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Search Results: 1 - 10 of 2978 matches for " Pallini Angelo "
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Interactions mediated by predators in arthropod food webs
Venzon, Madelaine;Pallini, Angelo;Janssen, Arne;
Neotropical Entomology , 2001, DOI: 10.1590/S1519-566X2001000100002
Abstract: studies on interactions among plants, herbivores and natural enemies are important for understanding population dynamics of species in food webs, but they are also important for the practice of pest control with natural enemies. biological control programs heavily rely on the occurrence of trophic cascades, where the addition of one natural enemy causes a decrease of pest densities and an increase of plant biomass. however, when more that one natural enemy is used to control various pests in the same system, artificial food webs are created and simple tritrophic interactions change to more complicated ones. the occurrence of complex interactions and omnivory in these food webs may modify the sign and the strength of direct effects of natural enemies on pests. in this paper, we show and discuss the experimental results on interactions mediated by predators in an artificial food web that occurs on cucumber plants in greenhouses where biological control is applied. the two pests in this food web are the two-spotted spider mite tetranychus urticae koch, and the western flower thrips frankliniella occidentalis (pergande). the predatory mites phytoseiulus persimilis athias-henriot and neoseiulus californicus (mcgregor) are used to control spider mites, and the generalist predatory bug orius laevigatus (fieber) and a specialist predatory mite neoseiulus cucumeris (oudemans) are predators of thrips. results from behavioural studies showed that some of these species are attracted to the same patch and do not avoid each other's presence. we show some complex interactions arising from the meeting of these species: (a) the intraguild predation by o. laevigatus on p. persimilis, (b) the use of spider-mite web as a refuge by thrips larvae against their predators. the consequences of such interactions for population dynamics of predators and prey and their implications for success of biological control are discussed.
INTEGRACIóN DE CONTROL BIOLóGICO Y DE PRODUCTOS ALTERNATIVOS CONTRA Tetranychus urticae (ACARI: TETRANYCHIDAE)
Soto,Alberto; Oliveira,Hamilton G.; Pallini,Angelo;
Revista U.D.C.A Actualidad & Divulgación Científica , 2011,
Abstract: tetranychus urticae is an important pest associated with strawberry, due to its high densities and plant damage. farmers use acaricides in large volumes without complying with the window between the last application and harvest, resulting on toxic residues in fruits, as well as pest populations resistant to pesticides, decrement of beneficial organisms, mammalian toxicity and environmental pollution. therefore, it is necessary to generate new alternatives for the control of this mite. the aim of this work was to evaluate the toxic effect of commercial neem-based products on the mites t. urticae and phytoseiulus macropilis, through a combined analysis using both, lethal and sublethal concentrations. tetranychus urticae populations were controlled in strawberry plants when neem was used at or below lc95 concentrations. the application of the neem-based products, neem pro, organic neem and natuneem at cl95, and when the instantaneous predator?s rate of population increase ri = 0.1, represents a viable alternative to be considered for the control of the phytophagous mite t. urticae.
EFECTO LETAL Y SUBLETAL DE PRODUCTOS ALTERNATIVOS CONTRA TETRANYCHUS EVANSI (ACARI: TETRANYCHIDAE)
Soto G.,Alberto; Venzon,Madelaine; Pallini,Angelo;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2012,
Abstract: the phytophagous mite tetranychus evansi is characterized by its high reproductive, capacity which allows for its ability to attain high populations in a short time and cause economic damage. the objective of this study was to evaluate commercial products based on azadirachtina and syrup sulfocálcico to control t. evansi in greenhouses. lethal toxicity and sublethal effects on population growth (ri) of t. evansi products neem pro (0.08 and 0.07 mg/l of azadirachtina), natuneem (1.4 and 0.89 mg ai/l), organic neem (0.37 and 0.28 mg ai/l) and lime sulphur (1.0 and 0.6% to 31.5 °bé) were initially studied in the laboratory. lethal toxicity and sublethal effects on population growth (ri) of t. evansi products neem pro (0.08 and 0.07 mg/l of azadirachtina), natuneem (1.4 and 0.89 mg ai/l), organic neem (0.37 and 0.28 mg ai/l) and lime sulphur (1.0 and 0.6% to 31.5 0bé) were initially studied in the laboratory. later in a greenhouse, the control potential for concentrations corresponding to the lc95 of the products was evaluated and those where population growth was stable (ri =0). experimental design, was completely randomized, with three replicates. application of the products resulted in the improved efficiency of control over time, and this efficiency increased with the duration of exposure. the reduction percentage of phytophagous mite population was over 98%, after ten days of application. the management of t. evansi on tomatoes could be made possible by the use of products based on azadirachtina and syrup sulfocálcico.
INTEGRACIóN DE CONTROL BIOLóGICO Y DE PRODUCTOS ALTERNATIVOS CONTRA Tetranychus urticae (ACARI: TETRANYCHIDAE) INTEGRATION OF BIOLOGICAL CONTROL AND ALTERNATIVE PRODUCTS AGAINST Tetranychus urticae (ACARI: TETRANYCHIDAE)
Alberto Soto,Hamilton G. Oliveira,Angelo Pallini
Revista U.D.C.A Actualidad & Divulgación Científica , 2011,
Abstract: Tetranychus urticae es una importante plaga asociada al cultivo de fresa debido a las altas densidades poblacionales alcanzadas y a los da os ocasionados a las plantas. Los productores utilizan acaricidas en grandes volúmenes sin cumplir los periodos de carencia, ocasionando residuos tóxicos en los frutos, desarrollo de poblaciones resistentes a los productos, destrucción de organismos benéficos, intoxicación de mamíferos y contaminación del medio ambiente. Por lo tanto, es necesario generar otras alternativas de manejo de este ácaro plaga. El objetivo de este trabajo fue evaluar, mediante el análisis conjunto de la concentración letal y subletal, la acción tóxica de productos comerciales a base de nim sobre los ácaros T. urticae y Phytoseiulus macropilis. Fueron controladas poblaciones de T. urticae en plantas de fresa cuando se emplearon concentraciones correspondientes a CL95 de los productos alternativos a base de nim, y también cuando se utilizaron concentraciones inferiores. La aplicación de los productos a base de nim, Neem Pro, Organic Neem y Natuneem en la CL95 y cuando la tasa instantánea de crecimiento poblacional ri=0,1 para el predador representan una alternativa viable para el control del ácaro fitófago T. urticae. Tetranychus urticae is an important pest associated with strawberry, due to its high densities and plant damage. Farmers use acaricides in large volumes without complying with the window between the last application and harvest, resulting on toxic residues in fruits, as well as pest populations resistant to pesticides, decrement of beneficial organisms, mammalian toxicity and environmental pollution. Therefore, it is necessary to generate new alternatives for the control of this mite. The aim of this work was to evaluate the toxic effect of commercial neem-based products on the mites T. urticae and Phytoseiulus macropilis, through a combined analysis using both, lethal and sublethal concentrations. Tetranychus urticae populations were controlled in strawberry plants when neem was used at or below LC95 concentrations. The application of the neem-based products, Neem Pro, Organic Neem and Natuneem at CL95, and when the instantaneous predator’s rate of population increase ri = 0.1, represents a viable alternative to be considered for the control of the phytophagous mite T. urticae.
Genetic similarity among Agistemus pallinii Matioli et al (Acari: Stigmaeidae) found in citrus orchards in Vi?osa, Minas Gerais State, Brazil
Matioli, André L;Pallini, Angelo;Tavares, Mara G;
Neotropical Entomology , 2009, DOI: 10.1590/S1519-566X2009000200015
Abstract: stigmaeidae are very important predators of mite and insect pests on several crops in brazil. it is considered the second most important family of predatory mites in citrus orchards in brazil. however, their identification, especially that of the members of the genus agistemus, is rather difficult based only on morphology. hence, this study describes the use of random amplified polymorphic dna (rapd-pcr) markers to determine the genetic similarity of an agistemus pallinii matioli et al population found in 2004 in a citrus orchard in vi?osa, minas gerais state, brazil, preying on panonychus citri (mcgregor). amplifi cations were performed with 12 random primers (opaa8, opaa19, opab1, opab5, opab18, opac9, opac17, opac19, opad10, opae9, opae12 and opae17), which generated 119 bands, with 53.8% polymorphism. the coefficients of genetic similarity among the individuals ranged from 0.68 to 0.99, indicating a high genetic similarity among them. the 3d projection analysis clustered the majority of individuals confirming their high similarity. though individuals of a. pallinii are minute (± 360 μm long), the pcr-rapd technique can still be used for their identification, complementing morphological analyses or for comparison of populations collected in different geographic regions. this is the first molecular study carried out with stigmaeid mites.
ANáLISIS DE LA COMPOSICIóN QUíMICA DE LA CUTíCULA DE TETRANYCHUS EVANSI BACKER & PRITCHARD Y DE TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE)
Soto G,Alberto; Moreira,Márcio Dionizio; Pallini,Angelo;
Boletín Científico. Centro de Museos. Museo de Historia Natural , 2011,
Abstract: the analysis of arthropods chemical composition is important in taxonomy for recognition of species difficult to differentiate, in ecology, for behavioral analyses, and in selectivity studies of artificial and natural compounds, and, therefore, it is important for pest control. the objective of this study was to evaluate the chemical composition of the t. urticae and t. evansi mites cuticle. chromatographic analyses of extracts were performed by gas chromatography coupled to mass spectrometry (cgms). identification of compounds was based on the comparison of retention times with standards, on the kovats' index calculation and the analysis of mass spectra obtained for each registered peak on the chromatogram. relative concentration of compounds present in the cuticle, the polarity of these compounds and their total relative concentration, and the differential presence of compounds in the cuticle of the two mite species were evaluated. the most abundant compounds in the cuticle of both mite species were hexadecanoic acid (palmitic acid), 9,12-octadecadienoico acid (linoleic acid), 9,12,15-octadecatrienoic acid-methyl ester (methyl linoleate) and octadecanoic acid (oleic acid or stearic). t. urticae cuticle has from 2.07 to 3.67 times more hexane extractable compounds than t. evansi cuticle . the total polar compound concentration was 2.15 to 3.71 times higher in t. urticae and the quantity of the most abundant compounds present in both species was 2.34 to 5.66 times higher in t. urticae.
Response of the predatory mite Phytoseiulus macropilis (Banks) to volatiles produced by strawberry plants in response to attack by Tetranychid mites (Acari: Phytoseiidae: Tetranychidae)
Fadini, Marcos A M;Venzon, Madelaine;Oliveira, Hamilton;Pallini, Angelo;Vilela, Evaldo F;
Neotropical Entomology , 2010, DOI: 10.1590/S1519-566X2010000200016
Abstract: the attack of phytophagous mites may induce plants to produce volatiles, which in turn may attract predators. the occurrence of multiple phytophagous infestations on plants may influence predator response. in this paper, we investigated whether the attraction of the predatory mite phytoseiulus macropilis (banks) to phytophagous-infested plants would change with the simultaneous presence of two tetranichid mites oligonychus ilicis (mcgregor) and tetranychus urticae koch. while the former species is rarely found on strawberry plants and is only occasionally found in association with p. macropilis, the latter is commonly found on strawberry plants and is frequently found in association with p. macropilis. y-tube olfactometer test assays demonstrated that the predator preferred plants infested with t. urticae, avoided plants infested with o. ilicis, and had no preference for plants infested with both phytophagous mite species. these results indicated that the presence of a non-prey species (o. ilicis) on a given plant can alter the response of the predator to one of its prey (t. urticae). the consequences of the predatory behavior determined in this study on the predator ability to control t. urticae population on strawberry plants are discussed.
Herbivoria de Tetranychus urticae Koch (Acari: Tetranychidae) induz defesa direta em morangueiro?
Fadini, Marcos A.M.;Lemos, Walkymario P.;Pallini, Angelo;Venzon, Madelaine;Mour?o, Sheila A.;
Neotropical Entomology , 2004, DOI: 10.1590/S1519-566X2004000300003
Abstract: plants of strawberry fragaria x ananassa may present mechanisms of direct and indirect defenses against herbivores. such defenses may influence behaviour and development of phythophagous mites and their natural enemies, thereby reducing herbivory rate. we tested the effect of pre-infestation of strawberry plants by tetranychus urticae koch on the development and reproduction of the mite species. strawberry plants (cultivar iac campinas) were divided into two groups: plants without and plants with pre-infestation of t. urticae. the length of immature phases, the number of eggs per female and the survival of mites were not altered by the pre-infestation. these results may be associated to either the absence or low level of induced resistance of the cultivar iac campinas or perhaps the pre-infestation was insufficient to induce defenses. the reported resistance of this cultivar to t. urticae could be related to indirect defenses.
Domácias do cafeeiro beneficiam o ácaro predador Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)?
Matos, Cláudia H.C.;Pallini, Angelo;Chaves, Fredson F.;Galbiati, Carla;
Neotropical Entomology , 2004, DOI: 10.1590/S1519-566X2004000100011
Abstract: coffee plants have domatia on their leaves harboring mites, and the predatory mites can also use such structures. here we evaluated the effect of the domatia on the predatory mite iphiseiodes zuluagai denmark & muma, manipulating these structures on the leaves of coffea arabica l. var. catuaí. the tests were done using arenas made of coffee leaves placed up side down inside petri dishes. the survivorship of i. zuluagai was evaluated when released on leaves with closed domatia (t1); leaves with open domatia plus prey (t2) and leaves with open domatia without prey (t3). the experiment was checked every 24h, measuring the number of alive adults, oviposition site and the number of i. zuluagai eggs/treatment. significant difference was found between treatments. mites were alive until the end of the experiments on leaves with open domatia (t2 and t3), which did not happen on leaves with closed domatia (t1). the predators oviposited preferentially inside the domatia on treatments with open domatia, and on the edge of the leaves, next to the moist cotton bordering the leaves, on the treatment with closed domatia. the results indicate the role of domatia on the survivorship of the predators on the coffee plants, suggesting a possible mutualist interactions plant-predator. on coffee crops, a mutualistic plant-predator interaction mediated by domatia could be used in practices of natural biological control, selecting coffee plants with domatia to harbor predatory mites and thereby protecting plants against harmful herbivore mites.
Distribui??o espacial de ácaros fitófagos (Acari: Tetranychidae) em morangueiro
Fadini, Marcos A.M.;Oliveira, Hamilton G.;Venzon, Madelaine;Pallini, Angelo;Vilela, Evaldo F.;
Neotropical Entomology , 2007, DOI: 10.1590/S1519-566X2007000500021
Abstract: many phytophagous mites can attack strawberry plants, fragaria x ananassa, among them the southern red mite, oligonychus ilicis mcgregor, and the two-spotted spider mite, tetranychus urticae koch. they are found together feeding on the same plant on the upper and underside of the leaves, respectively. here we studied the choice for feeding sites of o. ilicis and t. urticae on strawberry plants. the first hypothesis tested whether the feeding site choice would be related to the fitness of the species. the second hypothesis dealt whether the feeding site would be determined by the presence of a heterospecific mite. we evaluated the preference, biology and reproductive success of o. ilicis and t. urticae on the under and upper side surface of strawberry leaves infested or not by the heterospecific. o. ilicis preferred to stay on the upper side surface while t. urticae preferred the underside. the preference for the leaf surface correlated with the reproductive success of the species (measured by the intrinsic growth rate). the choice pattern of feeding sites did not alter when the choice test was applied using sites previously infested by heterospecific. although o. ilicis and t. urticae, apparently, do not interact directly for feeding sites, there is a chance that the first species induces defenses in strawberry plant enabling to reduce the fitness of the second species. the possibility of those species stay together on strawberry plant increases the damage capacity to the culture.
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