Evaluation of Mesocyclops annulatus (Copepoda: Cyclopoidea) as a control agent of Aedes aegypti (Diptera: Culicidae) in Argentina.

We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.Fil: Marti, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Micieli, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Scorsetti, Ana Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Liljesthrom, Gerardo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

The sublethal effects of the entomopathic fungus <i>Leptolegnia chapmanii</i> on some biological parameters of the dengue vector <i>Aedes aegypti</i>

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini

The sublethal effects of the entomopathic fungus <i>Leptolegnia chapmanii</i> on some biological parameters of the dengue vector <i>Aedes aegypti</i>

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini

The sublethal effects of the entomopathic fungus <i>Leptolegnia chapmanii</i> on some biological parameters of the dengue vector <i>Aedes aegypti</i>

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini

New records of hypocrealean fungi infecting aphids and whiteflies: Pathogenicity against Myzus persicae and interaction with its predator Eriopis connexa

Occurrence of hypocrealean entomopathogenic fungi in Argentina is reported. Bioassays were performed to evaluate their pathogenicity against Myzus persicae and Eriopis connexa. The findings underscore the importance of preserving these fungi and of investigating their potential for vector control.Fil: Scorsetti, Ana Clara. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pelizza, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; ArgentinaFil: Cabello, Marta Noemí. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentin

Pathogenic fungi of insects from Argentina (Zygomycetes: Entomophthorales)

Three species of Entomophthorales entomopathogenic fungi (Zygomycotina: Zygomycetes) have been identified from insects in agricultural crops (Buenos Aires Province, Argentina): Zoophthora radicans Batko (Brefeld); Entomophthora planchoniana Cornu and Pandora gammae (Weiser) Humber. Fungal structure measurements are reported.Centro de Estudios Parasitológicos y de Vectore

Control capacity of the LPSc 1067 strain of Beauveria bassiana (Ascomycota: Hypocreales) on different species of grasshoppers (Orthoptera: Acrididae: Melanoplinae), agricultural pests in Argentina

Grasshoppers affect agriculture worldwide, causing serious economic damage. Currently, the application of chemical insecticides against grasshoppers is the only effective strategy, even considering the significant environmental concern. This study aimed to test the entomopathogenic fungi Beauveria bassiana (LPSc 1067) as biocontrol agent on six harmful grasshopper species in Argentina. Significant differences were observed (DF= 5; F= 9.93; P&lt;0.0001) when considering B. bassiana pathogenicity on third-instar nymphs of the different grasshopper species. The highest mortality (100%) was registered on Trimerotropis pallidipennis and Dichroplus maculipennis nymphs while the lowest mortality (48.6 ±3.5%) was observed on Scotussa lemniscata nymphs. The lowest mean survival time (MST) was recorded for T. pallidipennis (3.5 ±0.15 days) and the highest MST was observed on Dichroplus pratensis nymphs (7.48 ±0.28 days). Results suggest that B. bassiana LPSc 1067 may constitute an excellent candidate to be further studied as biological control agent of T. pallidipennis and D. maculipennis. Highlights: Melanoplinae grasshoppers include several species considered plagues. Entomopathogenic fungi as biocontrol agents are considered excellent alternatives to chemical control. The efficacy of bassiana (LPSc 1067) on six grasshopper species of Argentina. The isolate LPSc 1067 could be considered a biological controller pallidipennis and D. maculipennis.Grasshoppers affect agriculture worldwide, causing serious economic damage. Currently, the application of chemical insecticides against grasshoppers is the only effective strategy, even considering the significant environmental concern. This study aimed to test the entomopathogenic fungi Beauveria bassiana (LPSc 1067) as biocontrol agent on six harmful grasshopper species in Argentina. Significant differences were observed (DF= 5; F= 9.93; P&lt;0.0001) when considering B. bassiana pathogenicity on third-instar nymphs of the different grasshopper species. The highest mortality (100%) was registered on Trimerotropis pallidipennis and Dichroplus maculipennis nymphs while the lowest mortality (48.6 ±3.5%) was observed on Scotussa lemniscata nymphs. The lowest mean survival time (MST) was recorded for T. pallidipennis (3.5 ±0.15 days) and the highest MST was observed on Dichroplus pratensis nymphs (7.48 ±0.28 days). Results suggest that B. bassiana LPSc 1067 may constitute an excellent candidate to be further studied as biological control agent of T. pallidipennis and D. maculipennis. Highlights: Melanoplinae grasshoppers include several species considered plagues. Entomopathogenic fungi as biocontrol agents are considered excellent alternatives to chemical control. The efficacy of bassiana (LPSc 1067) on six grasshopper species of Argentina. The isolate LPSc 1067 could be considered a biological controller pallidipennis and D. maculipennis.

Evaluation of <i>Mesocyclops annulatus</i> (Copepoda: Cyclopoidea) as a control agent of <i>Aedes aegypti</i> (Diptera: Culicidae) in Argentina

We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.Facultad de Ciencias Naturales y Muse

COMPATIBILIDAD ENTRE HONGOS ENTOMOPATÓGENOS ENDÓFITOS, EXTRACTOS VEGETALES E INSECTICIDAS BIORRACIONALES PARA EL CONTROL INTEGRADO DE Bemisia tabaci GENADIUS (HEMIPTERA: ALEYRODIDAE) EN CULTIVOS HORTÍCOLAS

Los cinturones periurbanos de la provincia de Buenos Aires comprenden unas 16.000 hectáreas, de las cuales el 79% pertenecen al Cinturón Hortícola Platense en el que se producen unas 75.000 toneladas al año de hortalizas. Los cultivos más importantes son los de fruto como el tomate, pimiento y berenjena en los cuales se produce el mayor empleo de agroquímicos aplicándose de manera preventiva. Bemisia tabaci es una de las plagas más relevantes de cultivos hortícolas, provocando daños directos con el aparato bucal en los tejidos vegetales para obtener el floema y daños indirectos como la excreción de honeydew los que favorece el desarrollo de mohos, además transmiten virus patógenos que son los que mayores pérdidas producen. En la horticultura, se emplean insecticidas químicos para disminuir las poblaciones de esta plaga lo que hace necesario que se establezcan enfoques de control más global, combinando adecuadamente todas las medidas de control disponibles dentro del marco del MIP. La utilización de hongos entomopatógenos como endófitos es una herramienta que mejora la eficacia del control biológico efectuado por estos hongos. Como endófitos, los entomopatógenos, presentan ventajas frente a otros métodos de aplicación ya que están menos expuestos al daño provocado por la radiación UV y a condiciones microclimáticas adversas y son compatibles con otros grupos de enemigos naturales. Por otro lado, los extractos botánicos constituyen una variada fuente de moléculas bioactivas con capacidad entomocida, cuya importancia ha sido destacada en las últimas décadas. Si bien existen algunos reportes previos, el estudio de la compatibilidad de los extractos vegetales con hongos entomopatógenos como endófitos ha sido muy poco explorado y no existen registros sobre su utilización conjunta con químicos para el control de B. tabaci en nuestro país. La importancia de reducir la utilización de estos últimos mediante el empleo combinado de estrategias de control biológico dentro del marco de un MIP, fundamentan este tema de investigación. Por lo expuesto anteriormente, el presente proyecto tiene como principal finalidad evaluar la compatibilidad de hongos entomopatógenos, con extractos botánicos e insecticidas de bajo impacto ambiental. Además, determinar la capacidad endofítica de los entomopatógenos en plantas hortícolas y determinar efectos sinérgicos o antagónicos de la combinación de estos tratamientos sobre la supervivencia y desarrollo de B. tabaci

Production of oogonia and oospores of Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) in Aedes aegypti (L.) larvae at different temperatures

The aquatic oomycete fungus Leptolegnia chapmanii Seymour is pathogenic to mosquito larvae, but it has been little studied since it was first isolated. Although studies have been performed on different biological isolates of L. chapmanii around the world, they were made on zoospores and a very little or even nothing is known about the sexual stage (oogonia and oospores), which allows L. chapmanii to remain in the environment when conditions are not favorable. The main objective of this study was to determine the relationship between temperature and time of onset of L. chapmanii oogonia and oospores in Ae. aegypti larvae. Leptolegnia chapmanii-infected IV instar Ae. aegypti larvae were incubated at different temperatures between 5 and 45°C and photoperiod-controlled for 90 days. The number of oogonia and oospores was examined daily for each tested temperature. As was expected, low temperatures extended the times of oogonia formation, as much as seven times. Likewise, temperatures significantly affect the number of oogonia produced.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini