Evidence of Tolerance to Silica-Based Desiccant Dusts in a Pyrethroid-Resistant Strain of Cimex lectularius (Hemiptera: Cimicidae).

David Lilly,Cameron Webb,Stephen Doggett

doi:10.3390/insects7040074

Abstract

Insecticide resistance in bed bugs (Cimex lectularius and Cimex hemipterus) has become widespread, which has necessitated the development of new IPM (Integrated Pest Management) strategies and products for the eradication of infestations. Two promising options are the diatomaceous earth and silica gel-based desiccant dusts, both of which induce dehydration and eventual death upon bed bugs exposed to these products. However, the impact of underlying mechanisms that confer resistance to insecticides, such as cuticle thickening, on the performance of these dusts has yet to be determined. In the present study, two desiccant dusts, CimeXa Insecticide Dust (silica gel) and Bed Bug Killer Powder (diatomaceous earth) were evaluated against two strains of C. lectularius; one highly pyrethroid-resistant and one insecticide-susceptible. Label-rate doses of both products produced 100% mortality in both strains, albeit over dissimilar time-frames (3–4 days with CimeXa vs. 14 days with Bed Bug Killer). Sub-label rate exposure to CimeXa indicated that the pyrethroid-resistant strain possessed a degree of tolerance to this product, surviving 50% longer than the susceptible strain. This is the first study to suggest that mechanisms conferring resistance to pyrethroids, such as cuticular thickening, may have potential secondary impacts on non-synthetic insecticides, including desiccant dusts, which target the bed bug’s cuticle.

Highlights

The re-emergence of bed bugs, namely both the common species, Cimex lectularius L., and the tropical species, Cimex hemipterus (F.) (Hemiptera: Cimicidae), as a public health pest over the last 15 years has presented a unique challenge from both a clinical and management perspective [1,2], and has necessitated a multi-disciplinary approach in an attempt to develop best practice control options [3,4]
Male bed bugs exposed to both applications rates of CimeXa dust began to succumb after more than 6 h of continuous exposure, with survival decreasing along a broadly inverse-sigmoidal manner over the resulting 36–72 h
At the prescribed label rate of CimeXa, complete mortality was achieved after 36 h for both strains of bed bugs, with no statistically significant difference (p = 0.899)

Summary

Introduction

The re-emergence of bed bugs, namely both the common species, Cimex lectularius L., and the tropical species, Cimex hemipterus (F.) (Hemiptera: Cimicidae), as a public health pest over the last 15 years has presented a unique challenge from both a clinical and management perspective [1,2], and has necessitated a multi-disciplinary approach in an attempt to develop best practice control options [3,4]. In recent times, dusts have been proposed for, and used, around the interior of properties (such as around the perimeter of bedrooms and lounge rooms, on bed frames and sofas, or as a fabric-treated “dust band” on furniture legs) as a low-cost, long-term residual treatment option applicable in properties housing the financially or socially disadvantaged [27,29,30,31] Such a modified application of dusts for bed bug control has the potential to achieve high levels of population reduction (typically in the vicinity of 95%–98%), but rarely complete elimination [29,30,31]

Methods

Results

Discussion

Conclusion