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

Fire ant quarantine

Potential spread of fire ants Originally 10° F. isothermal line; now at 0° F. Limiting factor of moisture Adaptation to man-made environment

U. S. Expansion

Mating

Fire Ant Dispersal

Stinging and Pustule Formation

Transformers Shorted

Infested Areas of Southern California

Locating Infestations Visual inspection Luncheon meat Corn chips

Nurseries in Trabuco Canyon

Subterranean Trail Under Plastic

Flower beds in Los Alamitos

Coachella Valley Golf Courses

Mounds on Mowed Grass

Mound at Sprinkler

Exit holes from underground foraging trails on putting green

Cleveland National Forest

2500 ft

Wetlands Rancho Santa Margarita

Infested Areas of the Central Valley

Almond Groves in Central Valley

Biological Control Agents Phorid flies: decapitating flies Protozoan parasites: Thelohania Other species of ants

Phorid Flies

Phorid Flies (Decapitating Flies)

Phorid Flies

Phorid Fly Release

Phorid Fly Releases

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).

Phorid Fly Expansion in Florida

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

Inoculating Mound with Thelohania

Insecticide Runoff from Treated Houses

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

Water collection dam

Dam placement at curb 4-in styrofoam cut into U-shape Sand bags on styrofoam Styrofoam and sand bags put inside disposable plastic bags

Sample collection

60-ml aquatic pipette

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

Concentration of fipronil and its byproducts in runoff desulfinyl sulfide sulfone

Concentrations of fipronil and bifenthrin in runoff With Ceriodaphnia LD50s Fipronil LD50 Bifenthrin LD50

2008 6 different pesticide treatments 3 houses sampled per treatment for insecticide runoff = 18 houses sampled Sample periods Pretreatment 1 day 1 week 2 week driveway flush

This summer’s fipronil treatments All fipronil treatments limited to 1 gal 1 gal peripheral spray -- pin stream nozzle Spot treatments Same as above but not within 15 ft of street and 5 ft of sidewalks

This summer’s bifenthrin treatments All use 3 gals Pin stream nozzle perimeter treatment Traditional fan nozzle perimeter application Spot treatments with 3 gals, but not within 15 ft of street or 5 ft of sidewalks

Conclusions We can successfully monitor how much insecticide runs off from treated houses due to irrigation We can test different application techniques to minimize insecticide runoff