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Effect of silicon applied to wheat plants on the biology and probing behaviour of the greenbug Schizaphis graminum (Rond.) (Hemiptera: Aphididae)
Goussain, Marcio M.;Prado, Ernesto;Moraes, Jair C.;
Neotropical Entomology , 2005, DOI: 10.1590/S1519-566X2005000500013
Abstract: the effect of silicon-treated wheat plants (triticum aestivum l.) on the greenbug, schizaphis graminum (rond.) (hemiptera: aphididae) was evaluated. plants were treated with silicon incorporated to the soil and by foliar spraying. aphid development was evaluated by observing the duration of the pre-reproductive, reproductive and post-reproductive periods, as well as fecundity and longevity. probing behaviour was investigated by using the dc electrical penetration graphs (epg) technique and a "honeydew clock". silica treated plants had a clear adverse effect on aphid development. stylet penetration was not affected by treatments showing no physical barriers by the plant tissue. however, stylet was withdrawn more often on plants treated with silica, resulting in reduction of probing time. sieve elements were reached equally by aphids in all treatments and the insects remained ingesting phloem sap for similar periods. however, honeydew excretion was highly reduced indicating lower sap ingestion rate or higher sap retention inside the body. chemical changes and induced resistance are possibly related to the reduction of aphid performance.
Parasitism Rates of Lysiphlebus testaceipes (Cresson) (Hym.: Aphidiidae) on Schizaphis graminum (Rond.) and Aphis gossypii Glover (Hem.: Aphididae)
Neotropical Entomology , 2001, DOI: 10.1590/S1519-566X2001000400017
Abstract: the objective of the present study was to estimate the rates of parasitism of lysiphlebus testaceipes (cresson) on schizaphis graminum (rond.) and aphis gossypii glover under choice and no-choice condition tests. the experiments were carried out in a controlled environmental chamber at 25±1oc temperature, 70±10% rh, and 12h photophase. second and third instar aphid nymphs were used as hosts and for each colony one less than a day old l. testaceipes female was used. the previously mated and oviposition inexperienced female remained in contact with the hosts for 24 h. in the choice test 10 colonies of s. graminum and 10 colonies of a. gossypii having sections of sorghum leaves as substrate were used. for the no-choice test 10 colonies of s. graminum maintained on sections of sorghum leaves and 10 colonies of a. gossypii maintained on pepper leaves were used. in the choice test the parasitism was 67% and 46% for s. graminum and a. gossypii, respectively whereas in the no-choice test the parasitism was 76% for s. graminum and 56% for a. gossypii. superparasitism was not observed for s. graminum. the aphid s. graminum was the most suitable for multiplication of the parasitoid l. testaceipes under laboratory conditions.
Effect of sodium silicate application on the resistance of wheat plants to the green-aphids Schizaphis graminum (Rond.) (Hemiptera: Aphididae)
Basagli, Marco A.B.;Moraes, Jair C.;Carvalho, Geraldo A.;Ecole, Carvalho C.;Gon?alves-Gervásio, Rita de C.R.;
Neotropical Entomology , 2003, DOI: 10.1590/S1519-566X2003000400017
Abstract: the green-aphid schizaphis graminum (rond.) is considered the major important pest of wheat plant, for causing severe injuries to the plants in all phenological crop stages, being able even to cause plant death. the objective of this study was to evaluate the effects of the application of silicon on the resistance of wheat plants to this pest. the experiments were carried out under greenhouse and laboratory conditions. the greenhouse experiment was conducted in a completely randomized experimental design with two treatments, consisting on silicon application and a control (without silicon application) with 10 replications and without environmental control. the laboratory bioassays were conducted under controlled environmental conditions (25 ± 1°c temperature; 70 ± 10% rh; and 12h photophase), in a randomized block experimental design, with a sub-divided plot scheme. the silicon, in the form of sodium silicate solution at 0.4% sio2 was applied in six doses of 50 ml/pot each, at five-day intervals, being the first application performed five days after emergence of the wheat plats. thirty-five days after plants emergence the following evaluations were performed: a) feeding preference in the laboratory; b) feeding preference in the greenhouse; and c) reproduction and development of the green-aphid. application of sodium silicate reduced preference, longevity, and production of nymphs of the green-aphids s. graminum, thus conferring a resistance to wheat plants against this insect-pest.
Efeito da alternancia de genótipos de sorgo resistente e suscetível na biologia de Schizaphis graminum (Rond.) (Homoptera: Aphididae)
Cruz, Ivan;Vendramim, José D.;
Anais da Sociedade Entomológica do Brasil , 1998, DOI: 10.1590/S0301-80591998000200015
Abstract: the effect of alternating a resistant sorghum (sorghum bicolor) genotype, tx 430 x gr, and a susceptible genotype, br 601 on the biology of the greenbug, schizaphis graminum (rond.) was evaluated at embrapa/national corn and sorghum research center, sete lagoas, mg. biological aspects of s. graminum were evaluated by rearing it continuously on susceptible or on resistant genotypes up to three generations or alternatively after each generation between genotypes. on average it was obtained a pre-reproductive period of 6.7 d and reproductive period of 22.6 d when the insects were reared on the susceptible genotype; on the resistant genotype the values were 7.4 and 15.3 d. the production of nymphs/female was 33.7 and 14.7 on the susceptible and resistant genotypes, respectively.
Tolerancia como mecanismo de resistência de sorgo ao pulg?o-verde, Schizaphis graminum (Rond.) (Homoptera: Aphididae)
Cruz, Ivan;Vendramim, José D.;
Anais da Sociedade Entomológica do Brasil , 1998, DOI: 10.1590/S0301-80591998000100018
Abstract: twenty-eight sorghum (sorghum bicolor) resistant genotypes were selected to study the tolerance as the mechanism of resistance to the greenbug, schizaphis graminum (rond.). the genotypes were planted in pots at the embrapa/national corn and sorghum research center, sete lagoas, mg, and individually infested 11-d after planting. twenty-five greenbug adults/plant were mantained during all the test period. the evaluation was based on the difference of growth rate between infested and non-infested plants. thirty-five days after infestation the relative growth of infested plants of tolerant genotypes e redlan a, p 8199 and tx 2567 was 84.4, 85.8 and 84.0%, respectively. this value was 59.7% for infested plants of susceptible genotype br 601.
Determina??o do período de avalia??o de n?o-preferência de sorgo ao pulg?o-verde, Schizaphis graminum (Rond.) (Homoptera: Aphididae)
Cruz, Ivan;Vendramim, José D.;Oliveira, Ant?nio C.;
Anais da Sociedade Entomológica do Brasil , 1998, DOI: 10.1590/S0301-80591998000200018
Abstract: to determine the evaluation period of preference of the greenbug, schizaphis graminum (rond.) to sorghum (sorghum bicolor) genotypes, a study was conducted at the embrapa/national corn and sorghum research center, sete lagoas, mg, using different sources of resistance. cultivars were randomized within pots and 11-d after planting five apterous adult greenbugs/plant were released in the center of the pot. evaluations based on the number of insects in each genotype, after 24, 48, 72 and 96 hours of the insects release indicated that 72 hours after infestation was the ideal period to evaluate the non-preference of s. graminum to sorghum.
Efeito do silício na resistência do sorgo (Sorghum bicolor) ao pulg?o-verde Schizaphis graminum (Rond.) (Homoptera: Aphididae)
Carvalho, Sérgio P.;Moraes, Jair C.;Carvalho, Janice G.;
Anais da Sociedade Entomológica do Brasil , 1999, DOI: 10.1590/S0301-80591999000300017
Abstract: the objetive was to evaluate the effect of silicon as a resistence inducer of sorghum plant to the greenbug schizaphis graminum (rond.). preference tests were conducted using two sorghum genotypes, a suscetible and a resistent one, with and without silicon application. in a free choice test, the adult aphids were released into the center of an arena made up of four leaf disks. in a no choice test, the aphids were confined on sections of leaves. the silicon affected both by reducing the preference and reproduction of the greenbug.
Resposta funcional de Scymnus (Pullus) argentinicus (Weise) (Coleoptera: Coccinellidae) a diferentes densidades do pulg?o verde Schizaphis graminum (Rond. ) (Homoptera: Aphididae)
Vieira, Gilvania F.;Bueno, Vanda H. P.;Auad, Alexander M.;
Anais da Sociedade Entomológica do Brasil , 1997, DOI: 10.1590/S0301-80591997000300012
Abstract: the functional response, search time and handling time of the predator scymnus (pullus) argentinicus (weise) were evaluated. nymphs of 3rdand 4th instars of the greenbug, schizaphis graminum (rond.), were provided as food. the statistical design was randomly in a factorial 3 x 5, with three densities of the greenbug (10, 25, 35 nymphs) and four instars and adult of the predator, in 10 replications. tests were conducted in an environmental chamber at 25± 1oc, 70± 10% rh and 14 hours photophase. for both larvae and adults of s. (pullus) argentinicus the amount of predated nymphs increased with the increment of aphid densities, until reaching a plateau (functional response type ii). predation in the 4th instar was higher and greater for the density of 35 nymphs compared to the densities of 10 and 25 nymphs. the increment in predation increased, from density 10 to 25, but decreased at density 25 to 35 nymphs. the search time incresead gradually with the age of the predator, while the handling time decreased with the age. adult females presented higher predation and searched faster for prey than males. searching time decreased with the increase in aphid density.
Evaluación de la resistencia a Schizaphis graminum (Hemiptera: Aphididae) en cebada Assessment of resistance against Schizaphis graminum (Hemiptera: Aphididae) in barley  [cached]
Erica F. Tocho,Ana M. Marino de Remes Lenicov,Ana M. Castro
Revista de la Sociedad Entomol?3gica Argentina , 2012,
Abstract: El pulgón verde de los cereales, Schizaphis graminum (Rondani), es una de las principales plagas de estos cultivos en el mundo y también presente en Argentina. Si bien el control químico es la práctica más utilizada, el uso de variedades resistentes (uno de los componentes principales del MIP) es la estrategia más efectiva y ambientalmente más amigable para el control de plagas. Dado que las plantas presentan distintos mecanismos que les permiten defenderse de los insectos, el objetivo de este trabajo fue caracterizar la resistencia a Schizaphis graminum en una población de líneas recombinantes de cebada, e identificar aquellas con mejores características, portadoras de genes de resistencia a este insecto. La antixenosis fue analizada por la prueba de libre selección de hospederos. La antibiosis se evaluó por los parámetros del ciclo y el desarrollo del áfido y la tolerancia por características de crecimiento de las plantas bajo infestación. Al menos ocho líneas antibióticas fueron más tolerantes que sus testigos, presentando similares pesos secos, área foliar y contenido de clorofila bajo infestación. Estas líneas portadoras de genes de resistencia pueden ser de utilidad en los planes de mejora de la cebada. Greenbug, Schizaphis graminum (Rondani) is one of the major pests of cereals around the world that is present in Argentina. Chemical control is the most widely used practice; however, the use of resistant varieties, one of the main components in IPM, is the most effective and environmentally sustainable strategy of control. Since plants have different types of insect resistance that allow them to defend against pests, the aim of the current study was to characterize the resistance to Schizaphis graminum in a population of recombinant inbred lines of barley and to identify lines with improved characteristics that enable the development of commercial cultivars. Antixenosis was studied by the host free choice test. Antibiosis was assessed by means of aphid life cycle and developmental traits. Tolerance mechanism was analyzed by plant growth parameters. At least eight lines carrying antibiosis were more tolerant than their controls, with similar dry weight, leaf area and chlorophyll contents, under infestation. These lines could provide resistance genes against this aphid pest and would be useful in plant breeding programs.
Chromosome studies in southern Brazilian wheat pest aphids Sitobion avenae, Schizaphis graminum, and Methopolophium dirhodum (Homoptera: Aphididae)
Celis, Verónica E. Rubín de;Gassen, Dirceu N.;Santos-Colares, Marisa C.;Oliveira, Alice K.;Valente, Vera L.S.;
Brazilian Journal of Genetics , 1997, DOI: 10.1590/S0100-84551997000300010
Abstract: we examined the chromosome set of the aphid species sitobion avenae, schizaphis graminum and methopolophium dirhodum by means of conventional staining and c, nor, alui and haeiii banding methods. these species are considered important pests to several plants of economic interest in brazil. no variation was observed in the number of chromosomes of s. avenae, whereas there was intraspecific variation in the other two species. interspecific differences in the response to the banding treatments were observed. whereas these techniques allowed the identification of several s. graminum chromosome pairs, only the alui treatment was capable of inducing differential staining in the m. dirhodum chromosomes and no clear patterns emerged when the s. avenae preparations were treated
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