Programa de Pós-graduação em Agronomia
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Navegando Programa de Pós-graduação em Agronomia por Por Orientador "Barrigossi, José Alexandre Freitas"
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Item Resistência a inseticidas em populações de percevejo-do-colmo do arroz Tibraca limbativentris (hemiptera: pentatomidae)(Universidade Federal de Goiás, 2016-09-13) Maciel, Diogo Nery; Fragoso, Daniel de Brito; http://lattes.cnpq.br/4162628180188621; Barrigossi, José Alexandre Freitas; http://lattes.cnpq.br/5377957113836597; Barrigossi, José Alexandre de Freitas; Fragoso, Daniel de Brito; Aguiar, Raimundo Wagner de Souza; Araújo, Leila Garcês deThe increase in insecticide application for control the rice stalk stink bug Tibraca limbativentris Stal (Hemiptera: Pentatomidae) in irrigated rice in Brazil, has been reported by producers as responsible for loss of effectiveness of some insecticides commonly used to manage this insect and this is the base of this investigation. The insecticides used in this study were: bifenthrin, carbosulfan, etophenprox, λ-cyhalothrin, and thiametoxam. Six populations of insects were collected in producing areas of the states of Tocantins, Goiás and Santa Catarina, Brazil. Insect adults of each population were submitted to discriminant concentrations (LC95s) previously determined for the population collected in natural habitat in Santo Antônio de Goiás, and used as standard susceptible population. The frequency of individuals resistant in the population of Formoso do Araguaia was 76% for carbosulfan, 86% for bifenthrin, 72% for etofenprox, 80% for L-cyalothrin, and 80% for thyamethoxam. Although the frequencies of resistant individuals can be considered low to moderate, it is first report of resistance of T. limbativentris to insecticides. These results indicate the resistance development to other insecticides with different mode of actions, with emphasis to the stink bug populations of Formoso do Araguaia-TO. These results also indicates a possible occurrence of crossed a resistance or multiple in that population.Item Diversidade genética e estrutura populacional de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) nas culturas do arroz (Oryza sativa L.) e cana-de-açucar (Saccharum officinarum L.)(Universidade Federal de Goiás, 2015-03-25) Nascimento, Jacqueline Barbosa; Abreu, Aluana Gonçalves de; Barrigossi, José Alexandre Freitas; http://lattes.cnpq.br/5377957113836597; Barrigossi, José Alexandre Freitas; Fernandes, Paulo Marçal; Albernaz, Karina Cordeiro; Borga, Tereza Cristina de Oliveira; Hirose, EdsonThe change in composition of the host-plants in the agricultural landscape can generate enough divergent natural selection to allow ecological adaptation that leads to specialization and subsequently to speciation in species of insect. The objective of this study was to determine the diversity of genetic and population structures of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae), which was collected in two hostplants using microsatellite markers. Samples of larvae of this stem borer were collected on rice and sugarcane in different fields during the harvest of 2012/2013 in the states of Tocantins, Goiás, Mato Grosso, Mato Grosso do Sul, and Rio Grande do Sul. A total of 127 alleles were found distributed among the eight loci in seventeen populations, with a total of 426 individuals. The loci were highly polymorphic, with average of 15,87 alleles. The expected heterozygosity (HE) and observed (HO) were 0,579 and 0,350, respectively. A lower total number of alleles (35) was found in population of Morrinhos, as opposed to Formoso do Araguaia which has the largest (62). The same way, the smallest and the largest average number of alleles per locus (Am) were observed in these populations (4,38 and 7,75). The population from the Formoso do Araguaia showed the highest value for the allelic richness (6,82). In all populations, the observed heterozygosity (HO) was lower than expected (HE). The average polymorphic information content (PIC) in populations of D. saccharalis was 0,530. The intrapopulational fixation indexes (f) estimated for each population showed positive values and significantly different from zero with a average value of 0,403. The coefficient of inbreeding species was 0,399. The estimates FIT and FST (θ) values were 0,437 and 0,062 respectively. These global estimates indicated that there is genetic structure among these populations. Despite global estimates had indicated genetic structure, the structuring (θ) among of populations of the sugarcane was not significant; in contrast with the populations of the rice which showed θ values significant. There was a significant correlation between genetic and geographic distances estimated using the Mantel’s test (r=0,76; p= 0,0033), in which there is an increase in pattern of genetic distance with the increase of geographic distance in cluster analysis and population structures observed with the formation of the two groups of populations. The first was formed by populations from the state of Goiás and the second was composed of populations of Mato Grosso, Mato Grosso do Sul and Rio Grande do Sul. The population of Formoso do Araguaia sampled in rice showed in an intermediate position to the two groups formed. These results indicate that the genetic diversity of D. saccharalis is structured in space and the plant-host, in this study, did not have a key role in the process of genetic divergence populations.Item Influência de semioquímicos emitidos por plantas de arroz no comportamento de Tibraca limbativentris, Glyphepomis spinosa (Heteroptera: Pentatomidae) e Telenomus podisi (Hymenoptera: platygastridae)(Universidade Federal de Goiás, 2018-04-18) Ulhoa, Lucas Adjuto; Moraes, Maria Carolina Blassioli; http://lattes.cnpq.br/6269532115803649; Barrigossi, José Alexandre Freitas; http://lattes.cnpq.br/5377957113836597; Barrigossi, José Alexandre Freitas; Magalhães, Diego Martins; Laumann, Raul AlbertoTibraca limbativentris Stål is one of the stink bugs most harmful to rice cultivation in Brazil, mainly in irrigated environment. Glyphepomis spinosa Campos & Grazia is a stink bug of secondary economic importance, but often occurs in rice fields in the Midwestern and Northern regions of Brazil. To defend against these stink bugs, plants can emit volatile organic compounds that act directly as repellent or as toxic substances, or indirectly, by attracting natural enemies. Studies on chemical communication between insects and plants are fundamental to understand the host searching process, and can be used to manage insect pests and natural enemies in the field. The objectives of this work were to identify the constitutive and herbivore - induced volatile organic compounds emitted by rice and to evaluate the influence of these volatiles on the searching behavior of the stink bugs T. limbativentris and G. spinosa and their natural enemy, the egg parasitoid Telenomus podisi Ashmead. The volatiles were collected from rice (BRS Pampa) without injury and with injury imposed by two virgin females (adults) of T. limbativentris and G. spinosa, for up to 144 hours. The samples were analyzed by gas chromatography coupled to a flame ionization detector (CG-FID) and gas chromatography coupled to mass spectrometry (GC-MS). The responses of virgin and mated females of T. limbativentris and G. spinosa and virgin females of T. podisi were evaluated in a "Y-tube" olfactometer. The rice plants responded to injury producing volatiles, especially the sesquiterpenoids. Virgin females of T. limbativentris preferred heathy plants and air (control without plants) than by injured plants. Virgin females of G. spinosa females preferred air than by injured plants. The egg parasitoids T. podisi preferred injured plants by T. limbativentris than by healthy plants. T. podisi also preferred injured plants by G. spinosa than by air. The results show that rice plants release defense compounds that act directly repelling the stink bugs T. limbativentris and G. spinosa and indirectly attracting the natural enemy T. podisi.