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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL AND PROTECTION TOOLS FOR INTEGRATED PEST MANAGEMENT OF MOSQUITOES AND FILTH FLIES Title: Current Status of the Mosquito Baculovirus Cuninpv for Control of Culex Vectors of Encephalitis

Author
item Becnel, James

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 19, 2005
Publication Date: May 19, 2005
Citation: Becnel, J.J. 2005. Current status of the mosquito baculovirus cuninpv for control of culex vectors of encephalitis. Meeting Abstract.

Technical Abstract: Baculoviruses have been intensively investigated due to their potential as biological control agents for insects and because of their importance as gene expression vectors. Mosquito baculoviruses have been difficult if not impossible to transmit and therefore basic biological studies have been hindered. A baculovirus has been discovered that caused repeated and extended epizootics in field populations of Culex nigripalpus and Culex quinquefasciatus in Florida, USA. Attempts to transmit this baculovirus to larvae in the laboratory were unsuccessful. A salt mixture similar to that found in water supporting infection in the field was used in laboratory bioassays and indicated that certain salts were crucial to transmission. Investigations revealed that transmission is mediated by divalent cations: magnesium is essential, whereas the presence of calcium inhibits the activity of magnesium to mediate transmission. These investigations demonstrating the role of magnesium and calcium in facilitating infectivity of the CuniNPV baculovirus have direct and important implications for utilizing baculoviruses for mosquito control. This new insight on transmission may facilitate the discovery and development of additional baculoviruses for the control of other important mosquito vectors. Two different approaches are being pursued for utilizing mosquito baculoviruses for mosquito control. The first is the classical approach to develop CuniNPV as a new type of biopesticide for mosquitoes. This requires the microencapsulation of the virus and magnesium into a formulated product that could be applied as a conventional larvicide. The encapsulated particle would be between 5-50 microns in size, remain stable in the aquatic environment until ingested by mosquito larvae. The encapsulation material is designed to dissolve in response to the alkaline conditions of the larval midgut to selective deliver the virus and magnesium to the target sites. The second approach is technology based on biological mining and functional genomics of mosquito baculoviruses. CuniNPV has a circular, double-stranded DNA genome of 108,252 base pairs and 109 predicted genes. Information on the viral genome together with new mosquito genome data will be utilized to conduct functional genomic studies of CuniNPV to identify genes that direct transmission, host range and virulence in Culex spp. and to study CuniNPV-Culex interactions. Biological mining of the CuniNPV genome and comparative genomics offers exciting possibilities for the development of novel mosquito control strategies and tools.

Last Modified: 10/24/2014
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