Enantiomeric Ratio Changes of Terpenes in Essential Oils from Hybrid Eucalyptus grandis × E. tereticornis and its Pure Species

Some Eucalyptus species produce oils with biological activities and the effect of their interspecifc hybridization on the enantiomeric composition of terpenes has not been reported. The enantiomeric excesses of monoterpenes in the essential oil of Eucalyptus grandis × E. tereticornis and its parental taxa were determined by gas chromatography-mass spectrometry (GC-MS), and to resolve coelutions problems by preparative high performance liquid chromatography (HPLC)and GC-MS with two columns in series. The essential oil composition of the hybrid presented qualitative and quantitative differences with the composition of its parental taxa. Great differences were found for the enantiomeric ratio in monoterpene alcohols among the three essential oils. Our results suggest that the enantiomeric analysis can be a reliable method for the study of how theinterspecifc hybridization can module the enantiomeric chemical profle in Eucalyptus essential oils. These results suggest the use of interspecifc hybridization to improve or expand the source of bioactive compounds.Fil: Naspi, Cecilia Veronica. 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: Alvarez Costa, Agustin. 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: Lucia, Alejandro. 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: Gonzalez Audino, Paola Andrea. 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: Masuh, Hector Mario. 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

Granulobasidium vellereum (Ellis &Cragin) Jülich, a promising biological control agent

Studies involving biological control of wood decay fungi and pests in forest areas are scarce. The basidiomycete Granulobasidium vellereum (Ellis & Cragin) Jülich has been isolated as wood endophyte from London Plane trees (Platanus acerifolia (Ait.) Willd). This basidiomycete produces a variety of sesquiterpenes with antifungal activity. In this study we evaluated the potential activity of G. vellereum against wood decay fungi and fungi associated with the ambrosia beetle Megaplatypus mutatus Chapuis, an important forest pest in Populus sp. A combination of in vitro assays was made, in cultures and on wood blocks. Granulobasidium vellereum’s Volatile Organic Compounds (FVOCs) were characterized and their potential role in biocontrol was assessed. Granulobasidium vellereum did not cause a significant loss of weight on P. acerifolia and Populus wood and inhibited the growth of the target fungi, mainly when inoculated first. Up to nineteen volatile compounds were determined in G. vellereum strains. The growth of all target fungi was inhibited by FVOCs and in some cases the morphology of the fungi was altered. These results indicate that G. vellereum can be used as a Biological Control Agent (BCA) of xylophagous fungi and fungi related to forest pests. Further investigations should focus on developing application strategies for M. mutatus management.Fil: Robles, Carolina Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Ceriani Nakamurakare, Esteban Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Micología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Slodowicz, Mariel Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; 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; ArgentinaFil: Carmaran, Cecilia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentin

Head lice were also affected by COVID-19: a decrease on Pediculosis infestation during lockdown in Buenos Aires

Pediculosis is a worldwide disease affecting school-aged children produced by the presence of the head louse, Pediculus humanus capitis De Geer, an obligate ectoparasite on the human scalp feeding exclusively on blood. Transmission occurs primarily through direct physical head-to-head contact. In March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak as a pandemic. COVID-19 is caused by SARS-CoV-2, a variant of the coronavirus. Therefore, on March 18, 2020, the Argentinean government established mandatory isolation for an indefinite period. This obligatory isolation interrupted regular classes avoiding direct contact between children, thus affecting the dispersal route of individuals and the evolution of head louse populations. In this study, we evaluated through an online survey how confinement affected the prevalence of lice during lockdown compared to the situation prior to confinement. The survey allowed to discriminate the different control strategies, the number of treatments, and the amount of insects recorded by parents. Data of 1118 children obtained from 627 surveys were analyzed. As the main result, it was observed that prevalence of lice decreased significantly from before (69.6%) to during (43.9%) COVID-19 lockdown. Moreover, head lice infestation was more effectively controlled in households with up to 2 children in comparison to households with 3 or more children. This is the first study that analyzed the prevalence of head lice during COVID-19 pandemic. In addition, this work demonstrated the impact of social distance in the population dynamics of head lice and how it could affect the control strategies in the future.Fil: Galassi, Federico Gabriel. 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: Ortega Insaurralde, Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Adjemian, Victor. 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: Gonzalez Audino, Paola Andrea. 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: Picollo, Maria Ines. 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: Toloza, Ariel Ceferino. 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

Respuesta de Pediculus humanus capitis (Phthiraptera: Pediculidae) a volátiles del cuero cabelludo humano y a sus componentes aislados

Elpiojo de la cabeza Pediculus humanuscapitis (De Geer) es un ectoparásito humano cosmopolita que causa lapediculosis, una de las infestaciones humanas más frecuentes (Toloza et al.,2009). La infestación de piojos es molesta y puede causar picazón, pérdida desueño y sanción social (Burgess et al., 2004). El mecanismo de cómo los piojosreconocen a su anfitrión y las señales implicadas son poco conocidas, así comolos compuestos químicos que están implicados en este comportamiento. En esteestudio se evaluó utilizando un T-olfatómetro, la respuesta de los piojos de lacabeza al olor del cuero cabelludo humano. Además, identificamos los componentesvolátiles emanados por la cabeza humana y evaluamos la actividad atractiva orepelente de sus componentes principales puros. Los volátiles se recogieron através de SPME (fibra) y los compuestos se analizaron por CG-MS. Se identificaron veinticuatro componentes en el olor delcuero cabelludo humano, de los cuales los cuatro principales fueron: nonanal,sulcatona, geranilacetona y ácido palmítico. Los piojos de la cabeza fueronaltamente atraídos por las muestras volátiles del cuero cabelludo humano, yfueron atraídos o repelidos por los componentes principales individuales segúnsu masa. Un hallazgo significativo de nuestro estudio fue demostrar que laactividad nonanal depende de la masa del compuesto que es repelente a altasconcentraciones y atrae a bajas concentraciones.Fil: Galassi, Federico Gabriel. 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: Toloza, Ariel Ceferino. 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: Picollo, Maria Ines. 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: Gonzalez Audino, Paola Andrea. 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; Argentina1as Jornadas de la Unidad de Investigación y Desarrollo Tecnológico para la DefensaArgentinaUnidad de Investigación y Desarrollo Estratégico para la Defens

Chemical Communication of the Head Lice with the Human Host

Purpose of Review: Transmission of head lice occurs primarily by direct host-to-host contact and via inanimate objects, called fomites. As for other hematophagous insects, chemical cues are likely involved in host detection, at least in the close range for the case of head lice. Recent Findings: The revision of the literature on the effect of chemical cues from the host on head lice behavior showed that volatiles in a combination but also individually from the human scalp trigger an attraction response on head lice. Studies also show that both infested and non-infested individuals have similar chemical profiles and that lice show no preference for volatiles from either group. Concerning the odors from different body parts, volatiles from scalp, arm, and foot produced similar attraction to lice when compared to volatiles from the scalp. However, complete extracts from different parts of the body (scalp, arm, and foot), lice seem to show a clear preference towards samples from the scalp over samples from the arm or foot. Summary: There is strong evidence of chemical communication between the head louse and its human host. Understanding the biochemical communication between head lice and the human host is essential not only to understanding the biological mechanisms of transmission but also to develop new tools for head lice control.Fil: Galassi, Federico Gabriel. 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: Gonzalez Audino, Paola Andrea. 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

The Response of Susceptible and Pyrethroid-Resistant Blattella germanica (Dyctioptera: Blattellidae) to Shelter-Associated Cues

In this work, it was studied the role of faeces in the location and permanence in a shelter in susceptible and pyrethroid-resistant individuals of Blattella germanica (Linnaeus 1767). Additionally, the effect of different concentrations of palmiticacid on the modulation of these behaviours was tested. A shelter constituted by a square cardboard structure was offered tosusceptible as well as to resistant specimens. The shelter bases were treated with faecal extracts obtained from susceptibleor resistant cockroaches, or with solutions of palmitic acid. The behaviour of susceptible as well as resistant specimens wasanalysed using infrared videography software. Susceptible’s faecal extract attracted both specimens since the time spent bycockroaches to locate the treated shelters was lower, whereas the faecal extract from resistant insects did not elicit any effecton both strains. Faecal extracts showed an arrestant effect on both strains, suggested by the time spent inside the shelter thatwas significantly higher in their presence. On the other hand, treatment with palmitic acid produced an attractant or a repel-lent effect depending on the concentration and strain. The tested lower concentration was attractant to susceptible insects, butdid not produce any effect on resistant ones. In addition, the higher concentrations did not produce any effect on susceptibleindividuals, but resulted repellent for resistant ones. Palmitic acid did not produce an arrestant effect on the strains as therewas not an increase in time spent inside the shelter in the presence of this substance. An increase in the number of visits tothe shelter and to the periphery was also observed in shelters treated with the faecal extract and with the lower concentrationof palmitic acid. These results show that compounds of the susceptible faeces were attractant to cockroaches of both strains,while faecal extracts from resistant insects were not. Moreover, a dual effect of palmitic acid was observed, being attractantat low concentrations and repellent as concentration increased. Additionally, a difference in the concentration threshold atwhich the effect of this substance changes was observed between strains.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. 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

Behavioral Response of Aedes aegypti (Diptera: Culicidae) Larvae to Synthetic and Natural Attractants and Repellents

Aedes aegypti (L.) (Diptera: Culicidae) is the key vector of three important arboviral diseases: dengue, yellow fever, and chikungunya. Immature stages of this species inhabit human-made containers placed in residential landscapes. In this study, we evaluated a few compounds in a sensitive behavioral assay with Ae. aegypti larvae. The orientation of larvae to different compounds was surveyed using a performance index (PI). The PI represents the response to each odorant, where a value of + 1 is indicative of full attraction and -1 represents complete repulsion. The widely used insect repellent N, N-diethyl-m-toluamide elicited a significantly negative PI, as did acetophenone and indole. A yeast extract, a known food source, elicited a significantly positive PI, as did 2-methylphenol, 1-octen-3-ol, 3-methylphenol, and fish food. On the other hand, no response was observed for the essential oil of Eucalyptus grandis x Eucalyptus camaldulensis at the concentration evaluated. Pretreatment of larvae with N-ethylmaleimide and ablation of the antennae resulted in a suppression of behavioral responses. The overall mobility of ablated larvae was indistinguishable from unablated controls, and absence of any visible locomotor dysfunction was observed. This work is a contribution to the study of the chemical ecology of disease vectors with the aim of developing more efficient tools for surveillance and control. Natural and synthetic compounds attractive to Ae. aegypti larvae should be incorporated into integrated pest management programs through the use of baited traps or by improving the efficacy of larvicides commonly used in control campaigns.Fil: Gonzalez, Paula 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; ArgentinaFil: Gonzalez Audino, Paola Andrea. 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: Masuh, Hector Mario. 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

Oviposition Behavior in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in Response to thePresence of Heterospecific and Conspecific Larvae

In mosquitoes, location of suitable sites foroviposition requires a set of visual, tactile, and olfactory cues that influencesfemales before laying their eggs. The ability of gravid females to distinguishamong potential oviposition sites that will or will not support the growth,development, and survival of their progeny is critical. Aedes aegypti (L.) andAedes albopictus (Skuse) share ecological niches, being highly competitive inlarval stage. We studied the oviposition behavior of both species in thepresence of larvae of one or the other species (heterospecific or conspecificlarvae). The number of eggs laid by gravid females on oviposition sites (water withdifferent or the same species of Aedes larvae) were compared. The presence anddensity of heterospecific or conspecific larvae had a positive or negative effecton the ovipositional responses, measured as an oviposition activity index. Forboth species, the oviposition was not affected by heterospecific larvae withdensities between 10 and 100 larvae in water, but a strong attractant behaviorwas observed for a density of 500 larvae in water. For Ae. albopictus in thepresence of larvae of the same species (conspecific oviposition), we observed anattractant effect for larvae density of 10 but not for 100 or 500 larvae inwater. Instead, for Ae. aegypti, we observed attraction only for 100 larvae,not for 10 or 500 larvae. Results presented here provide an additional insight aboutoviposition behavior responses of gravid females in the presence of conspecificand heterospecific larvae in breeding sites.Fil: Gonzalez, Paula 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. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Gonzalez Audino, Paola Andrea. 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. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Masuh, Hector Mario. 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. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentin

Electrophysiological and behavioural response of Aedes albopictus to n-heinecosane, an ovipositional pheromone of Aedes aegypti

Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae) are highly anthropophilic mosquito species and potential vectors of dengue and yellow fever. The location of suitable sites for oviposition requires a set of visual, tactile, and olfactory cues that influence females before they lay their eggs. In this study, the effect of n-heneicosane, a recognized oviposition pheromone of Ae. aegypti, on the olfactory receptors of the antennae of Ae. aegypti and Ae. albopictus was studied using electroantennographic detection coupled to gas chromatography (GC-EAD). A significant electroantennographic response to n-heneicosane in adult females of both mosquito species was observed. In addition, gravid Ae. albopictus females laid more eggs in substrate treated with n-heneicosane at 0.1, 1, or 10 p.p.m. than in the control, denoting oviposition attractancy. Conversely, at 30, 50, 100, and 200 p.p.m., more eggs were laid in the control substrate, indicating oviposition repellency. Analysis of the larval cuticle by GC and mass spectrometry confirmed the presence of n-heneicosane in the cuticles of Ae. albopictus larvae. The species-specific role of n-heneicosane as an oviposition pheromone in Ae. aegypti and its significance as a behaviour modifier of Ae. albopictus in breeding sites is discussed. Entomologia Experimentalis et Applicata.Fil: Gonzalez, Paula 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: 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. Universidad Nacional de San Martín; ArgentinaFil: Masuh, Hector Mario. 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