan) were analysed in 1990 for 14 mycotoxins: deoxynivalenol (DON), nivalenol, diacetoxyscirpenol (DAS), T-2 and HT-2 toxins, T-2 triol, T-2 tetraol, aflatoxins B1, B2, G1, G2, ochratoxin A (OCHRA A), zearalenone and sterigmatocystin. One sample (1988 harvest) was contaminated with OCHRA A (0.04 microgram/g) and three other samples (1990 harvest) were contaminated with DON (0.40 microgram/g), DAS (0.30 microgram/g), T-2 (two samples, 0.35 and 0.36 gamma g/g) and T-2 tetraol (1.68 micrograms/g). Fusarium graminearum Schwabe was found in the 1990 samples with a relative incidence ranging from 1 to 22% and predominated in Argentinian and Uruguayan wheat (1990 harvest). Fusarium dimerum Penzig (8-75%) was the main Fusarium sp. in Brazilian wheat from the 1990 harvest.12683-

Mycotoxins And Fungi In Wheat Harvested During 1990 In Test Plots In The State Of São Paulo, Brazil.

Wheat from two cultivars with contrasting characteristics were harvested in ten experimental plots located in wheat producing areas of the State of São Paulo, Brazil. The samples (10 of each cultivar) were analyzed by a gas-chromatographic method for deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), toxins T-2 (T-2) and HT-2, T-2 tetraol, T-2 triol, and by a thin-layer chromatographic method for zearalenone (ZEN), aflatoxins B1, B2, G1, G2, ochratoxin A and sterigmatocystin. No mycotoxins were detected in 13 samples. DON was found in four samples (0.47-0.59 microgram/g), NIV in three samples (0.16-0.40 microgram/g), T-2 in two samples (0.40, 0.80 microgram/g), DAS in one sample (0.60 microgram/g), and ZEN in three samples (0.04-0.21 microgram/g). The wheat samples were also examined for the incidence of fungi. Alternaria, Drechslera, Epicoccum and Cladosporium were the prevailing genera. Among the Fusarium spp., F. semitectum was present in 19 samples and F. moniliforme in 18 samples. No F. graminearum was isolated in the samples.131185-9