Search results for "PEST"

Toxicity of several d-endotoxins of Bacillus thuringiensis against Helicoverpa armigera (Lepidoptera: Noctuidae) from Spain

2005

Abstract Toxicity and larval growth inhibition of 11 insecticidal proteins of Bacillus thuringiensis were evaluated against neonate larvae of Helicoverpa armigera, a major pest of important crops in Spain and other countries, by a whole-diet contamination method. The most active toxins were Cry1Ac4 and Cry2Aa1, with LC50 values of 3.5 and 6.3 μg/ml, respectively. At the concentrations tested, Cry1Ac4, Cry2Aa1, Cry9Ca, Cry1Fa1, Cry1Ab3, Cry2Ab2, Cry1Da, and Cry1Ja1, produced a significant growth inhibition, whereas Cry1Aa3, Cry1Ca2, and Cry1Ea had no effect.

Esterase isoenzymes and insecticide resistance in Frankliniella occidentalis populations from the south-east region of Spain.

2008

BACKGROUND:Frankliniella occidentalis (Pergande) is among the most important crop pests in the south-east region of Spain; its increasing resistance to insecticides constitutes a serious problem, and understanding the mechanisms involved is therefore of great interest. To this end, F. occidentalis populations, collected from the field at different locations in south-east Spain, were studied in terms of total esterase activity and esterase isoenzyme pattern. RESULTS: Individual thrips extracts were analysed by native polyacrylamide gel electrophoresis (PAGE) and stained for esterase activity with the model substrate α-naphthyl acetate. Significant correlations were found between resistance t…

Suppression ofBotrytis cinereacausing the grey mould disease of grape-vine by an aggressive mycoparasite,Pythium radiosum

1999

Pythium radiosum Paul has been found to be an aggressive mycoparasite of Botrytis cinerea which causes grey mould disease on the grape-vine. The mycoparasitic fungus enters the host mycelium, coagulates its protoplasm, empties its contents and finally comes out producing numerous ramifications and sexual structures. When the infected mycelium of B. cinerea is applied to the leaves of the grape-vine, the characteristic grey mould symptoms fail to appear. Since P. radiosum causes no harm to the grape-vine, it can be used as a biological control agent against B. cinerea. A brief account of the mycoparasite and its antagonism towards B. cinerea is discussed here.

An assessment method for the quantification of Daktulosphaira vitifoliae (Fitch) (Hem., Phylloxeridae) populations in the field

2003

:  Grape phylloxera is a plant parasite that has started to become a pest again in European viticulture in spite of the use of grafted rootstocks. Since the middle of the 1980s, there have been various reports of vine damage caused by phylloxera. It was shown that in some cases there is no direct correlation between the occurrence of phylloxera and vine damage. In this context, phytopathogenic microorganisms, especially fungi, are mentioned in literature. To investigate the possible interactions it is necessary to be able to assess phylloxera populations in the field, e.g. to correlate phylloxera abundance with the vigour of the vines. Because of the non-homogenous distribution of the grape…

Partial least squares-near infrared determination of pesticides in commercial formulations

2007

Abstract A solvent free, fast and environmentally friendly near infrared-based methodology (NIR) was developed for pesticide determination in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples and a multivariate calibration model (partial least squares, PLS) to determine the active principle concentration in commercial formulations. The PLS calibration set was built on using the spiked samples by mixing different amounts of pesticide standards and powdered samples. Buprofezin, Diuron and Daminozide were used as test analytes. Concentration of Buprofezin in the samples was calculated employing a 4-fact…

Application of capillary electrophoresis-mass spectrometry for determining organic food contaminants and residues.

2008

Food contamination continues to be a serious problem around the world. Surveillance of chemical contaminants in foods is important not only for public health but also because of the negative economic impact of contamination. From the analytical perspective, analysis of contaminants in food is an extremely challenging area. There is a wide variety of questions, ranging from the quantification of extremely low levels of individual components to the detailed assessment and evaluation of the analytical technique possibilities. This review considers the applications of CE coupled to MS detection (CE-MS) for the analysis of organic contaminants in food. Analytical information on sample concentrat…

Responses of Rhynchophorus ferrugineus adults to selected synthetic palm esters: electroantennographic studies and trap catches in an urban environme…

2010

BACKGROUND: The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, accidentally introduced into the European countries facing the Mediterranean basin, is becoming the most serious pest for ornamental palms in the urban environment. In the present work, tests were conducted on the electroantennogram (EAG) and behavioural responses of RPW adults to five selected synthetic palm esters, ethyl propionate, ethyl butyrate, ethyl isobutyrate, ethyl lactate and ethyl acetate, to assess the application of a mass trapping technique in an urban environment. RESULTS: In the laboratory, EAG bioassays on RPW adults with the synthetic palm esters showed: (1) positive dose-dependent responses; (2) di…

Race typing and molecular characterization of Xanthomonas campestris pv. campestris strains occurring in Italy

2015

Distinct Clones of Yersinia pestis Caused the Black Death

2010

From AD 1347 to AD 1353, the Black Death killed tens of millions of people in Europe, leaving misery and devastation in its wake, with successive epidemics ravaging the continent until the 18th century. The etiology of this disease has remained highly controversial, ranging from claims based on genetics and the historical descriptions of symptoms that it was caused by Yersinia pestis to conclusions that it must have been caused by other pathogens. It has also been disputed whether plague had the same etiology in northern and southern Europe. Here we identified DNA and protein signatures specific for Y. pestis in human skeletons from mass graves in northern, central and southern Europe that …

Determination at low ppm levels of dithiocarbamate residues in foodstuff by vapour phase-liquid phase microextraction-infrared spectroscopy

2010

Abstract A methodology based on the vapour phase (VP) generation of carbon disulphide from non-volatile dithiocarbamate compounds has been developed for determination of pesticide residues in foodstuff at low ppm levels. The method involves a selective reaction combined with liquid phase microextraction (LPME) and transmission infrared measurements. The use of a home made transmission cell improved the detection limits (LOD) compared to the use of attenuated total reflectance measurements by a factor of approximately 80. Using the most appropriate experimental conditions for the CS2 generation and LPME preconcentration, the precision of the methodology, expressed as the relative standard de…