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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Imported Fire Ant and Household Insects Research » Research » Publications at this Location » Publication #430416
Research Project: Detection and Management of Invasive Ants

Location: Imported Fire Ant and Household Insects Research

Title: Evaluation of organosilicone surfactants as synergists of Solenopsis invicta virus 3 in Solenopsis invicta

Author
item White, Roxie
item Valles, Steven
item Read, Quentin

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2026
Publication Date: 2/23/2026
Citation: White, R.L., Valles, S.M., Read, Q.D. 2026. Evaluation of organosilicone surfactants as synergists of Solenopsis invicta virus 3 in Solenopsis invicta. Journal of Invertebrate Pathology. 216:108573. https://doi.org/10.1016/j.jip.2026.108573.
DOI: https://doi.org/10.1016/j.jip.2026.108573

Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 300 million acres. It causes approximately $8 billion in damage annually and poses a serious threat to human health from allergic reactions. Biological agents are thought to provide the most sustainable, cost-effective and wide-reaching control of this ant in the USA. An important group of biological control agents against the red imported fire ant is viruses, including Invictavirus solenopsae. Studies were conducted by scientists in the Imported Fire Ant and Household Insects Research Unit (ARS), Gainesville, Florida, to improve the efficacy of Invictavirus solenopsae by added an organosilicone adjuvant to the bait formulation. Results show that organosilicone adjuvants provide marginal improvement in the pathogenicity of Invictavirus solenopsae. However, the results do indicate that Invictavirus solenopsae may be made more efficacious with certain adjuvants.

Technical Abstract: Solenopsis invicta virus 3 is an effective biological control agent against the red imported fire ant, S. invicta. We attempted to improve the virus’ effectiveness with organosilicone adjuvants (hydroxy trisiloxane [hydroxyTSX] and methoxy trisiloxane [methoxyTSX]). S. invicta colonies were exposed to one of four treatments: (1) control, (2) trisiloxane [hydroxy or methoxy], (3) SINV-3, and (4) SINV-3 + trisiloxane [hydroxy or methoxy]. Brood production increased in the control (7.4-fold) and hydroxyTSX (5.1-fold) groups over the course of the study, while the brood rating among the SINV-3 and SINV-3 + hydroxyTSX groups remained essentially unchanged at 1.5-fold and 1.6-fold, respectively. The groups without SINV-3 treatment showed significantly greater brood production compared with those exposed to SINV-3. However, there was no significant difference between the SINV-3 and SINV-3 + hydroxyTSX treatments. Similarly, among the methoxyTSX group of colonies, brood production increased in the control (2.7-fold) and methoxyTSX (2.3-fold) groups. Brood production decreased in the SINV-3 (3.3-fold) and SINV-3 + methoxyTSX (5.9-fold) groups by day 34. There was no significant difference between these two treatments on day 34. The combination of methoxy or hydroxy trisiloxane and SINV-3 did not have an impact on queen weight or fecundity beyond SINV-3 treatment alone. The potential for using methoxy or hydroxy trisiloxane as a synergist for SINV-3 efficacy is minimal when used as in this study.