Laboratory and Field Trials of Commercial Imidacloprid and Fipronil Gel Baits against Periplaneta americana Linnaeus [Blattodea: Blattidae] and Blattella germanica Linnaeus [Blattodea: Ectobiidae]
NJE Vol. 42(1) : 85-95, 2026
DOI.10.36108/NJE/6202/24.0170
ADETORO, F.A*., OLADAPO, K.P., ABU, S., ADENIRAN, J., KEMABONTA, K.A
Applied Entomology Unit, Department of Zoology, Faculty of Life Sciences, University of Lagos, P.M.B. 101017, Lagos, Nigeria.
Abstract
This study evaluated the efficacy of Imidacloprid (2.1%) and Fipronil (0.05%) gel baits against Periplaneta americana and Blattella germanica through laboratory and field trials. In the field, pre-treatment monitoring over seven days revealed moderate to high cockroach activity, particularly among B. germanica. Following the application of 0.5 g of each gel bait, complete elimination of both species was observed within seven days, indicating 100% reduction in population. Laboratory trials involved graded bait concentrations applied in duplicate tanks, with ten individuals per dose. Imidacloprid induced rapid knockdown in P. americana within 55 minutes, while B. germanica exhibited delayed knockdown at approximately 7 hours and 20 minutes. Fipronil showed strong bait attraction in P. americana, with abdominal shivering observed around 6 hours post-ingestion. B. germanica responded more acutely to Fipronil, with faster mortality and no withdrawal behavior. LD50 values ranged (0.055 – 0.854) g across species and concentrations, with dose-dependent increases in toxicity factors. No mortality occurred in control groups. These findings confirm the high efficacy of both gel bait formulations, with Imidacloprid being most effective bait for P. Americana cockroach management
Keyword: American cockroach, German cockroach, Gel baits, Knockdown time, Urban ecology