2007 Annual Report
1a.Objectives (from AD-416)
The imported fire ants are serious pests affecting humans, wildlife, crops, and livestock, as well as a health hazard to humans. The goal of this project will be the development of management tools for a sustainable reduction of imported fire ant populations. To achieve this goal a proactive area-wide program will be implemented to suppress imported fire ant populations and to end the spread of infestations. A regional management program developed with Mississippi State University will include product testing, natural history, ecology, and biological control.
1b.Approach (from AD-416)
Cultural, biological, and chemical control methods need to be integrated into proactive, regional fire ant management programs. New bait technologies utilizing synthetic chemicals and microbials will be evaluated to identify the most effective treatments for implementation into large scale programs. Native species of ants will be inventoried to compare diversity of native ant species with abundance of imported fire ants either naturally or under different management strategies. Area-wide programs will be implemented through cooperation with the Mississippi Agricultural and Forestry Experiment Station. Information will be coordinated with the ARS Information Office and the Mississippi State University Extension Service.
This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Mississippi State University. Additional details of research can be found in the report for the in-house project 6402-22320-003-00D, "Regional Integrated Management of Imported Fire Ants." A minimum of 3 bacteria and 5 fungi have repeatedly been shown to kill red imported fire ant (RIFA) colonies within 4 days of treatment. Further evaluation in field-caged environment for those that showed as promising candidates during laboratory evaluation is currently being evaluated to correlate the in-situ results of the putative biological control candidates or antagonism activities.
Various SEM (Scanning Electron Microscopy) and LM (Light Microscopy) techniques were used to investigate the morphology, number, and distribution of cuticular sensilla on the mouthparts (labial palpus, maxillary palpus and galea) of the RIFA larva. The maxillary palpus had four sensilla of three distinct types (T1,T2,T3) and tha galea and labial palpus each had two sensilla, the T1. All of these sensilla stained intensely with silver nitrate which indicated their porosity. The methylene blue staining showed that the sensilla had multiple neurons. These two characteristics showed that the sensilla were chemo-receptors and are probably associated with various larval behaviors by mediating chemical cues.
Research to evaluate fire ant management to reduce fire ant mound-related costs associated with the harvesting of soybeans, has been initiated. Applications of bait to large plots, generally several acres up to about 16 acres comprising areas up to one half of each field treated have been made to fields with numerous mounds during the spring of 2007. Preliminary results determined from counts of active mounds approximately one month after application indicate that the number of active mounds were reduced drastically in treated areas compared to untreated areas of the fields.
A comprehensive and curated collection of Formicidae representing ant species found in the southeastern United States, especially AL and MS, has been developed in the Mississippi Entomological Museum to aid identifications and hold voucher specimens for ant research. Nomenclature of species in the Mississippi Entomological Museum (MEM) has been updated with current catalogs. Identifications have been provided for numerous individuals from a wide range of universities and state and federal agencies. A web site dedicated to the ants of the southeastern United States has been developed and features species lists, identification keys, photographs, collecting logs, collecting tips, and a glossary of terms. Species pages have been developed with photos of the majority of the southeastern species. Diagnoses, biological information, and distributions will be gradually added. Ongoing monitoring of this project is accomplished through emails and phone conversations.