Uptake of acid black 210 dye by organo-montmorillonite clay minerals

Two clays rich in montmorillonite were modified and used as adsorbents. The clay minerals were modified with hexadecylpyridinium cation (HDP+) in order to obtain organo-montmorillonites, which were used for retaining acid black 210 dye from water solution. This dye is frequently used in tanning industry. The retentions of the anionic dye by organo-montmorillonites were evaluated by using complete UV-visible spectrum, analyzing the concentrations of dye solutions before (50 mg/L) and after the contact with the adsorbent. The solids were characterized by X-ray diffraction (XRD) and infrared analyses (FT-IR). The interlayer spacing of the montmorillonites increased, after organic cation exchange, from 13.0-14.9 Å to 19.0-22.0 Å and allowed the uptake of acid black 210 dye. The most disordered arrangement of HDP in montmorillonite, deduced by XRD and FT-IR analyses, was better for higher retentions of acid black dye

Intra- and interspecific interactions between aphidophagous ladybirds: the role of prey in predator coexistence

Cannibalism (CANN) and intraguild predation (IGP)may provide energy and nutrients to individuals and eliminate potential competitors. These negative competitive interactions could also affect the coexistence of predatory species. The co-occurrence of aphidophagous ladybird species in crops creates opportunities for CANN and IGP, especially when aphids become scarce. The Lotka–Volterra model predicts the coexistence of two species if intraspecific competition is stronger than interspecific interference interactions. Cycloneda sanguinea L. and Eriopis connexa (Germar) (both Coleoptera: Coccinellidae) coexist in sweet pepper crops in La Plata (Argentina) consuming mainly Myzus persicae (Sulzer) (Hemiptera: Aphididae). The present study used laboratory experiments to estimate levels of CANN and IGP by adults and larvae on eggs, and by adults on larvae, in both the presence and absence of prey (i.e., M. persicae), to explain the effect of prey on coexistence of these two predators. Levels of CANN by C. sanguinea and E. connexa were high in the absence of aphids, and decreased when prey was present. Intraguild predation was bidirectional and asymmetric. Adults and larvae of E. connexa were more voracious IG predators of C. sanguinea than vice versa, the former being the stronger IG predator and interference competitor. Eriopis connexa always won when larvae of the same instar were compared, whereas the larger larva always won when larvae were of different instars, regardless of species. In the presence of prey, CANN by both species decreased, but IGP by E. connexa on C. sanguinea remained high, suggesting that E. connexa could displace C. sanguinea via interspecific interference competition. Other factors potentially affecting the coexistence of C. sanguinea and E. connexa in sweet pepper crops are discussed.Facultad de Ciencias Naturales y MuseoCentro de Estudios Parasitológicos y de Vectore

Performance of Tetranychus urticae and Neoseiulus californicus on strawberry cultivars and assessment of the effect of glandular trichomes

Fil: Gugole Ottaviano, María Fernanda. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Sánchez, Norma Elba. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Roggiero, Martha Florencia. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Greco, Nancy Mabel. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Uptake of acid black 210 dye by organo-montmorillonite clay minerals

Two clays rich in montmorillonite were modified and used as adsorbents. The clay minerals were modified with hexadecylpyridinium cation (HDP⁺) in order to obtain organo-montmorillonites, which were used for retaining acid black 210 dye from water solution. This dye is frequently used in tanning industry. The retentions of the anionic dye by organo-montmorillonites were evaluated by using complete UV-visible spectrum, analyzing the concentrations of dye solutions before (50 mg/L) and after the contact with the adsorbent. The solids were characterized by X-ray diffraction (XRD) and infrared analyses (FT-IR). The interlayer spacing of the montmorillonites increased, after organic cation exchange, from 13.0-14.9 Å to 19.0-22.0 Å and allowed the uptake of acid black 210 dye. The most disordered arrangement of HDP in montmorillonite, deduced by XRD and FT-IR analyses, was better for higher retentions of acid black dye.Facultad de Ciencias ExactasCentro de Tecnología de Recursos Minerales y CerámicaCentro de Investigación y Desarrollo en Ciencias Aplicada

Interacciones negativas entre enemigos naturales: importancia de la presencia de presas en los cultivos

Fil: Rocca, Margarita. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Rizzo, Estefanía. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Sánchez, Norma Elba. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Greco, Nancy Mabel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

La planta de frutilla como recurso para la persistencia de Orius insidiosus en el cultivo

Fil: Pascua, Mariana S.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Rocca, Margarita. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Sánchez, Norma Elba. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Greco, Nancy Mabel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

Interacciones negativas entre enemigos naturales: importancia de la presencia de presas en los cultivos

Los enemigos naturales prestan un servicio ecológico a la agricultura ya que pueden limitar el crecimiento poblacional de las plagas. Cuando la densidad de éstas es muy baja, el canibalismo y la depredación intragremio (DIG) entre los depredadores se acrecientan. Nuestra hipótesis es que la intensidad del canibalismo y la DIG es máxima en ausencia de presas y las especies pueden coexistir cuando la densidad de la presa es suficiente. Se comparó el canibalismo de E. connexa (Ec) y C. sanguinea (Cs) sin y con áfidos, la DIG de una sobre la otra y viceversa, y para cada especie su canibalismo con la DIG por la otra. Tanto Ec como Cs realizaron canibalismo de sus huevos y larvas. La DIG fue asimétrica, siendo Ec el depredador intragremio más fuerte. En condiciones de muy baja densidad de presas, Cs podría ser excluida del cultivo. La coexistencia podría explicarse por la competencia por explotación o la utilización diferencial de los recursos de la planta en el espacio y/o en el tiempo.Natural enemies provide an ecological service to agriculture since they can limit population growth of pests. When the density of pests is very low, the cannibalism and the intraguild predation (IGP) between predators are promoted. Our hypothesis is that the intensity of cannibalism and IGP is maximum in the absence of prey and decrease when the prey density increases and the species can coexist. We compared: the cannibalism of E. connexa (Ec) and C. sanguinea (Cs) with or without aphids, the IGP of one over the other and vice versa and, for each species, the ratio between its cannibalism with IGP caused by the other species. Both Ec and Cs performed cannibalism on their eggs and larvae. The IGP was asymmetric, being Ec the strongest intraguild predator. Under very low prey density conditions, Cs could be excluded from the crop. The coexistence could be explained by scramble competition or the differential use of plant resources in space and/or time.Eje A4: Ambiente, Naturaleza y AgroecologíaFacultad de Ciencias Agrarias y Forestale

Conservation biological control in strawberry: effect of different pollen on development, survival, and reproduction of <i>Neoseiulus californicus</i> (Acari: Phytoseiidae)

Wild vegetation surrounding crops may provide temporary habitat and potential food sources for phytoseiids in different seasons. Monthly vegetation samples of wild plants adjacent to strawberry plants and wild plants in a vegetation strip close to the crop were taken. The frequency of Neoseiulus californicus, Tetranychus urticae and other mites and insects was recorded. In addition, in a laboratory assay, the survival, developmental time and fecundity of females fed on pollen of strawberry and pollen of wild plants where N. californicus was recorded during their flowering, were estimated. Pollen from Urtica urens, Lamium amplexicaule, Convolvulus arvensis, Sonchus oleraceous, Galega officinalis, and Fragaria x ananassa (strawberry) allowed development of N. californicus to adult, but not reproduction. Survival was 70-80 % when fed on pollen from S. oleraceus, G. officinalis and C. arvensis, 80-90 % when fed on pollen from U. urens and F. x ananassa, and more than 90 % when fed on T. urticae and on pollen from L. amplexicaule. In autumn and winter, U. urens, L. amplexicaule and S. oleraceous could promote the persistence of N. californicus when prey density in strawberry is low, offering T. urticae, thrips and pollen. In summer, pollen of C. arvensis and G. officinalis would contribute to the persistence of N. californicus when the strawberry crop is ending and offers scarce food resources. Although the pollen of these plants would not enable the predator population to increase, the presence of these plants in the vicinity of strawberry could contribute to the persistence of N. californicus population and help to limit T. urticae growth when this pest begins to colonize the crop.Facultad de Ciencias Naturales y MuseoCentro de Estudios Parasitológicos y de Vectore

La planta de frutilla como recurso para la persistencia de <i>Orius insidiosus</i> en el cultivo

La hipótesis de este trabajo es que la planta de frutilla ofrece a O. insidiosus sustratos apropiados para oviponer. Los objetivos fueron cuantificar la oviposición del depredador en la planta, en etapa vegetativa y en floración; e identificar las estructuras más adecuadas para la misma. En una planta se liberaron 3 ♀:1 ♂ y a las 48 hs se registró el número de huevos en láminas, nervaduras, pecíolos, peciólulos de las hojas, cáliz y pecíolos de las flores. Las plantas sin flor (n=15) y con flor (n=15) recibieron el mismo número de huevos. Esto sugiere que la disponibilidad de polen no favorecería la oviposición. Las hembras colocaron 2,34±1,37 huevos/hembra/día. En plantas sin flor las estructuras más utilizadas fueron el pecíolo y la nervadura principal, mientras que en plantas con flor fueron el cáliz y el pecíolo floral. Los resultados indican que el depredador O. insidiosus encuentra en este cultivo sustratos de oviposición, recursos importantes para su persistencia en el cultivo.The hypothesis of this work is that strawberry plant offers to O. insidiosus appropriate substrata for oviposition. The objective was to evaluate the suitability of different plant structures, in the vegetative and flowering stage, as ovipositional substrata for this predator. Three females and a male were released in a plant and, after 48 h, the number of eggs was recorded in leaf blade, ribs, petioles, petiolules of the leaves, calix and flower petioles. Plants without flower (n=15) and with flower (n=15) received the same number of eggs. This suggests that pollen availability would not favor oviposition. The females laid 2.34±1.37 eggs/female/day. In plants without flower the most used structures were petiole and primary rib, whereas in plants with flower they were calix and floral petiole. The results indicate that the predator O. insidiosus finds, in this plant, suitable substrata for oviposition, important resources for its permanence in the crop.Eje A4: Ambiente, Naturaleza y AgroecologíaFacultad de Ciencias Agrarias y Forestale