Leucothecium emdenii: A novel larvicidal fungus against mosquito larvae.
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Aedes↗
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Results for “Pest Control”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
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Research priorities for managing the transmission of vector-borne disease.
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Animals↗
The role of science in pesticide management. Report by the rapporteur.
The workshop program reviewed "the existing situation" on the first day, "background to existing divergency in pesticide regulation" and "pest control in the future" on the second day, and "analysis of the role of Science in enhancing regulatory wisdom" on the last day. This report reviews the topics in the order in which they affected the underlying question posed to the workshop--"how is it that the same pesticide can be regulated differently in different countries when the data are the same?" In this regard, the key presentations at the workshop were those which described results of international reviews of the ways in which countries regulated pesticides and how different countries could reach different decisions based on the same scientific information base.
Animals↗
Regulatory oversight of biochemical pesticides by the U.S. Environmental Protection Agency: health effects considerations.
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) enables the Office of Pesticide Programs (OPP) of the U.S. Environmental Protection Agency to ensure that pesticide use in commerce will not result in unreasonable adverse effects to humans and the environment. Currently, two classes of pesticides are recognized: conventional chemical pesticides and biological pesticides. The latter group is divided into biochemical and microbial pesticides. The recent resurgence of biochemical pesticides as effective pest control agents has increased the number of applications for experimental use permits and for product registration. The fundamental information and data necessary to evaluate such products by the Health Effects Division (HED) of OPP are discussed, as well as the criteria for the classification of a pesticide as a biochemical versus a conventional chemical pesticide. In accordance with the Agency's effort to encourage the development of pesticides less toxic to humans and the environment, the scientific basis for providing future regulatory relief and reduced data requirements for biochemical pesticides is discussed.
Animals↗
Primary infection of insect tracheae by Autographa californica M nuclear polyhedrosis virus.
Previously we found that Autographa californica M nuclear polyhedrosis virus infections initiated in the midguts of insect hosts are disseminated within the hosts via tracheae, elements composing the insect respiratory system. Herein we report that infection of tracheae also can be initiated directly via the spiracles, exterior openings of the tracheal system to the atmosphere. Infections were initiated both by direct application of viral inoculum to the spiracles and by aerosol. Infections established by both these methods appeared to advance much more rapidly than infections established by the oral route, and a host highly refractory to infection orally was easily susceptible to direct tracheal infection. These findings are important for continuing efforts to improve the use of baculoviruses as pest control agents; they also establish the possibility that direct tracheal infection via aerosol may facilitate horizontal transmission of baculoviruses during natural epizootics.
Animals↗
Environmental fate of methyl bromide as a soil fumigant.
The great variation among results of recent experiments measuring the total emission of MeBr from fields implies that many factors influence MeBr transport and transformation in the soil-water-air system and its ultimate loss from the soil surface. It has been demonstrated that variables related to application methods (e.g., injection depth, use and type of surface tarp), soil properties (e.g., water content, bulk density, soil organic matter), and climatic conditions (e.g.. air temperature, wind speed, barometric pressure) have pronounced effects on MeBr volatilization following soil injection. The following conclusions can be drawn from this experimental information. Tarping consistently, increased the residence time and concentration of MeBr residing in the soil. Prolonged retention of MeBr in the soil resulted in more extensive degradation and reduced cumulative emissions. Research indicates that the polyethylene film typically used for the surface cover is relatively permeable to MeBr and allows significant emissions compared to virtually impermeable plastic films. This effect is more pronounced during periods of high temperature. Soil type, soil water content, and bulk density are important factors affecting MeBr transport and transformation in soil, which ultimately affect volatilization. The total volatilization from a soil with high organic matter content may be drastically reduced relative to that from a low organic matter soil. Amendment of the surface soil with organic matter or nucleophilic compounds that promote increased degradation may offer another method for reducing volatilization. MeBr volatilization may also be decreased by increasing soil water content and bulk density, mainly because of the reduced gas-phase diffusion resulting from reduced soil air-filled porosity. To minimize volatilization, MeBr should be applied during periods of cool temperature, injected relatively deep in organic-rich, moist soil, and the soil surface packed and tarped immediately after the application. Depending on site-specific conditions, a new high-barrier plastic should be used. Injecting MeBr during periods of warm temperature, at a shallow depth in dry, loose soil without the use of low-permeability plastic barriers, will likely result in maximum volatilization rates and therefore should be discouraged. Before adopting any new emission reduction technology, the pest control characteristics of the new methodology should be assessed under soil and environmental conditions typical of the region to optimize efficacy while minimizing environmental contamination. There is considerable current scientific evidence indicating that eliminating MeBr use for soil fumigation may not have a significant impact on stratospheric ozone depletion. Management practices can and have been developed that essentially eliminate atmospheric emissions of MeBr and other fumigant compounds following soil application. Some scientists have suggested that there are natural buffers and various unknown sources of MeBr that make it impossible to ascertain that eliminating soil fumigation with MeBr will significantly improve stratospheric ozone levels. It is quite certain, however, that the phase-out will make it much more difficult for growers to economically provide an adequate and healthful food supply in the U.S. and elsewhere in the world. As the phase-out date approaches, there remains a great need for information about MeBr and stratospheric ozone depletion. Stratospheric ozone must be protected, but recent experiments suggest that it can be protected while still allowing MeBr to be used for soil fumigation. A new approach may be warranted in which state and federal regulations recognize that every chemical is a potential environmental contaminant, depending on the properties of the chemical and the environmental conditions prevailing following its application. Ideally, regulations should incorporate incentives to develop technology that minimizes the likelihood that a chemical becomes an environmental and/or public health problem. Rather than instituting an irrevocable ban, allowing for a suspension of chemical use until the appropriate technology is developed to control the undesirable characteristic(s) of the chemical use would provide much more flexibility to growers and may enhance environmental protection by adopting a proactive approach in which growers, chemical manufacturers, regulators, and the public can have confidence.
Adsorption↗
Cell signalling during sea urchin development: a model for assessing toxicity of environmental contaminants.
The early development of sea urchins has been thoroughly studied since the beginning of the 20th century thanks to the particular features of the model involving cell signalling, making it easy to follow the complex cell-to-cell interactions that lead to development. In this chapter, the prominent role of cell-to-cell communication in developmental events is discussed, as well as the role of intracellular ion changes that are in turn regulated by signal molecules belonging to the cholinergic system. The results seem to indicate that the zygote stage is the most suitable to study the role of the cholinergic system, as at this stage, a calcium spike can be evoked by exposure to acetylcholine (ACh) or to muscarinic drugs, at any time before the nuclear breakdown. The described outcomes also open a path to a new way of considering biomarkers. In fact, most environmental factors have the capacity to interfere with the cholinergic system: stress, wounds, inflammation and pollution in general. In particular, this offers a way to investigate the presence in the environment and the degree of aggressiveness of neurotoxic contaminants, such as organophosphate and carbamate pesticides, largely used in European countries for many purposes, including agricultural pest control and medical treatment. These drugs exert their function by interfering with the regulation of the cholinergic system and the consequent electrical events. Thus, the sea urchin zygote could represent a reliable model to be used in biosensors with the capacity to translate the effect of neurotoxic pesticides, and generally of stress-inducing contaminants, in living cell responses, such as electrical responses.
Acetylcholine↗
Polysubstrate monooxygenases in Drosophila, mammals and man.
There is overwhelming evidence that polysubstrate monooxygenases play a central role in the metabolism of endogenous compounds as well as in the biotransformation of xenobiotics. These enzyme systems are of great importance in such diverse fields as insecticide resistance, mutagenicity, carcinogenicity, drug metabolism, etc. The constitutive and, in particular, the induced forms represent various products from a multigene family. This has first been shown for the mouse, but evidence is accumulating that this is also true for other mammals and for man. Also in insects a similar picture is emerging. If the regulation of cytochrome P-450 induction resembles in any way the other methods by which prokaryotes and eukaryotes cope genetically with the many forms of environmental selective pressures, it is very likely that most organisms have the genetic capacity to produce not only hundreds but probably thousands of inducible forms of cytochrome P-450 (Nebert et al., 1981). Doubtless, many fields from pest control to cancer prevention to drug safety will profit from the elucidation of the genetic mechanisms involved.
Aflatoxin B1↗
Regulation of mosquitocidal toxin synthesis in Bacillus sphaericus.
Translational lacZ fusions to the promoters of the parasporal, crystal protein (binary toxin) and 100-kDa ADP-ribosylating mosquitocidal toxin genes of Bacillus sphaericus were prepared and expression of the toxin genes monitored as beta-galactosidase activity. Transcription of the crystal protein gene fusion began immediately before the end of exponential growth and continued into stationary phase in both B. sphaericus and Bacillus subtilis but accompanied exponential-phase growth in Escherichia coli. Expression of this fusion was severely delayed in a B. subtilis spo0A mutant and decreased relative to the wild type in a B. subtilis spoIIAC background. beta-Galactosidase activity from the 100-kDa toxin gene fusion was restricted to early exponential phase in B. sphaericus, but in B.subtilis it continued into late exponential phase. Expression was about eightfold lower in B. sphaericus than B. subtilis suggesting an element of negative control in the native host.
Bacillus↗
Primary irritant contact dermatitis from synthetic pyrethroid insecticide exposure.
Synthetic pyrethroids are widely used insecticides with numerous applications, varying from food protection to general pest control. Humans are capable of tolerating greater acute and chronic exposures to the pyrethroids than to many other insecticides. An abnormal cutaneous sensation (paresthesia) is known to occur after dermal contact with the pyrethroids. Recent field studies have indicated that a primary irritant contact dermatitis may also develop. This investigation evaluated dermal irritancy from cutaneous synthetic pyrethroid application to albino rabbits. Through repeated daily applications of either fenvalerate or permethrin, a slight erythema was noted visually which correlated with increased cutaneous blood flow measured by laser Doppler velocimetry. Histopathological changes were also documented, but no significant differences were detected in edema or thermal variation.
Animals↗
Baculovirus--insect cell interactions.
Baculovirus interactions with host cells range from the physical interactions that occur during viral binding and entry, to the complex and subtle mechanisms that regulate host gene expression and modify and regulate cellular and organismal physiology and defenses. Fundamental studies of baculovirus biochemistry and molecular biology have yielded many interesting and important discoveries on the mechanisms of these virus-host interactions. Information from such studies has also resulted in exciting new strategies for environmentally sound insect pest control, and in the development and improvement of a valuable eukaryotic expression vector system. In addition a number of important and valuable model biological systems have emerged from studies of baculoviruses. These include robust systems for studies of eukaryotic transcription, viral DNA replication, membrane fusion, and apoptosis. Because functions have been identified for only a small number of baculovirus genes, we can expect many exciting new discoveries in the future and an unfolding of the complex and intricate relationship between baculoviruses and insect cells.
Animals↗
Fine structure of the neogregarine Farinocystis tribolii Weiser, 1953. Developmental stages in sporogony and parasite-host relations.
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Animals↗
A new risk of occupational disease: allergic asthma and rhinoconjunctivitis in persons working with beneficial arthropods. Preliminary data.
For some years, biological pest control has been re-evaluated as an alternative to the indiscriminate use of pesticides. The number of "bio-factories" in Europe has been constantly increasing and today more than 100 technicians work in mass rearing of arthropods. Seven cases of asthma and allergic rhinitis are reported in 13 workers engaged in the production of beneficial arthropods. The subjects suffered from attacks of asthma and rhinitis when they came into contact with eggs and scales or waste of Chrysoperla carnea, Leptinotarsa decemlineata, Ostrinia nubilalis and Ephestia kuehniella. These attacks occurred after an average exposure period of 18 months. A RAST test, prepared by Lofarma, was carried out on subjects' serum against the above-mentioned allergens and was positive in all symptomatic subjects (7 of 13) and negative in the others. This demonstrates IgE direct sensitization mediated by complete antigens.
Adult↗
Observations on the progress of chlordane contamination in humans by blood and sebum analysis.
Chlordane residues were determined in human blood and sebum samples. The residue levels in both types of samples were remarkably increased in pest control operators and in the general population living in an area heavily contaminated with chlordane. The compound with the highest level among the residues in the blood of control subjects was oxychlordane followed by trans-nonachlor and trans-chlordane, while in the sebum, the highest levels found was that of trans-chlordane followed by cis-chlordane and trans-nonachlor. The sebum residue was similar to technical chlordane in its component pattern, but it largely originated from sources other than simple exogenous contamination. Thus, sebum might be a unique and available sample source for evaluating direct exposure to technical chlordane. A progressive state of contamination was observed in residents whose homes had been treated with chlordane.
Air Pollutants↗
New answers to malaria problems through vector control?
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Aedes↗
Rapid pesticide analysis, in post-harvest plants used as animal feed, by low-pressure gas chromatography-tandem mass spectrometry.
A wide range of pesticides used to control pests in vegetables have been determined in agricultural plant waste from beans, watermelons, and melons grown in greenhouses located in a predominantly agricultural area in Southeast Spain (Almería). Analysis of the pesticides was carried out by low-pressure gas chromatography (LP-GC) with mass spectrometry in tandem (MS-MS) mode, after extraction of the lyophilized samples with dichloromethane. The influence of the sample matrix on the analysis was avoided by use of matrix-matched standards. Linearity, detection limit ( LOD), quantitation limit ( LOQ), recovery, and precision for each pesticide were calculated. The most frequently encountered pesticides were endosulfan (>73% of the analyzed samples) and buprofezin (>55% of the samples), followed by cypermethrin, pirimifos-methyl, bifentrin, and chlorpyrifos (>30% of the samples). The pesticide found at the highest concentration level was endosulfan (223.33 mg kg(-1)) in a watermelon sample.
Animal Feed↗
Ultrasound-assisted extraction of pesticides from olive branches: a multifactorial approach to method development.
A rapid and simple method has been developed for the analysis in olive branches of two insecticides currently used in olive pest control, dimethoate and alpha-cypermethrin. The effects of analytical conditions on pesticide recovery and the optimal extraction conditions were evaluated by means of a factorial design. The use of this chemometric tool in analytical method development allows the identification of the principal and interaction effects of the extraction conditions on the recovery of pesticides. It also gives information about the location of pesticide maximum recovery with minimal experimental investment. Extraction was carried out with an ultrasonic bath and the experimental conditions studied included the volume of extractant, the time of extraction, the number of extraction steps and the sample weight. The sample was further cleaned up using a Florisil solid-phase extraction cartridge. For the overall extraction procedure, recoveries of 99 % for alpha-cypermethrin and 90 % for dimethoate from the spiked samples were found for 1 g of sample extracted three times with 35 mL hexane, sonicating for 2 min in each step. The complete process including ultrasonic extraction and filtration will not require more than 15-20 min, in contrast with several hours for conventional liquid-solid extraction techniques. The proposed method allows a high sample throughput, as commonly required in monitoring studies.
Calibration↗
Environmental monitoring of the kafue river, located in the Copperbelt, Zambia.
Zambia is a country with an extensive mining industry with the majority of mines located in the Copperbelt province. Through this region of the country, the Kafue River drains and receives effluent water from mining activities as well as from other industrial point sources. In addition, production of agricultural products and pest control requires use of different pesticides in the area. Information on industrial and agricultural pollution has not been clearly identified in Zambia, and little attention has been paid to pollution control and possible impact of metals, pesticides, and other persistent compounds in the environment. The objective of this study was to introduce and to evaluate a few methodologies based on in situ bioassays for environmental assessment to promote sustainable and environmentally sound water resource management of the Kafue River. The results show that caged threespot tilapia exposed downstream of industrial points sources rapidly bioaccumulate several trace elements, i.e., Cd, Co, Cu, Cr, Ni. These elements also occurred in much higher concentrations in water samples downstream of the industrial area compared with a locality upstream. Furthermore, the use of a semipermeable membrane device (SPMD) for passive absorption of lipophilic pollutants in the water showed relatively high concentration of several pesticides, i.e., DDT with major metabolites, PCB, and dieldrin. The present study shows that only 2 weeks of in situ studies in waters contaminated by pollutants affects in situ exposed fish and that the correlation between water and tissue concentrations was relatively good. Both trace elements and persistent organic pollutants occurred in such high concentrations that they must be considered from ecotoxicological aspects and may affect aquatic animal health.
Animals↗