RESUMO
The acaricidal effects of 55 strains of Metarhizium anisopliae (Metschnikoff) Sorokin, 1883 (Hypocreales: Clavicipitaceae) isolated from paddocks of cattle farms were evaluated in two Rhipicephalus microplus (Canestrini 1887) (Ixodida: Ixodidae) populations, of which one was multi-resistant and one was susceptible to chemical acaricides. Percentage mortality and reproductive efficiency indices in R. microplus were evaluated by adult immersion tests at a dose of 1 × 108 conidia/mL for each fungal strain. Some strains were selected to calculate lethal concentrations to kill 50% (LC50 ) and 99% (LC99 ) of engorged ticks. Strains MaV22, MaV26 and MaV55 induced 100% mortality in R. microplus on day 14. Strains MaV05, MaV09 and MaV22 caused mortality of >90% from day 12 onward in both tick populations. The most effective acaricidal fungal strain, MaV55, inhibited egg laying by 54.86 and 55.86% in acaricide-resistant and -susceptible R. microplus populations, respectively. None of the fungal strains had statistically significant effects on larval hatching. In conclusion, nine strains of M. anisopliae demonstrated high acaricidal effects against R. microplus and reduced its egg laying. No differences in acaricidal effects were observed between the two populations of ticks tested.
Assuntos
Doenças dos Bovinos/prevenção & controle , Metarhizium/fisiologia , Controle Biológico de Vetores , Rhipicephalus/microbiologia , Infestações por Carrapato/veterinária , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Feminino , Larva/crescimento & desenvolvimento , Larva/microbiologia , Masculino , Metarhizium/genética , México , Rhipicephalus/crescimento & desenvolvimento , Rhipicephalus/fisiologia , Controle de Ácaros e Carrapatos , Infestações por Carrapato/parasitologia , Infestações por Carrapato/prevenção & controleRESUMO
El objetivo de este artículo fue analizar datos meteorológicos para identificar el comportamiento de variables físicas de relevancia y definir el clima de la región y el microclima de Yopal, Casanare. Se estudiaron los registros de las variables climáticas en una serie de tiempo de treinta años en la estación meteorológica del aeropuerto de Yopal, los cuales fueron suministrados por el Instituto de Estudios Ambientales y Meteorológicos (Ideam). Luego se llevó a cabo una tipificación climática basada en las clasificaciones más utilizadas por la comunidad científica, como son Thornthwaite, De Martone y Koppen, con el propósito de situar climáticamente la región de estudio. Por último, se analizaron las dos variables físicas más importantes en cuanto al comportamiento del microclima del lugar respecto al crecimiento de la vegetación, por sus procesos de evapotranspiración y uso del recurso hídrico.
The purpose of this article was to analyze meteorological data to identify the behavior of relevant physical variables and to define the regional climate and microclimate of Yopal, Casanare. The records of climatic variables in a time period of thirty years at the Yopal airport weather station, supplied by the Institute of Environmental and Meteorological Studies (Ideam), were studied. Then, a climatic classification was performed, based on the most used classifications by the scientific community, such as Thornthwaite, De Martone and Koppen, in order to climatically locate the region under study. Finally, the two most important physical variables were analyzed, in terms of behavior of the microclimate of the site regarding the growth of vegetation, by its processes of evapotranspiration and water use.
O objetivo deste artigo foi analisar dados meteorológicos para identificar o comportamento de variáveis físicas de relevância e definir o clima da região e o microclima de Yopal, Casanare. Estudaram-se os registros das variáveis climáticas em uma série de tempo de trinta anos na estação meteorológica do aeroporto de Yopal, os quais foram fornecidos pelo Instituto de Estudos Ambientais e Meteorológicos (Ideam). Depois foi realizada uma tipificação climática baseada nas classificações mais utilizadas pela comunidade científica, como é Thornthwaite, De Martone e Koppen, com o propósito de situar climaticamente a região de estudo. Por último, analisaram-se as duas variáveis físicas mais importantes, em quanto ao comportamento do microclima do lugar com relação ao crescimento da vegetação, por seus processos de evapotranspiração e uso do recurso hídrico.
RESUMO
El objetivo fue comparar, en cuanto a productividad en materia seca y captura de carbono, entre un sistema silvopastoril y un sistema tradicional en cinco fincas ganaderas de piedemonte del departamento de Casanare. En el lote experimental de cada finca se sembró una mezcla de cuatro especies de pastos, de los cuales Brachiaria brizantha fue la especie que tuvo un desarrollo exitoso en las cinco fincas, y con la cual se analizó su productividad en materia seca y captura de carbono. A los cinco meses después de la renovación de pastos en los lotes experimentales se obtuvo una productividad en materia seca entre 6,3 y 14,9 tMS/ha, y encaptura de carbono entre 2,7 y 6,4 tCOT/ha; mientras que en los lotes tradicionales estuvo entre 4 y 5 tMS/ha, y en captura de carbono entre 1,7 y 2,9 tCOT/ha. A los 20 meses en los lotes experimentales se obtuvo una productividad en materia seca entre 12 y 13,7 tMS/ha, y en captura de carbono entre 4,1 y 4,5 tCOT/ha; mientras que en los lotes tradicionales estuvo entre 4,4 y 6,5 tMS/ha, y en captura de carbono entre 1,4 y 2,1 tCOT/ha. Esto indica que la renovación de praderas con pastos adecuados y el pastoreo de rotación favorecen la producción en materia seca y la captura de carbono...
The goal was to compare, in terms of dry matter productivity and carbon sequestration, asilvopastoral system with a traditional system in five foothill cattle farms in the Departmentof Casanare. A mixture of four species of grass was planted in the experimental plot of eachfarm, of which Brachiaria brizantha was the species that had a successful development in thefive farms, and whose dry matter and carbon sequestration productivity was analyzed. Fivemonths after pasture renovation in the experimental lots, a dry matter productivity between6.3 and 14.9 tMS/ha and carbon sequestration productivity between 2.7 and 6.4 tCOT/ha were obtained; in traditional lots, dry matter productivity was between 4 and 5 tMS/ha,while carbon sequestration productivity was between 1.7 and 2.9 tCOT/ha. At 20 months, dry matter productivity between 12 and 13.7 tMS/ha, and carbon sequestration productivitybetween 4.1 and 4.5 tCOT/ha were obtained in experimental lots, while in traditionallots, dry matter productivity was between 4.4 and 6.5 tMS/ha, while carbon sequestrationproductivity was between 1.4 and 2.1 tCOT/ha. This indicates that renewal of grasslandswith suitable pastures and rotational grazing favor dry matter and carbon sequestration production...
O objetivo foi comparar, com respeito à produtividade em matéria seca e captura de carbono,um sistema silvipastoril e um sistema tradicional em cinco fazendas de criação de gado nodepartamento de Casanare. No lote experimental de cada fazenda plantou-se uma misturade quatro espécies de pastos, dos quais Brachiaria brizantha foi a espécie que teve um desenvolvimentobem-sucedido nas cinco fazendas, e com a qual analisou-se sua produtividadeem matéria seca e captura de carbono. Cinco meses depois da renovação de pastos nos lotesexperimentais obteve-se uma produtividade em matéria seca entre 6,3 e 14,9 tMS/ha, e umacaptura de carbono entre 2,7 e 6,4 tCOT/ha; enquanto que nos lotes tradicionais esteveentre 4 e 5 tMS/ha, e uma captura de carbono entre 1,7 e 2,9 tCOT/ha. Aos 20 meses noslotes experimentais obteve-se uma produtividade em matéria seca entre 12 e 13,7 tMS/ha, eem captura de carbono entre 4,1 e 4,5 tCOT/ha; enquanto que nos lotes tradicionais esteveentre 4,4 e 6,5 tMS/ha, e uma captura de carbono entre 1,4 e 2,1 tCOT/ha. Isto indica quea renovação de pastos com variedades adequadas e o pastoreio de rotação favorecem a produçãode matéria seca e a captura de carbono...
Assuntos
Humanos , Carbono , Eficiência , PoaRESUMO
Grassland-based production systems use â¼26% of land surface on earth. However, there are no evaluations of these systems as a source of antibiotic pollution. This study was conducted to evaluate the presence, diversity, and distribution of tetracycline resistance genes in the grasslands of the Colombian Andes, where administration of antibiotics to animals is limited to treat disease and growth promoters are not included in animals' diet. Animal (ruminal fluid and feces) and environmental (soil and water) samples were collected from different dairy cattle farms and evaluated by PCR for the genes tet(M), tet(O), tetB(P), tet(Q), tet(W), tet(S), tet(T), otr(A), which encode ribosomal protection proteins (RPPs), and the genes tet(A), tet(B), tet(D), tet(H), tet(J), and tet(Z), encoding efflux pumps. A wide distribution and high frequency for genes tet(W) and tet(Q) were found in both sample types. Genes tet(O) and tetB(P), detected in high frequencies in feces, were detected in low frequencies or not detected at all in the environment. Other genes encoding RPPs, such as tet(M), tet(S), and tet(T), were detected at very low frequencies and restricted distributions. Genes encoding efflux pumps were not common in this region, and only two of them, tet(B) and tet(Z), were detected. DGGE-PCR followed by comparative sequence analysis of tet(W) and tet(Q) showed that the sequences detected in animals did not differ from those coming from soil and water. Finally, the farms sampled in this study showed more than 50% similarity in relation to the tet genes detected. In conclusion, there was a remarkable presence of tet genes in these production systems and, although not all genes detected in animal reservoirs were detected in the environment, there is a predominant distribution of tet(W) and tet(Q) in both animal and environmental reservoirs. Sequence similarity analysis suggests the transmission of these genes from animals to the environment.