Neotropical Entomology (2003) 32, 693-697

Rui S. Furiatti and Sonia M.N. Lazzari (2003)
Relação Entre a Atividade de Esterases e a Resistência de Myzus persicae (Sulz.) (Sternorrhyncha: Aphididae) a Pirimicarbe
[Relationship between esterases activity and the resistance of Myzus persicae (Sulz.) (Sternorrhyncha: Aphididae) to pirimicarb]
Neotropical Entomology 32 (4), 693-697
Abstract: The objective of this research was to evaluate the relationship between the total activity of carboxylesterase and the resistance of M. persicae populations to pirimicarb. The aphids were collected on potato plants in Contenda and Piraf do Sul, PR and Ibicoara, BA, Brazil. For the bioassay, five replicates for each concentration were prepared with 10 aphids placed in plastic vials with a fine fabric mesh on the bottom, and dipped into pirimicarb concentrations (%) at 0.0031; 0.0062; 0.0125; 0.025; 0.05, and 0.1 %, during 10 seconds, then dried on filter paper. After 1h inside a 25°C chamber, the aphids were examined under a stereomicroscope, recording the number of dead insects. The carboxylesterase activity was assessed by in vitro colorimetric technique. A simple correlation was established between the results of the LC₅₀ bioassay and the frequency of M. persicae resistant variants. According to the absorbance level, the aphids were classified as variants S; S/R1 (S or R1); R1; R1/R2 (R1 or R2); R2 and R3, respectively susceptible; partially resistant, resistant and highly resistant. It was found a significant positive correlation between the LC₅₀ and the frequency of R2 forms and a significant negative correlation between LC₅₀ and the frequency of S and S/R1 forms. The colorimetric data supported the bioassay results, indicating that the bioassay was precise enough to determine either populations with high frequency of susceptible individuals or population with high proportion of resistant and highly resistant individuals.
(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): Sonia M.N. Lazzari

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.
	Myzus persicae	Potato (Solanum tuberosum)	Brazil (south)