Ametryn: A Selective Pre- and Post-Emergent Herbicide

Definition:
Ametryn is a selective triazine herbicide used primarily for controlling broadleaf and grassy weeds in crops such as sugarcane, maize, potatoes, and certain vegetables. It can be applied as both a pre-emergent and post-emergent herbicide, offering residual soil activity and foliar contact control.

Chemical Characteristics of Ametryn:

• Chemical Name: 2-(Ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine

• Molecular Formula: C₉H₁₇N₅S

• Molecular Weight: 227.3 g/mol

• Appearance: White to beige crystalline solid.

• Solubility: Slightly soluble in water; soluble in organic solvents.

• Stability: Stable under normal conditions; degrades slowly in soil through microbial activity.

Mode of Action:

Ametryn inhibits photosystem II (PSII) by blocking electron transport during photosynthesis, leading to reduced energy production and eventual plant death. It is absorbed through roots and foliage and translocated within the plant.

Uses and Applications:

1. Target Weeds:

   • Controls annual broadleaf weeds (e.g., pigweed, lambsquarters, ragweed).

   • Suppresses annual grasses (e.g., foxtail, crabgrass).

2. Crops:

   • Commonly used in sugarcane, maize, potatoes, pineapple, cassava, bananas, and some legumes.

3. Application Timing:

   • Pre-emergence: Applied to soil before weed germination.

   • Post-emergence: Applied to young, actively growing weeds.

Benefits of Ametryn:

• Dual Action: Effective both pre- and post-emergence.

• Residual Control: Provides prolonged weed suppression in crops like sugarcane.

• Crop Selectivity: Safe when applied at recommended rates to tolerant crops.

• Tank-Mix Flexibility: Can be combined with other herbicides to broaden spectrum.

Limitations:

• Soil Dependence: Efficacy influenced by soil type and organic matter.

• Resistance Risk: Long-term use may lead to PSII inhibitor-resistant weeds.

• Environmental Concerns: Potential leaching in sandy soils and risk to aquatic ecosystems.

Recommended Application:

• Dosage: Typically 1.0–3.0 kg active ingredient per hectare depending on crop and soil conditions.

• Method: Ground or aerial spraying, ensuring good coverage.

• Precautions:

  • Apply before heavy rainfall to prevent runoff.

  • Rotate with herbicides of different modes of action.

  • Avoid drift onto sensitive crops and water bodies.

Storage and Handling:

• Storage: Store in a dry, cool, ventilated location away from food and feed.

• Shelf Life: 2–3 years under proper storage conditions.

• Safety: Use protective equipment; avoid inhalation and skin contact.

FAQ on Ametryn:

Q1: What is Ametryn primarily used for?
A1: It is mainly used in sugarcane and maize to control broadleaf and grassy weeds.

Q2: Does Ametryn have residual soil activity?
A2: Yes, it provides residual control for several weeks after application.

Q3: Can Ametryn be used on all crops?
A3: No, it is crop-selective and suitable only for tolerant crops listed on the label.

Q4: How is resistance to Ametryn managed?
A4: Rotate with herbicides of different modes of action and integrate with cultural weed control methods.