Triflumezopyrim (Corteva Pexalon)

Corteva Pexalon (Triflumezopyrim 10% SC; Pyraxalt active) is the first commercial mesoionic insecticide and the sole molecule in IRAC Group 4E. It is positioned specifically for rice planthopper management, including imidacloprid-resistant populations.

Composition / Active ingredient

Active ingredient: Triflumezopyrim (Pyraxalt)
Formulation: 10% SC (suspension concentrate)
Chemical class: Mesoionic pyrimidinium inner-salt — first of its kind commercially

Mode of action

Triflumezopyrim is a nicotinic acetylcholine receptor (nAChR) channel blocker, but at a distinct sub-class from neonicotinoids (Group 4A) or sulfoxaflor (4C) or flupyradifurone (4D). It is classified as IRAC Group 4E — a unique mesoionic mode. Where neonicotinoids open the receptor channel, triflumezopyrim locks the channel in the closed state, preventing nerve signalling and causing rapid feeding cessation. The different binding profile is what gives it activity on imidacloprid-resistant brown planthopper (BPH) populations.

Target use and dose

CIBRC-registered exclusively for rice planthoppers:

Brown planthopper (BPH), Nilaparvata lugens
White-backed planthopper (WBPH), Sogatella furcifera

Standard dose is 94 ml/acre at booting in 200 L water. Feeding cessation occurs within minutes; residual control extends up to 21 days. The product is rain-safe within hours of application.

Safety and regulatory status

Triflumezopyrim has a favourable safety profile for pollinators and is positioned as a key resistance-management tool in Indian rice IPM. For planthopper management, the typical rotation sequence within a season pairs Pexalon (Group 4E) with the pymetrozine + dinotefuran combo Pymetrozine Dinotefuran Combos (Group 9B + 4A) and feeding blockers like Flonicamid Ulala (Group 29) — three unrelated modes for hopper resistance management.

References

Pexalon. Corteva India.
Pyraxalt Tech Bulletin 2019. Corteva.