Search results for "PEST"

Esterase inhibition by synergists in the western flower thrips Frankliniella occidentalis.

2010

BACKGROUND: Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is among the most important crop pests in the south-eastern region of Spain. Its increasing resistance to insecticides constitutes a serious problem, and understanding the mechanisms involved is therefore of great interest. Use of synergists to inhibit the enzymes involved in insecticide detoxification is widely used to determine their responsibility for insecticide resistance. However, they do not always act as intended or expected, and caution must be exercised when interpreting synergist results. RESULTS: Laboratory-selected strains of WFT were used to analyse the effects of the synergists piperonyl butoxide …

Sedimentological implications of an unusual form of the trace fossil Rhizocorallium from the Lower Muschelkalk (Middle Triassic), S. Poland

2011

Specimens of the trace fossil Rhizocorallium isp. with retrusive limbs occur in 10–20-cm-thick composite beds: the bottom layers contain abundant Planolites and Thalassinoides trace fossils, and the top layers are built of horizontally bedded pelitic limestone and contain less bioturbational structures. The first specimens of Rhizocorallium isp. occur just 2–3 cm above the lower surfaces of the top layers. The horizontal protrusive sections are 1 cm high and 1 cm wide. At some sites, the horizontal tunnels end, and the limbs become first obliquely retrusive (45°) at a distance of 1.5–2.5 cm, and then vertically retrusive at a distance of 4–6 cm, or at once vertically retrusive at a similar …

Crotonic acid as a bioactive factor in carrot seeds (Daucus carota L.)

2004

Water extracts from the carrot seed (Daucus carota L.) var. Perfekcja exhibit plant growth inhibitory properties against cress, cucumber, onion and carrot in a dose-dependant manner. This property results from the action of low-and high-molecular components of the extract. The low-molecular component was identified as crotonic acid ((E)-2-butenoic acid). Its presence was also confirmed in other late varieties of carrot. The determined strong herbicidal properties of crotonic acid and its availability after release to soil combined with its high level in seeds suggest that it might be considered as an allelopathic and autotoxic factor in the seeds.

Experimental Study on Diflubenzuron: Degradation in Freshwater and Bioconcentration in Mosquitofish Following Chronic Exposure

2013

ISSN: 2152-2197 ; ESSN: 2152-2219. Editeur commercial : Scientific Research Publishing; International audience; Diflubenzuron (DFB, trade name dimilin® 25 WP) is a chitin synthesis inhibitor widely used against forest insect pests in Algeria. Prior to implementation of these products as chemical agents for mosquito control, knowledge on their potential effects on non-target organisms and its behaviour in water are needed. Therefore, the present study was focused on DFB and aimed to use an HPLC procedure developed previously in order to obtain information on its degradation in freshwater and its bioconcentration in adult females of the fish Gambusia affinis (Cyprinodondiformes, Poeciliidae),…

Using semi-permeable membrane devices as passive samplers

2007

Abstract We discuss the present state of, and future developments in, using semi-permeable membrane devices (SPMDs) for environmental monitoring of organic pollutants. SPMDs allow the determination of time-weighted average concentrations of bioavailable pollutants in the sampled media, reducing significantly the costs of analysis compared with active samplers. We summarize developments in SPMDs, including simplified devices and devices modified by incorporating solvents other than triolein, and applications. We review contaminants (e.g., organotin compounds, polycyclic musk, triclosan, petroleum biomarkers, nitrated PAHs, polychlorinated naphthalenes and a wide range of pesticides sampled i…

Efficiency of the microwave-assisted extraction of hydrocarbons and pesticides from sediments

1997

Abstract A mixture of toluene and water is proposed for the microwave-assisted extraction of organic pollutants, hydrocarbons and pesticides, from marine sediments. The effect of experimental conditions, such as microwave power and irradiation time, on the extraction of linear, unresolved and polycyclic aromatic hydrocarbons as well as PCBs and DDTs has been evaluated using real marine sediment samples. Values found by Soxhlet and ultrasonic extraction were employed to evaluate the efficiency of the microwave-assisted extraction. Analytical determinations were carried out by gas chromatography using FID, ECD and MS detectors. For 2 g of a dry sediment, an extraction time of 6 min with 10 ml…

In situ Pesticide Detection in Food Processing by Microwave Transduction Combined with Molecularly Imprinted Polymers

2016

International audience; Since 2005, the microwave transduction coupled with a sensitive material is devoted to gas detection. In this work, we demonstrate the possibility to detect liquid pollutant (pesticide, fungicide) for food-processing industry. The principle is based on the interaction of the pollutant with a sensitive material within a microwave structure. The sensor is submitted to an electromagnetic excitation in wideband frequencies (GHz) and presents a quantitative response to liquid pollutant expositions at low concentration. The retained sensitive material is a molecularly imprinted polymer (MIP) specific to the pesticide targeted in a model wine. The coupling with this materia…

Acute toxicity of organochlorined pesticides to the European eel,Anguilla anguilla: The dependency on exposure time and temperature

1987

Molecular Clustering of Phenylurea Herbicides: Comparison with Sulphonylureas, Pesticides and Persistent Organic Pollutants

2014

Chromatographic retention times of phenylurea herbicides are modelled by structure–property relationships. Properties are hydration free energy and dipole. Bioplastic evolution is an evolutionary perspective conjugating the effect of acquired characters and relations that emerge among evolutionary indeterminacy, morphological determination and natural selection principles. Classification algorithms are proposed based on information entropy and production. Phenylureas are classified by Cl2, O2 and N2 presence; their different behaviour depends on the number of Cl atoms. When applying procedures to moderate-sized sets, excessive results appear compatible with data and suffer a combinatorial e…

Emerging Contaminants

2015

Brominated flame retardants (BFRs), compounds formed during food processing, mycotoxins, perfluoroalkyl substances (PFASs), pesticides, phycotoxins, polycyclic aromatic hydrocarbons (PAHs), and veterinary drugs are considered environmental emerging contaminants of particular concern. This chapter reviews the most important groups of emerging contaminants as well as the analytical platforms based on mass spectrometry (MS) developed to determine their presence in food. MS instruments utilize many different types of mass analyzers to improve selectivity and also confidence in assigning the identity of these emerging pollutants. Current analytical approaches are discussed together with the majo…