Development of efficacious RNAi-based baits for RIFA control

Imported Fire Ants (Solenopsis richteri Solenopsis invicta) are invasive pests which currentlyinfest over 140 million ha in 14 states. Damages related to fire ants have a significant impact onmany economic sectors including agriculture and biodiversity. The estimated annual cost spent onfire ant control is 3 billion dollars. Current chemical insecticides used in fire ant control are notselective causing unnecessary ecological damage. RNAi represents a viable option for the selectiveand safe control of fire ants. However current RNAi triggers are polar have poor permeabilityacross biomembranes and associate poorly with the oil in broadcast bait formulations. The overallgoal of this project is to develop chemically modified RNAi triggers with enhanced deliveryproperties and oil solubility to yield bait formulations that show improved efficacy against RIFA incolonies. To attain this goal we will demonstrate that we can accomplish the following technicalobjectives: 1) Identify optimal combination of phenol ether moiety extent of the modification andconcentration to yield high potency modified RNAi triggers (MdsRIFAs) 2) Identify oil solubleMdsRIFA candidates prepare bait formulations and test their stability and 3) Test the ability ofthe MdsRIFA bait formulation to induce RIFA lethality on a colony scale. The project will build onresults from a prior NSF SBIR Phase I project and it will be conducted in collaboration with theImported Fire and Household Insects Research Unit of the Agricultural Research Service inGainesville Florida through a CRADA with the USDA.