Mesosulfuron-methyl: A Selective Systemic Herbicide for Grass Weed Control

Technical Introduction

Mesosulfuron-methyl (IUPAC: methyl 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate) is a selective, systemic herbicide belonging to the sulfonylurea chemical class.

It is highly effective against grassy weeds, acting by inhibiting acetolactate synthase (ALS), an enzyme essential for the biosynthesis of branched-chain amino acids. This inhibition stops cell division and growth, eventually killing the weeds.

• Mode of Action: ALS inhibitor (HRAC Group B).

• Systemicity: Systemic; absorbed by leaves and roots, translocated throughout the plant.

• Spectrum: Primarily effective against annual and perennial grasses; minimal impact on broadleaf crops.

Applications

• Cereal Crops:

  • Widely used in wheat and barley for post-emergence control of grasses.

  • Effective against Alopecurus spp., Bromus spp., Lolium spp., Phalaris spp., and Avena spp.

• Timing:

  • Applied post-emergence at the early tillering stage of crops for maximum efficacy.

• Integrated Weed Management (IWM):

  • Compatible with other selective herbicides to manage resistant grass populations.

Advantages

• High Selectivity: Controls grasses without damaging wheat and barley.

• Systemic Action: Translocates within the plant for complete weed control, including underground tillers.

• Low Application Rate: Effective at very low doses (10–25 g a.i./ha).

• Resistance Management Tool: Can be used in rotation programs with herbicides from other modes of action.

• Environmental Profile: Low toxicity to mammals and minimal soil residual activity.

Specifications (Typical Parameters)

FAQ

Q1: Can Mesosulfuron-methyl be used on all cereal crops?
A: It is safe for wheat and barley, but not recommended for oats, rice, or maize.

Q2: Does it control broadleaf weeds?
A: No, it is highly selective for grasses. Broadleaf weeds require a different herbicide.

Q3: When should it be applied for best results?
A: Early post-emergence, when weeds are at the 2–4 leaf stage and crops are actively tillering.

Q4: Can it be used in integrated weed management?
A: Yes, it can be rotated with other herbicides to prevent resistance and manage mixed weed populations.

Q5: Is Mesosulfuron-methyl environmentally safe?
A: It has low mammalian toxicity, degrades rapidly in soil, and has minimal groundwater impact.

Q6: What is the application rate?
A: Typically 10–25 g a.i./ha, depending on weed pressure and crop growth stage.