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United States Department of Agriculture

Agricultural Research Service

Title: Microsporida in Mosquitoes: Control Versus Management Strategies

Author
item Becnel, James

Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 3, 2004
Publication Date: August 3, 2004
Citation: Becnel, J.J. 2004. Microsporida in mosquitoes: control versus management strategies. Society for Invertebrate Pathology Annual Meeting.

Technical Abstract: The attraction of microsporidia for management of mosquitoes lies with their ability to cause larval epizootics, continuously cycle within a host population, and spread to new habitats. The idea of utilizing these 'natural enemies' of mosquitoes as manipulative control agents was perhaps first raised by Kudo (1921) who suggested that larval sites might be contaminated with microsporidian infected mosquito tissues. He further suggested (unaware at that time of the mechanism of transovarial transmission) that infected adults could distribute the parasite to new sites that 'may escape our watchful eye' by dying during oviposition,. The complex life cycles exhibited by microsporidian parasites of mosquitoes and the chronic nature of the infection precludes their use as biorational insecticides. The approach to utilizing microsporidia as part of a program to manage mosquitoes must rely on a thorough knowledge of the dynamics of the host-parasite relationship. It is crucial to look beyond short-term population reduction and instead, rely on the benefits of long-term abatement as part of an overall management strategy. The recognition and protection of seasonal epizootics would prevent disruption of the natural balance and control, thus maintaining the disease in the population. Additional relief could be expected due to a reduction in the survival, vigor and reproductive success of infected mosquitoes during other parts of the life cycle. Much of the information concerning the life cycles and evaluations of polymorphic microsporidia has been derived from studies on Amblyospora dyxenoides, Amblyospora connecticus and Edhazardia aedis. Incorporation of E. aedis as a classical biological control agents for Aedes aegypti will be discussed and the circumstances where this approach might be feasible. In contrast, understanding the dynamics of A. connecticus in the mosquito and intermediate host will be presented with respect to mosquito control practices that take into account how conventional control practices can be incorporated so as not to interfere with natural control by the pathogen. Utilizing microsporidia for the management of mosquitoes is proposed not as a sole method but rather as part of the natural complex of regulatory factors. This approach recognizes that eradication of the target mosquito is an unrealistic expectation but with a combination of physical, cultural, chemical and biological control methods, mosquito vectors and pests can be regulated.

Last Modified: 12/21/2014
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