Galvao J.A.H.,Sao Paulo State University |
Bettiol W.,Embrapa Meio Ambiente
Tropical Plant Pathology | Year: 2014
Coffee leaf rust is the main disease of coffee and its causal agent is naturally hyperparasited by Lecanicillium lecanii, indicating its potential for biocontrol. Ultraviolet-B (UV-B) radiation is an important factor that interferes on application of biocontrol agents, and Lecanicillium can be affected by UV-B. The objective of this work was to evaluate the effects of UV-B on Lecanicillium isolates and on its capacity to colonize rust lesions. There were variations among Lecanicillium strains in sensitivity to UV-B radiation, causing inactivation and delayed spore germination. The most tolerant strain (CCMA-1143) had LD50=1.63 kJ/m2 of UV-B. The incidence and colonization of Lecanicillium on coffee leaf rust lesions were infuenced by the dose of UV-B radiation, and were increased when the isolate CCMA-1143 was sprayed on rust lesions. The effects of UV-B should be considered on effcacy studies for the development of biopesticides. © 2014, Sociedade Brasileira de Fitopatologia. All rights reserved.
Machado M.A.C.F.,Federal University of Sao Carlos |
Bettiol W.,Embrapa Meio Ambiente
Pesquisa Agropecuaria Brasileira | Year: 2010
The objective of this study was to compare a population of phylloplane yeasts in lilies cultivated in a conventional cultivation system to other lilies in an integrated system, as well as to evaluate the antagonism of Sporidiobolus pararoseus to Botrytis cinerea. The yeast community was estimated by the spore-fall method in the lower, middle and upper thirds of the plants, as well as in the abaxial and adaxial leaf surfaces. The yeast population was high on the leaf discs of the plants from the integrated system, and it was higher on the adaxial surface and on leaves from the middle third of the plants. To evaluate yeast antagonism, concentrations of 10 5, 10 6 and 10 7 cells mL -1 were sprayed on the leaf discs in three inoculation times: 24 hours before; simultaneously; and 24 hours after inoculation with B. cinerea at a concentration of 10 4 spores mL -1. The incidence and percentage of disc tissue area colonized and of B. cinerea sporulation were evaluated through a category scale, starting from the fourth day after the inoculation. All yeast concentrations reduced B. cinerea sporulation on the leaf discs in comparison to the control, and the yeast concentration of 10 7 cells mL -1 was the most effective.
Procopio A.R.,Embrapa Meio Ambiente
Genetics and molecular research : GMR | Year: 2012
The herbicide propanil has long been used in rice production in southern Brazil. Bacteria isolated from contaminated soils in Massaranduba, Santa Catarina, Brazil, were found to be able to grow in the presence of propanil, using this compound as a carbon source. Thirty strains were identified as Pseudomonas (86.7%), Serratia (10.0%), and Acinetobacter (3.3%), based on phylogenetic analysis of 16S rDNA. Little genetic diversity was found within species, more than 95% homology, suggesting that there is selective pressure to metabolize propanil in the microbial community. Two strains of Pseudomonas (AF7 and AF1) were selected in bioreactor containing chemotactic growth medium, with the highest degradation activity of propanil exhibited by strain AF7, followed by AF1 (60 and 40%, respectively). These strains when encapsulated in alginate exhibited a high survival rate and were able to colonize the rice root surfaces. Inoculation with Pseudomonas strains AF7 and AF1 significantly improved the plant height of rice. Most of the Pseudomonas strains produced indoleacetic acid, soluble mineral phosphate, and fixed nitrogen. These bacterial strains could potentially be used for the bioremediation of propanil-contaminated soils and the promotion of plant growth.
Ovalle A.R.C.,State University of Norte Fluminense |
Silva C.F.,State University of Norte Fluminense |
Rezende C.E.,State University of Norte Fluminense |
Gatts C.E.N.,State University of Norte Fluminense |
And 2 more authors.
Journal of Hydrology | Year: 2013
The Paraíba do Sul watershed is an important hydrological resource for southeastern Brazil, that has undergone extensive land use changes related to industrial, agricultural and urban activities. Over 11years, between 1997 and 2007, a long-term study was conducted to evaluate hydrochemical variation in the basin outlet through estimations of annual fluxes and identification of their controlling factors. River water was classified as Na-HCO3, with TDS ranging from 32 to 132mgL-1. Variation between seasons was found: cations, total alkalinity, electrical conductivity, dissolved oxygen, nitrate and chlorophyll "a" had increased values the during low discharge period, while concentrations of DOC, ammonium, nitrite, phosphate and SPM had increased values during the high discharge period. Chloride, sulfate, silica and pH showed no clear relationship with discharge. These patterns also were correlated with hydrological flow paths originating from different sources. Wavelet decomposition was used to characterize precipitation anomalies largely associated both with long-term climate factors (i.e. ENSO) and short-term climate responses from the two discharge periods that were studied. Distinct responses of fluvial hydrochemistry were observed including ENSO-induced fluctuation to be particularly strong for DOC, with annual flux varying approximately 60% around measured median value. © 2013.
De Assis M.C.,Embrapa Meio Ambiente
Rodriguesia | Year: 2012
Alstroemeriaceae comprises perennial herbs that are erect or twining and rhizomatous. The leaves are generally resupinate. They are found in a wide range of habitats including cloud forests, swamps and desert areas. The family is represented at South of Brazil by 2 genus: Alstroemeria L. and Bomarea Mirb. Alstroemeria included 9 species: Alstroemeria albescens M.C.Assis, A. amabilis M.C.Assis, A. apertiflora Baker, A. cunha Vell., A. inodora Herb., A. isabelleana Herb., A. malmeana Kraenzl., A. psittacina Lehm., A. sellowiana Seub. ex Schenk. Bomarea included just one specie, B. edulis (Tussac) Herb. New synonym, key to genera and species, descriptions, illustrations and comments are presented.