Detection of the A302S Rdl mutation in fipronil bait-selected strains of the German cockroach (Dictyoptera: Blattellidae).
Extensive usage and heavy reliance on insecticides have led to the development of insecticide resistance in the German cockroach, Blattella germanica (L.). Six field-collected strains of B. germanica from Singapore were used to investigate resistance to fipronil and dieldrin. The three strains (Boat Quay, Cavenagh Road, and Ghimmoh Road) with greatest resistance to fipronil were subjected to selection with fipronil bait up to the F5 generation. Synergism assay and molecular detection of a target site mutation were used to elucidate the mechanism of fipronil resistance in these strains. With the exception of the Cavenagh Road strain, all parental strains were susceptible to dieldrin. This strain exhibited resistance to dieldrin and fipronil with resistance ratios of 4.1 and 3.0, respectively. Piperonyl butoxide and S,S,S-tributylphosphorotrithioate were antagonistic toward fipronil toxicity in all strains. Bait selection significantly increased fipronil and dieldrin resistance in the three chosen strains, either in topical bioassay or bait evaluations. There was a significant positive relationship [y = (6,852.69 +/- 1,988.37) x - (708.93 +/- 1,226.28), where x = fipronil toxicity and y = dieldrin toxicity] between dieldrin and fipronil resistance levels, indicating significant cross-resistance between the insecticides. High frequencies of individuals possessing the Rdl gene mutation were found in the F5 generation of the three strains selected with fipronil bait. The synergism assays indicated that monooxygenase and esterase were not involved in fipronil resistance in the strains studied herein. The A302S Rdl mutation was the major mechanism contributing to fipronil and dieldrin resistance in these strains.
Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia.
Ling-Hui
LH
Ang
Wasi Ahmad
WA
Nazni
Meng-Kiat
MK
Kuah
Alexander Chong
AC
Shu-Chien
Chow-Yang
CY
Lee
D000818:Animals; D020048:Blattellidae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D004026:Dieldrin / Q000494:pharmacology*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D009154:Mutation; D009758:Nymph / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D063086:Organothiophosphates / Q000494:pharmacology; D010574:Pesticide Synergists / Q000494:pharmacology; D010882:Piperonyl Butoxide / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology*; D018079:Receptors, GABA / Q000235:genetics / Q000378:metabolism; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
D019476:Insect Proteins; D007306:Insecticides; D063086:Organothiophosphates; D010574:Pesticide Synergists; D011720:Pyrazoles; D018079:Receptors, GABA; C006863:butyl phosphorotrithioate; D004026:Dieldrin; D010882:Piperonyl Butoxide; C082360:fipronil