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United States Department of Agriculture

Agricultural Research Service

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Research Project: Diversity of Entomopathogenic Fungi Affecting Diptera Important for Human and Animal Health in Areas of Goias and Tocantins

Location: Biological Integrated Pest Management Unit

Project Number: 1907-22410-005-08
Project Type: Nonfunded Cooperative Agreement

Start Date: Mar 31, 2014
End Date: Apr 14, 2017

Objective:
Discover the biodiversity in the Brazilian states of Goiás and Tocantins of fungal entomopathogens (EPF) affecting dipteran vectors (mainly mosquitoes, blackflies, sandflies, and biting midges) of human and animal diseases, as well as muscoid flies that are major nuisances and disease vectors in poultry houses. While the Brazilian mycobiota of EPF remains understudied, most research and practical applications of EPF throughout the world focuses on agriculturally important insects; the focus of this proposal on pathogens affecting dipteran vectors of such major diseases as malaria, dengue, yellow fever, river blindness, leishmaniasis, and bluetongue of cattle is unprecedented. Little practical effort has been devoted to control these dipteran vectors by any means except with chemical pesticides. The proposed study includes intensive field efforts to recover a wide range of fungal (and oomycete) pathogens of these dipteran vectors and of muscoid flies in poultry houses; to isolate, to culture, and to preserve these fungi for the long term in collections at the host institution (IPTSP), at the main Brazilian collection for fungal entomopathogens (Embrapa, Brasília) and in the ARSEF culture collection (Ithaca, NY); to identify these fungi usnig the best possible technologies and most current (albeit changing) systematics of fungi; to begin laboratory bioassay studies to evaluate these fungi as pathogens against both Aedes aegypti (a major vector of many important diseases in central Brazil) and Musca domestica (the major dipteran nuisance/vector in poultry houses); and to study some fundamental issues of the organismal and developmental biology of some of these fungi to increase the overall understanding of how they interact with their hosts. This project would significantly expand the knowledge of the diversity and distribution of EPF affecting dipteran vectors and pests in Brazil; would significantly increase the holdings of ARSEF and key Brazilian culture collections of these fungi; would result in the descriptions of new species and improved taxonomies for these fungi; would significantly enrich the training of graduate students in one of Brazil’s largest insect pathology groups; and would strengthen and expand research contacts between key Brazilian and American laboratories dealing with entomopathogenic fungi.

Approach:
Standard collecting techniques will be used at urban sites in or near Goiania, especially for diseased or living and possibly diseased mosquitoes (to be incubated for several days after collection to allow any pathogens to develop and sporulate) and also for muscoid flies in poultry houses. All fungi detected from collected insects will isolated and identified as possible pathogens; bioassay studies will verify activities against hosts for pathogenic fungi (but not for putative saprobes). Collections in minimally disturbed habitats will be made in parks in western and northern Goiás, and also in comparatively undisturbed and park-like areas (some of which are reserves for indigenous populations) in Tocantins state. Standard morphological and (gene sequence-based) molecular approaches will be used to identify all isolates of EPF. Cultures of Beauveria and Metarhizium species obtained during these collections will also be submitted to Embrapa’s collection of EPF in Brasilia to help validate and improve the newly begun use of MALDI-TOF mass spectroscopy for identifications of species in these important genera. All EPF cultures will be preserved cryogenically using standard techniques at -80 degC and in liquid nitrogen dewars at -196 degC. Standard rearing techniques for mosquitoes and houseflies will provide insects for bioassays of the virulence and pathogenicity of isolates obtained from field collections. Unresolved but important questions about the organismal biology and interactions between fungi and their hosts will be studied using microscopic, physiological and other approaches in laboratories of the Brazilian and ARS investigators; these studies will facilitate the eventual production, formulation, and utilization of these fungi as practical biological control agents.

Last Modified: 9/10/2014
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