Susceptibility of four field populations of the diamondback moth Plutella xylostella L. (Lepidoptera: Yponomeutidae) to six insecticides in the Sydney region, New South Wales, Australia

Abstract

Concerns about the failure of insecticides to control the diamondback moth (DBM) Plutella xylostella in the Sydney region of New South Wales, Australia, necessitated the current investigation to establish the susceptibility of four field populations of the DBM to six insecticides. These include two each of organophosphates (OPs), and synthetic pyrethroid insecticides as well as two new products with different modes of action, spinosad and indoxacarb, currently recommended for DBM control in the region. Topical application of the insecticides to the third-instar larvae showed high resistance to pyrethroids (permethrin and esfenvalerate) of 35.0-to 490.0-fold. Resistance to the OPs (methamidophos and chlorpyrifos) and indoxacarb ranged from 12.1-to 36.2-fold and from 11.4-to 34.6-fold, respectively. However, the field populations were susceptible to spinosad (resistance factors only twoto threefold compared with the susceptible strain). A 2 h pre-treatment of the esfenvalerate-resistant strain with the synergists piperonyl butoxide and diethyl maleate increased the toxicity of esfenvalerate by 30.0-and 1.9-fold, respectively, suggesting the involvement of esterases and/or monooxygenases as the key mechanism(s) of insecticide resistance with glutathione S-transferases playing a minor role.

Resistance of Brazilian diamondback moth populations to insecticides

“…Eziah et al (2008) verified that Australian field populations of P. xylostella were susceptible to spinosad. In the present study, although five populations had toxicity ratios to spinosad (2.3 -to 5.1 -fold), both field and laboratory populations sur- Chi Square (p > 0.05).…”

Biochemical mechanism of chlorantraniliprole resistance in Spodoptera litura (Fab) (Lepidoptera: Noctuidae)

“…Sial et al (2011d) suggested enhanced esterase activity is responsible for the resistance to chlorantraniliprole in C. rosaceana. Enhanced activity of GST sand MFO enzymes has been found to be related to pyrethroid, organophosphate resistance (Eziah et al, 2008;Ashraf et al, 2010;Tang et al, 2011). Di et al (2014) reported that detoxification by mixed-function oxidase and glutathione S-transferases might be involved in chlorantraniliprole resistance in P. xylostella.…”

Sublethal effects of indoxacarb on the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae)

“…The results obtained from this bioassay indicated that indoxacarb is also toxic to P. xylostella collected in Tehran. Toxicity of indoxacarb on P. xylostella was reported by Eziah et al (2008). Sayyed et al (2005) tested the effect of several insecticides, including indoxacarb, on a number of generations of P. xylostella in the laboratory, and LC 50 values were estimated as 40 and 3 lg L -1 for the 2nd and 8th generations, respectively.…”