13 research outputs found

    Tri-trophic Analyses of Rice, the Sugarcane Borer, and Putative Biological Control Agents

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    A three-year field experiment was conducted to evaluate the tolerance and compensatory response of rice (Oryza sativa L.) to injury caused by the sugarcane borer, Diatraea saccharalis (F.). Two mechanisms of within-plant tolerance/compensation were observed. Stem injured plants produced ca. 0.69 more tillers than uninjured plants, while tillers with leaf and leaf sheath injury produced larger panicles, up to 39.5% and 21.0% heavier than uninjured tillers, when injury occurred at 3rd tiller stage and at panicle differentiation, respectively. A 2-year field cage experiment was conducted to determine the biological control potential of Cotesia flavipes (Cameron) against the sugarcane borer on rice. The effective search rate was 49 cm2 ground area (2.2 tillers) parasitoid-1 day-1. A cohortbased age-structured model was developed to simulate the population dynamics and economic value of the sugarcane borer and C. flavipes in rice, as affected by overwintering larval density, timing and rate of parasitoid aerial release, and year-to-year climate (temperature and rainfall). The results suggest C. flavipes was most effective when released during the 1st sugarcane borer generation. The maximum simulated economic benefit (112.05ha1)wasca.7.8control.TheinabilityofC.flavipestoprovideeconomiccontrolintemperatesubtropicalareasisduetoitshighrearingcost,aloweffectivesearchrate,alowmaximumrateofparasitismperfemale,andbothspatialandtemporalasynchronyofparasitoidemergencewiththelarvalhosts.ThebiocontrolcapabilityofTrichogrammagalloiZucchiwasalsosimulated.ThemaximumeconomicbenefitprovidedbyT.galloiwas112.05 ha-1) was ca. 7.8% of that provided by insecticide-based control. The inability of C. flavipes to provide economic control in temperate-subtropical areas is due to its high rearing cost, a low effective search rate, a low maximum rate of parasitism per female, and both spatial and temporal asynchrony of parasitoid emergence with the larval hosts. The biocontrol capability of Trichogramma galloi Zucchi was also simulated. The maximum economic benefit provided by T. galloi was 1128.75 ha-1, ca. 79.0% of that provided by insecticide-based control. Theoretical analyses were conducted to estimate the effectiveness of augmentative releases, using data from previous studies of parasitism of lepidopteran pests by hymenopteran parasitoids with host and parasitoid density as factors. The maximum daily parasitism per female was highest for parasitoids that attack exposed larvae, followed by parasitoids that attack eggs, semi-exposed larvae, and concealed larvae. Simulation analyses were conducted to estimate the population dynamics and economic value of D. saccharalis, herein used as a model host, and each of 5 parasitoid categories (solitary parasitoids that attack eggs, exposed larvae, and semi-exposed larvae, gregarious parasitoids that attack eggs and concealed larvae) in rice, as affected by overwintering larval density, timing of parasitoid release, and year-to-year climate. Among the 13,500 simulations that were conducted, 480 (3.6%) provided a greater economic value than insecticide-based control. All 480 simulations were obtained using solitary parasitoids that attack exposed or semi-exposed larvae. Solitary egg parasitoids provided an average of 42.2% of the economic value provided by insecticide-based control when released 30 days after planting. Gregarious parasitoids that attack eggs or concealed larvae provided almost no positive economic benefit. For parasitoid species that do not overwinter successfully in areas where they are released or that exhibit temporal or spatial asynchrony with their host early in the spring, our results suggest augmentative biological control is only effective for solitary parasitoids that attack either exposed or semi-exposed larvae, with current rearing, shipping and release costs

    A two-agent model applied to the biological control of the sugarcane borer (Diatraea saccharalis) by the egg parasitoid Trichogramma galloi and the larvae parasitoid Cotesia flavipes

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    The paper is aimed at a methodological development in biological pest control. The considered one pest two-agent system is modelled as a verticum-type system. Originally, linear verticum-type systems were introduced by one of the authors for modelling certain industrial systems. These systems are hierarchically composed of linear subsystems such that a part of the state variables of each subsystem affect the dynamics ofthe next subsystem. Recently, verticum-type system models have been applied to population ecology as well, which required the extension of the concept a verticum-type system to the nonlinear case. In the present paper the general concepts and technics of nonlinear verticum-type control systems are used to obtain biological control strategies in a two-agent system. For the illustration of this verticumtype control, these tools of mathematical systems theory are applied to a dynamic model of interactions between the egg and larvae populations of the sugarcane borer (Diatraea saccharalis) and its parasitoids: the egg parasitoid Trichogramma galloi and the larvae parasitoid Cotesia flavipes. In this application a key role is played by the concept of controllability, which means that it is possible to steer the system to an equilibrium in given time. In addition to a usual linearization, the basic idea is a decomposition of the control of the whole system into the control of the subsystems, making use of the verticum structure of the population system. The main aim of this study is to show several advantages of the verticum (or decomposition) approach over the classical control theoretical model (without decomposition). For example, in the case of verticum control the pest larval density decreases below the critical threshold value much quicker than without decomposition. Furthermore, it is also shown that the verticum approach may be better even in terms of cost effectiveness. The presented optimal control methodology also turned out to be an efficient tool for the “in silico” analysis of the cost-effectiveness of different biocontrol strategies, e.g. by answering the question how far it is cost-effective to speed up the reduction of the pest larvae density, or along which trajectory this reduction should be carried out

    Screening test of Diatomaceous Earth as an alternative control method for Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) eggs

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    The sugarcane borer Diatraea saccharalis is a pest that causes damage to sugarcane fields. The female lays imbricated egg masses on the leave. They cause the greatest damage as larvae, and thus, control before egg hatching is desired to prevent the development of this pest and avoid damage to the plant. Diatomaceous Earth, or diatomite, is inert dust with insecticidal properties. In this work, we aimed to test the activity of Diatomaceous Earth on viable eggs of D. saccharalis as a potential alternative control method for sugarcane borer. D. saccharalis eggs 1 day after oviposition were immersed in a Diatomaceous Earth solution (10% - w/v) for 5, 10, or 15 min and observed every 24 h for 216 h of analysis. During the first 72 h, there were no changes observed in egg morphology, which maintained an oval shape, pale yellow in color. After 96 h, chorion striations were observed in the treatments with 10 and 15 min of exposure and were not present in the chorion controls eggs. Differences between embryo's number it was observed after 96h in the 15 min treatment when compared with the untreated eggs control. Besides that, control larvae completely hatched in 192 h and the treatment with 10 min and 15 min not shown completely hatching suggesting a delay in the embryonic development of the D. saccharalis larvae. Overall, our study is the first report of the application of D. saccharalis eggs, and we believe that Diatomaceous Earth could be a potential tool for the control of Diatraea eggs, however, thorough investigations are required to elucidate the action of this powder on Diatraea and would be an alternative method to interrupt the biological cycle of the pest

    Screening test of Diatomaceous Earth as an alternative control method for Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) eggs

    Get PDF
    The sugarcane borer Diatraea saccharalis is a pest that causes damage to sugarcane fields. The female lays imbricated egg masses on the leave. They cause the greatest damage as larvae, and thus, control before egg hatching is desired to prevent the development of this pest and avoid damage to the plant. Diatomaceous Earth, or diatomite, is inert dust with insecticidal properties. In this work, we aimed to test the activity of Diatomaceous Earth on viable eggs of D. saccharalis as a potential alternative control method for sugarcane borer. D. saccharalis eggs 1 day after oviposition were immersed in a Diatomaceous Earth solution (10% - w/v) for 5, 10, or 15 min and observed every 24 h for 216 h of analysis. During the first 72 h, there were no changes observed in egg morphology, which maintained an oval shape, pale yellow in color. After 96 h, chorion striations were observed in the treatments with 10 and 15 min of exposure and were not present in the chorion controls eggs. Differences between embryo’s number it was observed after 96h in the 15 min treatment when compared with the untreated eggs control. Besides that, control larvae completely hatched in 192 h and the treatment with 10 min and 15 min not shown completely hatching suggesting a delay in the embryonic development of the D. saccharalis larvae. Overall, our study is the first report of the application of D. saccharalis eggs, and we believe that Diatomaceous Earth could be a potential tool for the control of Diatraea eggs, however, thorough investigations are required to elucidate the action of this powder on Diatraea and would be an alternative method to interrupt the biological cycle of the pest

    Small-scale rearing of Anagasta kuehniella for Trichogramma production

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    This book contains 4 chapters focusing on techniques for small-scale rearing of the egg parasitoids Trichogramma spp. in the factitious host Anagasta kuehniella [Ephestia kuehniella]. These parasitoids are among the most widely used natural enemies in the world, and in Brazil are used to control lepidopteran pests in a wide variety of crops.illustrato

    Management Practices for Insect Resistance in Bt Maize

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    The failure to reduce the population of a phytophagous species recognized as a key pest in a given situation usually occurs by not using the principles of Integrated Pest Management (IPM). The control of insect pests in agriculture has been done mainly through the application of chemical insecticides. However, chemical insecticides has lost effectiveness due to the selection of populations of resistant insects and cause adverse environmental effects. The main resistance management programs (IRM) strategy is the use of ‘high dose/refuge’, which involves the use of high dose of Bt protein in plants, promoting high mortality of heterozygotes associated with the planting of refuge, ie, a proportion of the crop in which it must be planted a non-Bt variety, allowing the survival of susceptible individuals. The emergence of Bt crops is an important step between the tactics available for pest control in various crops such as maize, canola, cotton and, in the near future, soybeans

    BENEFICIAL INSECTS IN GREENHOUSES: A STUDY OF SOME ASPECTS OF CANNIBALISM AND POLLINATION.

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    Tesis doctoral en período de exposición públicaDoctorado en Ciencias Aplicadas al Medio Ambiente (RD99/11) (8904

    XXVI Congresso Brasileiro de Entomologia ; IX Congresso Latino-Americano de Entomologia: anais...

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    O Congresso Brasileiro de Entomologia (CBE) é um evento promovido a cada dois anos pela Sociedade Entomológica do Brasil, e que tem se consolidado ao longo dos anos como um dos principais eventos entomológicos do mundo. Nesta XXVI edição, realizada em Maceió, AL, pela Empresa Brasileira de Pesquisa Agropecuária (Embrapa), o CBE aconteceu simultaneamente ao IX Congresso Latino-americano de Entomologia (IX CLE). O XXVI CBE / IX CLE teve como objetivo propiciar um espaço amplo para discussões e intercâmbio de informações nas mais diversas áreas da Entomologia básica e aplicada, entre profissionais, empreendedores, produtores e, principalmente estudantes, de toda a América Latina, bem como de outros países, contribuindo assim para o desenvolvimento da Entomologia em nível mundial. Durante os cinco dias do evento, Maceió foi a casa dos principais entomologistas do continente. Nesta obra, são apresentados os resumos de 95 palestras, 110 apresentações orais, e 1.0 07 trabalhos apresentados na forma de pôster durante o XXVI CBE / IX CLE, estes divididos nas 22 áreas temáticas do evento: Biologia, Fisiologia e Morfologia; Ecologia e Biodiversidade; Polinização; Controle biológico com vírus entomopatogênicos; Controle biológico com fungos entomopatogênicos; Controle biológico com bactérias entomopatogênicas; Controle biológico com nematoides entomopatogênicos; Controle biológico com predadores; Controle biológico com parasitoides; Controle químico; Semioquímicos e Comportamento; Plantas inseticidas; Entomologia médica e veterinária; Entomologia forense; Entomologia florestal; Pragas quarentenárias; Resistência de plantas a insetos; Manejo integrado de pragas; Educação e Etnoentomologia; Organismos geneticamente modificados; Ácaros; e Sistemática e Taxonomia. Queremos expressar nosso mais sincero agradecimento a todos os patrocinadores, apoiadores, diretoria e conselho deliberativo da SEB, Embrapa, membros da comissão organizadora, avaliadores de trabalhos, voluntários, coordenadores de mesas-redondas, palestrantes, congressistas, e a todos os que direta ou indiretamente colaboraram para a realização do evento, e tornaram possível a publicação desta obra. Salientamos que as opiniões manifestadas nos resumos são de inteira responsabilidade dos seus autores, não necessariamente refletindo o pensamento dos editores. Desejamos a todos uma boa leitura, e que desfrutem desta obra.Editores Técnicos: Elio Cesar Guzzo; Marcus Vinicius Sampaio; Jader Braga Maia ; Aldomário Santo Negrisoli Junior
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