Attract-and-Kill Bait Formulations Integrating Wild Botanical Extracts and Fecal Aggregation Pheromones Against Periplaneta americana

Abstract

This study evaluated the bio-insecticidal efficacy of thermal and cold aqueous extracts derived from two indigenous desert plants of Al-Muthanna Governorate, Iraq—Chenopodium album L. and Achillea fragrantissima (Forssk.) Sch.Bip.—against the American cockroach (Periplaneta americana). We further investigated the synergistic effect of supplementing fecal aggregation pheromones into botanical bait formulations targeting sixth-instar nymphs and mature adults. Phytochemical screening confirmed the presence of key secondary metabolites, including polyphenols, tannins, alkaloids, saponins, flavonoids, coumarins, glycosides, and terpenes. Laboratory bioassays showed concentration- and time-dependent toxicity, with thermal extracts displaying higher potency than cold extracts, and nymphs showing greater susceptibility than adults. Incorporating the aggregation pheromone markedly improved bait performance, achieving 100% nymphal mortality within 6 days for both plant species. Adult mortality reached 100% between days 6–9 for A. fragrantissima combinations and days 9–15 for C. album. In contrast, unsupplemented 10% plant preparations resulted in peak 15-day mortality rates of only 66.1%–79.2% in nymphs and 53.6%–64.1% in adults. These results show that fecal aggregation pheromones serve as key behavioral stimulants that enhance bait ingestion, thereby maximizing the lethal action of toxic plant compounds (particularly midgut-disrupting saponins, neurotoxic alkaloids, and tannins). Thus, pheromone-fortified botanical baits present an effective, eco-friendly attract-and-kill strategy for integrated management of P. americana.