Efficacy and utility of isocycloseram a novel isoxazoline insecticide against urban pests and public health disease vectors

Abstract

BACKGROUND: Isoxazolines inhibit γ-aminobutyric acid chloride channels in insects and acarids by binding to postsynaptic receptors. This prevents chloride influx, leading to depolarization/hyperexcitation, paralysis, and death. Here, we evaluated the potential utility of a novel isoxazoline, isocycloseram, against several urban insect pests. RESULTS: Isocycloseram was active at low doses against the German cockroach, Blattella germanica (L.) [median lethal dose (LD50) 5–15 ng per insect at 72 h, topical assays]; Argentine ant (Linepithema humile Mayr), Pharaoh ant (Monomorium pharaonis (L.), common bed bug (Cimex lectularius (L.) (approximately 40 mg m−2, residual surface spray); Eastern subterranean termite (Reticulitermes flavipes (Kollar) and Formosan subterranean termite (Coptotermes formosanus Shiraki) (5 μg g−1 w/w, tunneling assays); and mosquito, Anopheles stephensi Liston (120 and 150 mg m−2 treated surfaces, aged indoors for 9 months). Additionally, cockroach gel bait at 1% isocycloseram (w/w) caused 95–100% mortality in German, American (Periplaneta americana (L.), and oriental (Blatta orientalis (L.) cockroaches within 5–14 days. CONCLUSIONS: Isocycloseram proved to be active against both laboratory and field populations of German cockroaches at doses lower or equal to those of other chemicals. Ants, bed bugs, and mosquitoes readily acquired lethal doses of isocycloseram from different surfaces treated with formulated products. Given its non-repellent nature, delayed effects, and activity at low rates, isocycloseram can be a very effective compound against subsocial, social, and other human disease vector insect pests. © 2024 Society of Chemical Industry.