Thiamethoxam (Syngenta Actara)

Thiamethoxam is a second-generation neonicotinoid insecticide developed by Novartis (now Syngenta) and marketed in India as Actara 25% WG. It is one of the most widely used neonicotinoids in cotton, paddy and vegetable sucking-pest management.

Composition / Active ingredient

Active ingredient: Thiamethoxam
Formulation: 25% WG (water-dispersible granule)
Chemical class: Neonicotinoid (second generation, thianicotinyl)

Mode of action

Thiamethoxam is a nicotinic acetylcholine receptor (nAChR) competitive modulator, classified under IRAC Group 4A. Within the insect it is metabolised to clothianidin, the same active produced from clothianidin-based products; this metabolite is the dominant active form. Action is by ingestion and contact, with strong systemic and translaminar movement through xylem and phloem.

Target use and dose

CIBRC-registered crops include paddy, wheat, cotton, mango, citrus, vegetables, tea and mustard. Target pests:

Sap-suckers: aphids, whitefly, jassids, thrips, leafhoppers
Rice: stem borer, brown planthopper, gall midge
Tree crops: scales, mealybugs

Foliar dose is typically 40-80 g/acre depending on crop and pest; seed-treatment formulations (FS) are also used at 3-5 g/kg seed in cotton, paddy and vegetables.

Safety and regulatory status

Neonicotinoids including thiamethoxam are under regulatory restriction in the EU due to pollinator concerns; India retains its CIBRC registration but bee-safety label warnings apply around bloom. Whitefly resistance to neonicotinoids is widespread; rotation with Flonicamid Ulala (Group 29), Flupyradifurone Gracia (Group 4D — a structurally different nAChR modulator), Spirotetramat Movento (Group 23) and Diafenthiuron Pegasus (Group 12A) is essential.

References

Actara Insecticide. Syngenta India / BigHaat.
Actara — product label. Syngenta.