.lambda.-Cyhalothrin
Cyclopropanecarboxylic acid, 3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethyl-, (R)-cyano(3-phenoxyphenyl)methyl ester, (1S,3S)-rel-
EPA Substance Registry Services (SRS) listed active ingredient for pesticide products.
Safety around dogs & cats
As a more potent Type II pyrethroid, lambda-cyhalothrin warrants extra care around animals. Cats are highly sensitive to all pyrethroids owing to their glucuronidation deficiency (ASPCA, Pet Poison Helpline, VCA), and dogs, while more tolerant, can show tremors or neuroexcitation at higher exposures with these cyano pyrethroids (Merck Veterinary Manual). Keep pets off freshly treated areas until dry, keep them from drinking runoff, and never apply to an animal.
Moderate confidence. Ratings from ASPCA Animal Poison Control, the Pet Poison Helpline, and published veterinary toxicology. This is general information, not veterinary advice. If your pet is exposed, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
The evidence
- A Review of Studies Evaluating Insecticide Barrier Treatments for Mosquito Control From 1944 to 20182019ReviewWell-supported evidence
This review gathered decades of studies, spanning 1944 to 2018, on insecticide barrier treatments, the residual sprays applied to vegetation and structures around a property to control mosquitoes. Rather than run a new experiment, the authors synthesized what the accumulated evidence says about how well these treatments work, how long they last, and how performance differs between active ingredients. For a buyer thinking about a yard-spray program, the most useful question it addresses is how many weeks of protection one treatment realistically buys.
- Efficacy of Two Pyrethroid Insecticides Applied as Barrier Treatments for Managing Mosquito Populations in Suburban Residential Properties2007Field TrialWell-supported evidence
Barrier sprays are the other main way people treat an area rather than their skin: a pest-control operator sprays a residual pyrethroid onto the shrubs, low vegetation, and shaded resting spots around a yard, so mosquitoes that rest there pick up a lethal dose. This suburban field study tested two of these pyrethroids, lambda-cyhalothrin and bifenthrin, on real residential properties and measured how much they cut human biting compared with untreated control yards. It is directly relevant to anyone weighing a professional yard-spray service.
Regulatory notes
Source: EPA SRS active ingredient list export. Minimum risk (25(b)) status is applied separately when applicable.