Metabolic mechanisms of insecticide resistance in the western flower thrips, Frankliniella occidentalis (Pergande)

Abstract

The interactions between six insecticides (methiocarb, formetanate, acrinathrin, deltamethrin, methamidophos and endosulfan) and three potential synergists (piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by topical exposure in strains selected for resistance to each insecticide, and in a susceptible strain of Frankliniella occidentalis (Pergande). In the susceptible strain PBO produced appreciable synergism only of formetanate, methiocarb and methamidophos. Except for endosulfan, PBO synergized all the insecticides to varying degrees in the resistant strains. A very high level of synergism by PBO was found with acrinathrin, which reduced the resistance level from 3344- to 36-fold. PBO slightly synergized the carbamates formetanate (4.6-fold) and methiocarb (3.3-fold). PBO also produced a high synergism of deltamethrin (12.5-fold) and methamidophos (14.3-fold) and completely restored susceptibility to both insecticides. DEF did not produce synergism with any insecticide in the resistant strains and DEM was slightly synergistic to endosulfan (3-fold). These studies indicate that an enhanced detoxification, mediated by cytochrome P-450 monooxygenases, is the major mechanism imparting resistance to different insecticides in F occidentalis. Implications of different mechanisms in insecticide resistance in F occidentalis are discussed.

Sinérgico alternativo para inseticidas inibidores de acetilcolinesterase

“…Na avaliação de outros inseticidas organofosforados, como o Metamidofós, os valores de FS nas combinações com o PBO variaram de 7,9 a 14,3 (ESPINOSA et al, 2005) e para o Diclorvós de 0,9 a 1,4 (BERNARD et al, 1993). Isso demonstra que o OEPA, avaliado como sinérgico de organofosforados, é promissor, uma vez que algumas combinações de doses e concentrações com os inseticidas desse grupo apresentaram FS acima dos relatados anteriormente (máximo de 33,8 para a Fenitrotiona).…”

Management Strategies for Western Flower Thrips and the Role of Insecticides

“…Likewise, pyrethroids are no longer recommended for use in Turkish greenhouses because of the rapid development of resistance and cross resistance to other chemicals (Dağlı & Tunç, 2008). Resistance to pyrethroids is primarily derived from metabolic detoxification pathways (Broadbent & Pree, 1997;Espinosa et al, 2005;Maymó et al, 2006;Zhao et al, 1995). A broad range of enzymatic detoxification pathways to detoxify pyrethroids have been identified, including cytochrome P450 monooxygenases, glutathione S-transferases and esterases.…”

Benzoylurea resistance in western flower thrips <i>Frankliniella occidentalis</i> (Thysanoptera: Thripidae): the presence of a point mutation in <i>chitin synthase 1</i>

“…In various species of thrips, including F. occidentalis, resistance against major insecticides has been reported, and metabolic detoxification is often involved in enhanced insecticide resistance. 1) For example, cytochrome P450 monooxygenases are reported to be involved in resistance against organophosphates, 2,3) carbamates, 2,4) pyrethroids, 2,3) and neonicotinoids 5) in F. occidentalis [reviewed in 1,6) ]. In addition, point mutations at target sites have been reported: for example, a nonsynonymous substitution in the nicotinic acetylcholine receptor (nAChR) has been identified in spinosad-resistant strains of F. occidentalis 7) and in the melon thrips, Thrips palmi.…”