Toxicity of pyrethroids and repellency of diethyltoluamide in two deltamethrin-resistant colonies of Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae)

The aim of the currrent investigation was to evaluate (a) the toxicity of three pyrethroids (deltamethrin, lambdacyhalothrin, and tetramethrin); (b) the effect of these insecticides on the locomotor activity; and (c) the repellent effect of N,N-diethyl-m-toluamide (DEET) on two deltamethrin-resistant strains of Triatoma infestans, from Argentina (El Chorro and La Toma), and one susceptible strain. The resistance ratios (RRs) obtained for the La Toma strain were: > 10,769,50,7, and > 5,2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The RRs for the El Chorro strain were: > 10,769, 85.8, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The hyperactivity usually caused by the three pyrethroids was in both the deltamethrin-resistant strains compared to the susceptible reference strain. No differences were observed in the repellent effect of DEET between the three groups. These results indicate that the deltamethrin-resistant insects have a cross resistance to lambda-cyhalothrin and tetramethrin, and are also resistant to the first symptom of pyrethroid poisoning (hyperactivity). However, the sensorial process related to DEET repellency does not appear to be altered.Fil: Sfara, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Zerba, Eduardo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Alzogaray, Raúl Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Universidad Nacional de San Martín; Argentin

Sustainable pome fruit production in Patagonia, Argentina

Apple and pear production in Argentina mostly takes place in the provinces of Río Negro and Neuquén, along a valley located in an area irrigated by the rivers Neuquén, Limay and Negro. Most commonly agrochemicals applied for these cultures protection are pesticides against mite and codling moth (Cydiapomonella, L). Carbaryl,azinphos-methyl and dimethoate have been recently detected and quantified in water samples from these rivers. Heptachlor, was also found sporadically, despite its use is forbidden in our country. Although these organophosphorus pesticides use is allowed, dimethoate and azinphos-methyl, as well as carbaryl are harmful substances that exert adverse effects through inhibition of cholinesterases and carboxylesterases. Also they are responsible of eliciting antioxidant responses in different organisms. Fruit production in this region became more sustainable in the last years as the consequence of government prohibition on the use of old generation pesticides and the introduction of new generation ones. A National Program designed to avoid codling moth damage, through a sexual confusion method, was implemented in 2006. The codling moth induced damage reached 6,1% of total production in 2003 in farms that were afterwards included in the Program, and 0,73% of it, after 3 years of program development; and at the same time there was a 385 ton/year decrease in azimphos-methyl use. Improvement in management techniques for pests as San José louse and European red mite, as well as government programs for their control promoting the use of non-toxic natural compounds, will certainly contribute to achieve sustainable fruit production in Patagonia.Fil: Sfara, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; ArgentinaFil: Fonovich, Teresa Mabel. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; ArgentinaFil: Perez Coll, Cristina Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentin

Chemical Signals are Involved in the Detection and Preference of Food Sources in Blattella Germanica

The German cockroach (Blattella germanica) is a cosmopolitan omnivorous species which can take nutrients from a wide variety of sources. Its condition of pest generated interest in the study of its biology, and while there are many works regarding its feeding behavior, few approaches have been made to the relevance of the chemosensory system during foraging. Objective: In this work we studied the role of chemical stimuli in the detection and preference of food sources in B. germanica using behavioral observations. Methods: Adult males were placed in a circular experimental arena where different diet types were presented individually. Parameters associated to the detection of odors (latency to the food source, number of visits to the source) were measured in an experimental time of 15 minutes. We also measured the total amount ingested determining the weight gain of each individual, as an indicator of taste evaluation of food. Findings: Insects showed a lower latency when the source emitted a larger amount of volatile compounds, so peanut butter was detected faster compared with the other diets studied. Regarding ingestion, insects spent significantly more time on the peanut butter, indicating the presence of phagostimulants such as sugars or lipids. When sugar solutions were used as food sources, the number of visits, the time spent on the source and the amount consumed was higher when increasing sugar concentration. Insects also showed preference for the solution of higher concentration, when two sugar solutions were presented simultaneously. Latency increased and the amount of sugar ingested decreased when insects´ mouthparts were chemically blocked with N-Ethylmaleimide, a general inhibitor of chemoreception. Novelty/Improvement: These results describe how cockroaches use odors to locate food sources and chemoreceptors in their mouthparts to identify diets of higher energetic value, from information regarding the concentration and quality of the food source. Understanding the feeding behavior of cockroaches allows the design of more attractive and palatable toxic gel baits enhancing their efficacy for cockroach control

Ganadería y calidad de agua en el Delta del Paraná Desafíos y recomendaciones

La publicación presenta una serie de problemáticas asociadas al impacto de la actividad ganadera sobre la calidad del agua en humedales. Se enfoca en los efectos de la presencia del ganado, del manejo hidrológico y del uso de productos veterinarios. se realizan también una serie de recomendaciones para una ganadería más sustentable en los humedales. está destinado a productores ganaderos de la región del Delta del Paraná.Fil: Boné, Emiliano. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Casa, Valeria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Mataloni, Maria Gabriela. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Sfara, Valeria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Locomotor behaviour of Blattella germanica modified by DEET

N,N-diethyl-3-methylbenzamide (DEET) is the active principle of most insect repellents used worldwide. However, its toxicity on insects has not been widely studied. The aim of this work is to study the effects of DEET on the locomotor activity of Blattella germanica . DEET has a dose-dependent repellent activity on B. germanica. Locomotor activity was significantly lower when insects were pre-exposed to 700 μg/cm2 of DEET for 20 or 30 minutes, but it did not change when pre-exposure was shorter. Locomotor activity of insects that were pre-exposed to 2.000 μg/cm2 of DEET for 10 minutes was significantly lower than the movement registered in controls. No differences were observed when insects were pre-exposed to lower concentrations of DEET. A 30-minute pre-exposure to 700 μg/cm2 of DEET caused a significant decrease in locomotor activity. Movement was totally recovered 24 h later. The locomotor activity measured during the exposure to different concentrations of DEET remained unchanged. Insects with decreased locomotor activity were repelled to the same extent than control insects by the same concentration of DEET. We demonstrated that the repellency and modification of locomotor activity elicited by DEET are non-associated phenomena. We also suggested that the reduction in locomotor activity indicates toxicity of DEET, probably to insect nervous system.Fil: Sfara, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; ArgentinaFil: Mougabure Cueto, Gastón Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Zerba, Eduardo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; ArgentinaFil: Alzogaray, Raul Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentin

Brašno - Kruh '15

Proceedings contains 28 original research articles presented at 8th International Congress Flour – Bread ’15 and 10th Croatian Congress of Cereal Technologists Brašno – Kruh ’1

The analysis of dose-response curve from bioassays with quantal response: Deterministic or statistical approaches?

Dose-response relations can be obtained from systems at any structural level of biological matter, fromthe molecular to the organismic level. There are two types of approaches for analyzing dose-responsecurves: a deterministic approach, based on the law of mass action, and a statistical approach, based on theassumed probabilities distribution of phenotypic characters. Models based on the law of mass actionhave been proposed to analyze dose-response relations across the entire range of biological systems. Thepurpose of this paper is to discuss the principles that determine the dose-response relations.Dose-response curves of simple systems are the result of chemical interactions between reactingmolecules, and therefore are supported by the law of mass action. In consequence, the shape of thesecurves is perfectly sustained by physicochemical features. However, dose-response curves of bioassayswith quantal response are not explained by the simple collision of molecules but by phenotypicvariations among individuals and can be interpreted as individual tolerances. The expression of toleranceis the result of many genetic and environmental factors and thus can be considered a random variable. Inconsequence, the shape of its associated dose-response curve has no physicochemical bearings; instead,they are originated from random biological variations. Due to the randomness of tolerance there is noreason to use deterministic equations for its analysis; on the contrary, statistical models are theappropriate tools for analyzing these dose-response relations.Fil: Mougabure Cueto, Gastón Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Salud de la Nación Argentina; ArgentinaFil: Sfara, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín; Argentin

Repellence Produced by Monoterpenes on Rhodnius prolixus (Hemiptera: Reduviidae) Decreases After Continuous Exposure to These Compounds

Botanical monoterpenes are secondary metabolites present in essential oils produced by plants. Some of them are insect repellents. The bloodsucking bug Rhodnius prolixus Ståhl (Hemiptera: Reduviidae) is one of the main vectors of Chagas disease in the north of South America and some countries in Central America. In this study, we studied the repellence produced by two monoterpenes, menthyl acetate and geraniol, on fifth instar nymphs of R. prolixus. In the absence of other stimuli, both menthyl acetate and geraniol produced a repellent effect from 740 μg/cm² and 74 μg/cm², respectively. Pre-exposure to each monoterpene reduced the repellent activity produced by the same substance. Additionally, pre-exposure to one monoterpene decreased the behavioral response of the nymphs to the other one. The repellent effect of both monoterpenes also decreased when nymphs' antennae were previously treated with the nitric oxide donor S-nitroso-N-acetyl-cysteine.Fil: Lutz, Alejandra. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Departamento de Producción Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sfara, Valeria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Alzogaray, Raúl Adolfo. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Spatial Repellency Caused by Volatile Pyrethroids is Olfactory-Mediated in the German Cockroach Blattella germanica (Dictyoptera: Blattellidae)

Pyrethroids are synthetic insecticides that have a repellent action. This effect has been associated with an increase in the locomotor activity, which causes the avoidance of the insecticide-treated area (excito-repellency). In this work, we studied with behavior and electrophysiological recordings the occurrence of olfactory-mediated repellency caused by pyrethroids of different volatility in the German cockroach Blattella germanica (Linnaeus, 1767). Male cockroaches were spatially repelled when they were exposed to d-allethrin vapors and vapothrin vapors in a dose-dependent manner. No repellency was observed when insects were exposed to permethrin, a non-volatile pyrethroid. To confirm the role of olfaction in this phenomenon, we measured the electrical activity of the cockroaches’ antennae in response to these insecticides. There was a significant increase in the electrical activity in response to d-allethrin and vapothrin, but no increase was observed in insects exposed to permethrin. Locomotor activity of cockroaches exposed to pyrethroids was measured in order to discard excito-repellency. No changes in locomotor activity were observed for any of the insecticides. Finally, we found that volatile pyrethroids in the vapor phase cause spatial repellency in cockroaches, being the first report of an olfactory-mediated repellency phenomenon caused by pyrethroids in cockroaches.Fil: Boné, Emiliano. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Gonzalez Audino, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Sfara, Valeria. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Fumigant insecticidal activity and repellent effect of five essential oils and seven monoterpenes on first-instar nymphs of Rhodnius prolixus

The aim of this study was to evaluate the fumigant and repellent activity of five essential oils (from eucalyptus, geranium, lavender, mint, and orange oil) and seven monoterpenes (eucalyptol, geraniol, limonene, linalool, fnenthone, linalyl acetate, and menthyl acetate) on first-instar nymphs of the bloodsucking bug Bhodnius prolixus Stahl (vector of Chagas disease in several Latin American countries). Fumigant activity was evaluated by exposing the nymphs to the vapors emitted by 100 pi of essential oil or monoterpene in a closed recipient. The knockdown time 50% (KT50) for eucalyptus essential oil was 215.6 min (seven times less toxic than dichlorvos, a volatile organophosphorus insecticide used as a positive control). The remaining essential oils showed a poor fumigant activity: <50% of nymphs were knocked down after 540 min of exposure. The KT50 values for monoterpenes, expressed in minutes, were as follows: 117.2 (eucalyptol), 408.7 (linalool), 474.0 (menthone),and 484.2 (limonene). Eucalyptol was 3.5 times less toxic than dichlorvos. No affected nymphs were observed after 540 min of exposure to geraniol, linalyl acetate, or menthyl acetate. Repellency was quantified using a video tracking system. Two concentrations of essential oils or monoterpenes were studied (40 and 400 μgl cm2). Only mint and lavender essential oils produced a light repellent effect at 400 μg/ cm2. Geraniol and menthyl acetate produced a repellent effect at both tested concentrations and menthone only elicited an effect at 400 μg/cm2. In all cases, the repellent effect was lesser than that produced by the broad-spectrum insect repellent N,N-diethyl-3-methylbenzamide (DEET).Fil: Sfara, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Zerba, Eduardo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; ArgentinaFil: Alzogaray, Raúl Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentin