Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2012
Publication Date: 3/1/2013
Citation: Valles, S.M., Porter, S.D. 2013. Procedures to mititgate the impact of Solenopsis invicta Virus 3 in fire ant (Hymenoptera:Formicidae) rearing facilities. Florida Entomologist. 96:252-254. Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 350 million acres. It causes economic losses that exceed 6 billion dollars annually in the United States and poses a threat to human health. SINV-3 is an RNA virus discovered recently by ARS scientists that infects the red imported fire ant. This virus causes fire ant mortality to such a degree that it makes experimental studies very difficult. USDA-ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) have developed a rearing protocol permitting virus-free rearing of fire ants in the laboratory. This protocol is crucial to ongoing research on this invasive pest ant.
Technical Abstract: During the initial characterization of Solenopsis invicta virus 3 (SINV-3), virus-infected fire ant colonies were retrieved from the field and maintained in the laboratory rearing facility at the USDA, Gainesville, FL. During this time, all S. invicta colonies housed in the facility contracted SINV-3 infections. Initial attempts to maintain areas free of SINV-3 were unsuccessful— laboratory insectaries repeatedly cycled through growth (of newly acquired field colonies) followed by colony collapses caused by SINV-3 over the ensuing 3 years. The objectives of this research were to determine methods to render the virus inactive and evaluate the effectiveness of their use in limiting the impact of SINV-3 in fire ant rearing facilities. All decontamination treatments significantly reduced the amount of SINV-3 capable of being detected by RT-PCR. However, bleach and UV exposure were the most effective nearly completely eliminating detection of SINV-3 RNA after treatment. A UV-equipped air filter and specific cleaning and handling protocols were developed and evaluated for their ability to maintain rearing insectaries free of SINV-3 infections. The result was that we were able to maintain and conduct tests on dozens of fire ant colonies for nearly one year without any of the colonies becoming infected with SINV-3.