Neotropical Entomology (2003) 32, 177-181

Eloisa Salmeron and Celso Omoto (2003)
Caracterização da Resistência de Blattella germanica (L.) (Dictyoptera: Blattellidae) a Deltametrina e Clorpirifós e Relações de Resistência Cruzada com Fipronil
[Characterization of deltamethrin and chlorpyirifos resistance in Blattella germanica (L.) (Dictyoptera: Blattellidae) and cross-resistance relationships to fipronil]
Neotropical Entomology 32 (1), 177-181
Abstract: The objectives of this study were to characterize the resistance of Blattella germanica (L.) to deltamethrin and chlorpyrifos and to evaluate their cross-resistance relationships to fipronil. The isolation of resistance was done under laboratory conditions from field-collected populations. Three cycles of selection pressure with deltamethrin and chlorpyrifos were conducted to obtain the Deltamethrin-R and Chlorpyrifos-R strains. The estimated LD₅₀ for the susceptible (SUS) strain was 0.24 (IC 95% 0.18-0.31) and for Deltamethrin-R strain was 10.26 (IC 95% 7.28 - 14.17) µg deltamethrine/mg. For chlorpyrifos, LD₅₀ for the SUS strain was 4.16 (IC 95% 2.80 - 5.33) and for Chlorpyrifos-R strain was 24.98 (IC 95% 20.90-30.28) µg chlorpyrifos/mg. Therefore, the resistance ratios were approximately 43- and 6-fold to deltamethrin and chlorpyrifos, respectively. A low intensity of cross-resistance (approximately 2-fold) was observed between fipronil and the insecticides deltamethrin and chlorpyrifos. Thus, fipronil can be used as a good candidate in resistance management programs of B. germanica to deltamethrin and chlorpyrifos.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Database assignments for author(s): Celso Omoto

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Blattella germanica