The Red Imported Fire Ant in California Dr. Les Greenberg University of California, Riverside
Origin of Imported Fire Ants • South America: Brazil, Uruguay, Paraguay, Argentina
U.S. Introduction • Introduction to Mobile, Alabama, between 1930-1940 • Probably arrived in ship ballast • From there, spread outward to the Southeast and West
Potential spread of fire ants • Originally 10° F. isothermal line; now at 0° F. • Limiting factor of moisture • Adaptation to man-made environment
Locating Infestations • Visual inspection • Luncheon meat • Corn chips
Biological Control Agents • Phorid flies: decapitating flies • Protozoan parasites: Thelohania • Other species of ants
Phorid Fly Releases • Between 1996 and 2002 the decapitating fly, Pseudacteon tricuspis, was released at 56 sites in the southeastern United States • Most releases have been made by the USDA-ARS, CMAVE, Gainesville, FL ( 32 sites) and the University of Texas, Austin (15 sites).
Phorid Fly Releases • Overwintering populations of flies were successfully established at 19 sites in 6 states (AL-3, FL- 5, LA-3, MS-1, SC-2, TX-5).
Thelohania solenopsae, a microsporidian intracellular parasite • The most common fire ant pathogen in Brazil • It was discovered in the US in 1998 (FL, TX, MS, OK). • Decreases ant’s longevity and reduces colony size
Treatments 2007 • Treatments used • 3 gals fipronil spray perimeter • 1 gal fipronil spot • 3 gals bifenthrin spray • Combination of fipronil spray and bifenthrin granules • Bait stations with imidacloprid
Data From a Typical House • Lawn area measured • Water meter recorded • Runoff estimated • Sprinkler locations mapped • Collection site noted • Time that irrigation is on
Dam placement at curb • 4-in styrofoam cut into U-shape • Sand bags on styrofoam • Styrofoam and sand bags put inside disposable plastic bags
Volumetric flow rate (Q), the volume of fluid which passes through a given volume per unit time • Q = A x v, where • A = area (depth and width of water stream) • v = uniform average velocity of water (how long it takes to flow a known distance) • Q*time - gives us an estimate of total water runoff
Sample processing • One liter sample collected from one bank of sprinklers per house • Sample stored at 40C • Sample analyzed at laboratory of Dr. Jay Gan in environmental sciences, UC Riverside
Schedule 2007 • Pretreatment ant evaluations and water samples collected in June • Post-treatment ant evaluations done at 1,2,4,and 8 weeks • Post-treatment water samples collected at 1, 4, and 8 weeks