Laboratory and field evaluations of biodegradable boric acid hydrogel baits for the control of Argentine ant (Hymenoptera: Formicidae) in urban citrus orchards

Wednesday, November 16, 2022

9:48 AM – 10:00 AM PT

Location: Vancouver Convention Centre, Meeting Room 214

Presenting Author(s)

Dong-Hwan Choe

Associated CE Specialist / Associate Professor
University of California
Riverside, California

Co-Author(s)

BL

Benning Le

University of California
Riverside, California
KC

Kathleen Campbell

University of California
Riverside, California
HP

Ho Eun Park

University of California
Riverside, California
Shu-Ping Tseng

Post doc
University of California
Riverside, California
RP

Raju Pandey

Citrus Research Board
Riverside, California
GS

Gregory S. Simmons

USDA-ARS
Salinas, California
Ruth E. Henderson

USDA-ARS
Salinas, California
Michael K. Rust

Retired Professor of Entomology
University of California
Riverside, California
Chow-Yang Lee, BCE

Professor & Endowed Presidential Chair in Urban Entomology
University of California
Riverside, California

Argentine ant is a major pest in agricultural environments in California. Besides insecticide sprays, liquid baiting has been considered as an effective method to suppress the Argentine ant populations with minimal non-target impact. To improve the economic feasibility of liquid baiting, hydrogel materials have been investigated as a carrier for liquid ant baits in urban or agricultural environments. Here, a biodegradable calcium alginate hydrogel containing boric acid as an active ingredient was tested for its effectiveness in suppressing Argentine ant populations in citrus orchards. Laboratory tests with small colonies of Argentine ant indicated that hydrogel bait with boric acid (1%) was effective in killing Argentine ant workers, and a preservative, potassium sorbate (0.25%) did not impact the efficacy of boric acid bait. Large quantities of hydrogel bait were produced by a newly-developed continuous production method, and subsequently applied in citrus orchards. Four separate monthly bait applications (June-September) provided up to an 80% reduction in the Argentine ant activity when compared to untreated control zone. Post-treatment survey findings on plant pests (e.g., Asian Citrus Psyllid) in the citrus orchards will be also discussed.