Tribenuron-methyl

Tribenuron-methyl is a systemic, selective herbicide belonging to the sulfonylurea chemical class. It is primarily absorbed through the leaves and translocated throughout the plant via the xylem and phloem.

The mode of action is the inhibition of the enzyme acetolactate synthase (ALS). By blocking this key enzyme, the herbicide prevents the biosynthesis of essential branched-chain amino acids, specifically valine, leucine, and isoleucine.

Inhibition of amino acid synthesis leads to a cessation of cell division and plant growth shortly after application. Death of susceptible weed species occurs within a period of 10 to 25 days depending on the growing conditions.

Crop selectivity is achieved through rapid metabolic degradation of the active ingredient into inactive metabolites within cereal plants, ensuring that the crop remains unaffected.

The efficacy of the substance is highly stable across different soil textures, as its primary pathway of uptake is foliar absorption rather than root uptake from the soil.

The herbicide is widely used for the control of a broad spectrum of annual and perennial broadleaf weeds. It is especially valued for controlling weeds that have developed resistance to other common herbicide groups.

• Cirsium arvense (Canada thistle)
• Sonchus arvensis (Perennial sowthistle)
• Chenopodium album (Common lambsquarters)
• Stellaria media (Chickweed)
• Sinapis arvensis (Wild mustard)
• Papaver rhoeas (Common poppy)

Standard application rates usually range from 15 to 50 grams of active ingredient per hectare. The optimal timing for application is during the tillering stage of the cereal crop.

To ensure maximum effectiveness, applications should target weeds in their early stages of development, specifically when they have 2 to 4 true leaves. Larger weeds may require higher dosages or different chemical partners.

Do not apply the herbicide to crops under environmental stress, such as drought, extreme cold, or flooding, as this may reduce crop selectivity and potentially lead to transient phytotoxicity.

Application should be avoided when temperatures exceed 25°C. Always ensure that the sprayer is properly cleaned after use, as residues can be harmful to sensitive broadleaf crops in subsequent rotations.