Fungal infection counters insecticide resistance in African malaria mosquitoes

Abstract

The evolution of insecticide resistance in mosquitoes is threatening the effectiveness and sustainability of malaria control programs in various parts of the world. Through their unique mode of action, entomopathogenic fungi provide promising alternatives to chemical control. However, potential interactions between fungal infection and insecticide resistance, such as cross-resistance, have not been investigated. We show that insecticide-resistant Anopheles mosquitoes remain susceptible to infection with the fungus Beauveria bassiana. Four different mosquito strains with high resistance levels against pyrethroids, organochlorines, or carbamates were equally susceptible to B. bassiana infection as their baseline counterparts, showing significantly reduced mosquito survival. Moreover, fungal infection reduced the expression of resistance to the key public health insecticides permethrin and dichlorodiphenyltrichloroethane. Mosquitoes preinfected with B. bassiana or Metarhizium anisopliae showed a significant increase in mortality after insecticide exposure compared with uninfected control mosquitoes. Our results show a high potential utility of fungal biopesticides for complementing existing vector control measures and provide products for use in resistance management strategies.biopesticide ͉ DDT ͉ pyrethoids ͉ resistance management ͉ vector control

Electrostatic coating enhances bioavailability of insecticides and breaks pyrethroid resistance in mosquitoes

“…Electrostatic netting thus can provide a means to apply and deploy novel insecticides currently under development (16), which can further assist in the management of insecticide resistance. Further experiments will focus on using combination products, such as multiple classes of insecticides and combinations with potentially synergistic biological agents (37,38), and on determining particle characteristics to investigate binding and retention on the electrostatic netting. In-depth knowledge of the binding strength of various types of insecticidal particles to the coating might result in further optimization of electrostatic netting for insect control.…”

CYP52X1, Representing New Cytochrome P450 Subfamily, Displays Fatty Acid Hydroxylase Activity and Contributes to Virulence and Growth on Insect Cuticular Substrates in Entomopathogenic Fungus Beauveria bassiana

“…Two different assay conditions were tested for each cell type (1). In a topical application, the larvae were dipped for 5-10 s in solutions of 1 ϫ 10 8 conidia/ml harvested in sterile distilled H 2 O, and the excess liquid on the insect bodies was removed by placement on dry paper towel.…”

“…As a broad host range pathogen, strains of B. bassiana have been exploited for use against agricultural pests and for insects that act as human and animal disease vectors (1)(2)(3)(4). Infection of insects begins with attachment of fungal spores to the cuticles of target hosts, and in response to surface cues the fungus germinates; the emerging germ tubes produce a variety of enzymes that combined with mechanical pressure begins the process of cuticle penetration (5)(6)(7)(8)(9).…”

Screening of bacterial strains for developing effective pesticide-tolerant plant growth-promoting microbial consortia from rhizosphere soils of vegetable fields of eastern Uttar Pradesh, India

“…Therefore, insecticides as pesticide application in vegetable fields caused to decrease the population of bacteria and actinomycetes as compared to fungi. Fungi are more resistance to insecticide (Farenhorst et al 2009;Ambethgar 2009). At the time of colony counting on media plates, different and similar type colonies were found.…”