Common name:    Lambda-cyhalothrin

Other name: lambda-cyhalothrin (BSI, draft E-ISO); lambda-cyhalothrine ((f) draft F-ISO)

Iupac name: A reaction product comprising equal quantities of (S)-α-cyano-3- Phenoxybenzyl(Z)-(1R,3R)-3-(2-choro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclopro= Anecarboxylate and (R)- α-cyano-3-phenoxybenzyl

Type: Insecticide for Agriculture

CAS RN: [97465-08-6]

M.F.:                                   C₂₃H₁₉ClF₃NO₃

Mol Wt:                               449.9

 

Form (appearance): Colourless solid; (tech. is a dark brown/green solidified melt)

Composition:: Tech. grade is c. 81% pure.
M.P.: 49.2℃; (tech., 47.5-48.5℃)

B.P.: Does not boil at atmospheric pressure

V.P.: 2 × 10^-4 mPa (20℃, est.); 2 × 10^-1 mPa (60℃, interpolated)

F.P.: 185 ℃ (tech., Pensky-Martens closed cup)

S.G.:1.33 g/mi (25℃)

Solubility.: In water 0.005 mg/l (20℃). In acetone, methanol, toluene, hexane, ethyl acetate >500 g/l.

Stability: Stable to light. Stable on storage for more than 6 months at 15-25 ℃.

Henry: 2 × 10^-2 Pa m³ mol^-1

K_owlogP: 7 (20℃)

Pka: >9 (hydrolysis prevents measurement)

 

Formulation types: CS; EC; ED; EW; UL; WG; WP

Mode of action: Non-systemic insecticide with contact and stomach action, and repellent properties. Gives rapid knockdown and long residual activity

Uses: Control of a wide spectrum of insect pests, e.g. aphids, Colorado beetles, thrips, Lepidoptera larvae, Coleoptera larvae and adults, etc., in cereals, hops, ornamentals, potatoes, vegetables, cotton, and other crops. Provides good control of insect-borne plant viruses. Also used for control of insect pests in public health.

 

Oral: Acute oral LD₅₀ for male rats 79, female rats 56, mice 20 mg/kg.

Skin and eye: Acute percutaneous LD₅₀ for rats 632-696 mg/kg. Mild eye irritant; non-irritant to skin (rabbits). Not a skin sensitiser (guinea pigs).

Inhalation: LC₅₀ (4 h) 0.06 mg/l air (total particulate).

Noel: (1 y) for dogs 0.5 mg/kg daily.

ADI: 0.005 mg/kg.
Other Non-mutagenic in the Ames test.

Toxicity: WHO (a.i.) II; EPA (formulation) II (`Karate`, `Warrior`)

EC hazard: T+; R26| T; R25| Xn; R21| N; R50, R53

 

Birds: Acute oral LD₅₀ for mallard ducks >3950 mg/kg. Dietary LC₅₀ for quail >5300 mg/kg. No accumulation of residues in eggs or tissues.

Fish: LC₅₀ (96 h) for bluegill sunfish 0.21, rainbow trout 0.36 μg/l.

Daphnia: EC₅₀ (48 h) 0.36 μg/l.

Algae: E_rC₅₀ (96 h) for Selenastrum capricornutum >1000 μg/l.
Other aquatic spp. Intrinsic toxicity to aquatic organisms is greatly reduced by rapid loss from the water by adsorption and degradation.

Worms: LC₅₀ for Eisenia foetida >1000 mg/kg soil.
Bees: LD₅₀ (oral) 38 ng/bee; (contact) 909 ng/bee.
Other beneficial spp. Toxic to some non-target arthropods. Effects under field conditions reduced, with rapid recovery.

 

Plant: For details of metabolism of lambda-cyhalothrin in cotton and soya bean leaves, see D. A. French & J. P. Leahey, Proc. Br Crop Prot. Conf. - Pests Dis., 1990, 3, 1029-1034.

Animals: In rats, following oral administration, rapidly eliminated in urine and faeces. The ester group is hydrolysed, both moieties forming polar conjugates.

Soil/Environment: Rapidly degraded in soil; DT₅₀ for microbial degradation 23-82 d, for field soil 6-40 d. Strongly adsorbed to soil and sediment organic matter, K_oc 330000. Negligible potential for leaching of lambda cyhalothrin and its degradation products through soil. Rapid dissipation from water in aquatic systems. DT₅₀ for dissipation from surface waters in lab. water-sediment systems 5-11 h; in a microcosm DT₅₀ <3 h. Rapid and extensive degradation of parent compound in aquatic systems; DT₅₀ for degradation in lab. water-sediment systems 7-15 d; in a microcosm DT₅₀<3 h, DT₉₀ <3 d.