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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Resistência de populações pernambucanas de traças-das-crucíferas, Plutella xylostella (L.,1758) (Lepidoptera : Plutellidae) a inseticidas / Resistance of Diamonback moth, Plutella xylostella (L.,1758) (Lepidoptera : Plutellidae) populations from Pernambuco state to insecticides

SANTOS, Vanessa Corrêa 01 February 2010 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-12-01T11:35:30Z No. of bitstreams: 1 Vanessa Correa Santos.pdf: 426382 bytes, checksum: 7f2a707e64c6b920d1e709bfb3336891 (MD5) / Made available in DSpace on 2016-12-01T11:35:30Z (GMT). No. of bitstreams: 1 Vanessa Correa Santos.pdf: 426382 bytes, checksum: 7f2a707e64c6b920d1e709bfb3336891 (MD5) Previous issue date: 2010-02-01 / Plutella xylostella (L.) (Lepidoptera: Plutellidae), popularly known as diamondback moth, is a major pest of brassicaceae crops (e.g., kale, cauliflower, broccoli, and cabbage) throughout the world. Several insecticides have been intensively used during several cultivation cycles and, even in some areas, up to 15 to 20 applications per season have been observed. Besides the problems they may cause to human and environmental health, the frequent use of these products has been associated to the evolution of resistance in P. xylostella populations to various insecticides such as the pyrethroids, carbamates, organophosphates, and even Bacillus thuringiensis. The current study objective was to identify the resistance in P. xylostella populations from Pernambuco State, when exposed to abamectin, methomyl, lufenuron, indoxacarb, and diafentiuron. Concentration-response regressions were established using 2nd-instar larvae of P. xylostella. All P. xylostella populations showed significant resistance ratio (RR) to at least one insecticide. The smallestCL50s values were estimated for abamectin, which varied from 0.01 to 0.74 mg/L and the highest CL50s were estimated for diafentiuron, which varied from 47.9 to 122.2 mg/L. The Bezerro County population presented the highest resistance ratios to indoxacarb (25.3-fold), abamectin (61.7-fold), and lufenuron (705.2-fold), compared to the reference population. TheBonito and Jupi Counties populations were 33.0- and 12.0-times more resistant to lufenuron and abamectina, respectively. These results demonstrate that intensive and indiscriminate use of insecticides in Pernambuco must be a concern, which suggests the immediate establishment of a resistance management program associated to integrated pest management in these areas. / Plutella xylostella (L.) (Lepidoptera: Plutellidae), conhecida popularmente como traça-das-crucíferas é considerada a principal praga do cultivo de brássicas (ex: couve, couve-flor, brócolis e repolho) em todo o mundo. Diversos inseticidas têm sido utilizados intensivamente durante o ciclo da cultura, e em algumas áreas já foram detectadas 15 a 20 aplicações por ciclo. Além dos problemas gerados à saúde do agricultor e ao meio ambiente, o uso excessivo desses produtos tem proporcionado o aparecimento de populações resistentes deste inseto-praga a diversos compostos químicos, como é o caso dos inseticidas piretróides, carbamatos, organofosforados e Bacillus thuringiensis. O presente estudo teve como objetivo identificar a resistência em populações de P. xylostella do Estado de Pernambuco, utilizando os inseticidas abamectina, metomil, lufenurom, diafentiuron e indoxacarbe. Curvas de concentração-resposta foram estabelecidas usando lagartas de 2º instar de P. xylostella. Todas as populações pernambucanas de P. xylostella apresentaram razão de resistência (RR) significativa a pelomenos um inseticida. As menores CL50s foram registradas para o inseticida abamectina, variando de 0,01 a 0,74 mg/L e as maiores CL50s foram para o inseticida diafentiuron, 47,9 a 122,2 mg/L. A população do município de Bezerros apresentou as maiores razões de resistência 25,3 a indoxacarbe, 61,7 a abamectina e 705,2 a lufenurom, quando comparadas àpopulação suscetível. A população do município de Bonito apresentou uma razão de resistência 33,0 a lufenurom e Jupi 12,0 para abamectina. Estes resultados demonstram que o uso intensivo e indiscriminado de inseticidas na região Agreste de Pernambuco é preocupante, sugerindo o estabelecimento de um programa de manejo da resistência associado ao manejo integrado de pragas nesta área.

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