The use of substituted alkynyl phenoxy derivatives of piperonyl butoxide to control insecticide‐resistant pests

Abstract

These 'second-generation' synergists could overcome metabolic resistance in many pest species and possibly enable reduced rates of insecticide application in some cases. © 2016 Society of Chemical Industry.

The interactions of piperonyl butoxide and analogues with the metabolic enzymes FE4 and CYP6CY3 of the green peach aphidMyzus persicae(Hemiptera: Aphididae)

“…These findings are in line with previous data reported for the inhibition of O-deethylation activity in two pyrethroid-resistant populations of M. aeneus, owing to the enhanced P450 CYP6BQ23, and the synergistic factors obtained with full dose-response bioassays against a neonicotinoid-resistant population of M. persicae: in both cases, the most potent inhibitors were benzodioxole derivatives with an alkynyl group in the side chain. 7 Similar results were also obtained previously in in vivo trials with resistant houseflies. 28,29 Finally, a comparison between analogues 13 (no alkyl chain) and 14 (propyl alkyn chain) demonstrated a higher synergistic factor of the former compound in bioassays against M. persicae and M. aeneus.…”

“…Similarly, high levels of E4 together with enhanced P450 activity resulted in a 60-fold resistance to imidacloprid in a clone of aphids from Greece, a resistance that was substantially reduced by pretreatment with PBO and abolished by pretreatment with the alkynyl analogue EN 1-126. 7,27 No assays have been performed previously to characterise directly the interactions between PBO/analogues and CYP6CY3 from M. persicae. This P450 has been shown to be involved in insecticide detoxification 13 and is capable of metabolising nicotine and two neonicotinoids (imidacloprid and clothianidin) into less toxic metabolites.…”

“…The presence of a sodium carboxylate (−COONa) group at the end of the polyether chain (11) and the replacement of the side chain with a carboxyl group (7) or with a dodecyl chain (10) resulted in a significant reduction in binding affinity, and replacement with a butynyloxy chain reduced the inhibition when compared with its counterpart (8 < 4; 9 < PBO). Analogue 20, with a foreshortened polyether chain, had a slightly higher affinity than its counterpart 17.…”

“…The higher in vitro potency of the alkynyl phenoxy analogues was also reflected in vivo, enabling higher mortality of pyrethroid-resistant pollen beetle in bioassays. 7 Based on the reported biochemical mechanism of PBO, a range of existing analogues have been explored and evaluated for their inhibition efficacy against detoxifying enzymes derived from green peach aphid, Myzus persicae (Sulzer), one of the most economically important crop pests worldwide. 8 This pest has evolved high levels of resistance to almost all classes of insecticide, including, in the last few years, neonicotinoids.…”

“…13 Previous studies have elucidated the interactions of PBO and analogues with the resistance-associated esterase E4, 14 and an alkynyl phenoxy analogue (EN 1-126) was also found to give higher synergism factors than PBO against an imidacloprid-resistant strain of green peach aphid in laboratory bioassays. 7 The present study investigated the interactions of both phase 1 detoxifying enzymes FE4 and CYP6CY3 with PBO or existing PBO analogues. The resultant structure-activity relationships were then used to design novel structures with higher efficacy that could be used in future insecticide formulations for agricultural applications.…”