Relação entre a atividade de esterases e a resistência de Myzus persicae (Sulz.) (Sternorrhyncha:Aphididae) a pirimicarbe

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 Piraí 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 LC 50 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 LC 50 and the frequency of R2 forms and a significant negative correlation between LC 50 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.

Insecticidal activity of citronella grass essential oil on Frankliniella schultzei and Myzus persicae

“…As a result of the emergence of resistant populations (FURIATTI;LAZZARI, 2003;LUOGEN et al, 2005;DOÐRAMACI;TINGEY, 2008), demand has increased for agricultural pest control methods that offer safety to humans, selectivity to natural enemies, biodegradability, economic viability and low environmental impact (VIEGAS, 2003).…”

Variability of esterase patterns in adult flies of the saltans species group of Drosophila (subgenus Sophophora)

“…Esterases are enzymes that play important physiological roles. In insects they are involved in the neuronal activity (Harel et al 2000), in the metabolism of juvenile hormone (Gu and Zera 1994;Furiatti and Lazzari 2003;Wogulis et al 2006), in reproduction (Richmond and Senior 1991;Mikhailov and Torrado 2000;Odgers et al 2002), digestion (Kapin and Ahmad 1980;Kerlin and Hugues 1992;Argentine and James 1995;Kozaric et al 2006) and in the resistance to insecticides (Feyereisen 1995;Wang et al 2004;Gupta et al 2005;Cui et al 2006), among others. Such important roles justify the interest of knowing how species in a group differ as to the esterase patterns.…”