What Is Metribuzin and How Is It Used in Agriculture?

Metribuzin is a selective triazinone herbicide widely applied for controlling broadleaf weeds and some grasses. It is commonly used in crops such as soybeans, potatoes, tomatoes, alfalfa, and sugarcane.

Composition

• Chemical name: 4-amino-6-tert-butyl-3-(methylthio)-1,2,4-triazin-5(4H)-one

• Molecular formula: C₈H₁₄N₄OS

• Appearance: Off-white crystalline solid

• Mode of action: Inhibits photosystem II, blocking electron transport during photosynthesis, which causes weeds to die.

Key Features

• Effective against a wide spectrum of annual broadleaf weeds and grasses.

• Can be applied pre-emergence or post-emergence, depending on the crop and target weeds.

• Compatible with tank mixtures for broader weed control.

• Provides residual soil activity, reducing follow-up herbicide applications.

Applications

• Soybeans: Controls pigweed, lambsquarters, and foxtail.

• Potatoes: Reduces nightshade and common broadleaf weed competition.

• Tomatoes: Effective in field-grown crops against purslane, amaranth, and barnyard grass.

• Alfalfa & Sugarcane: Used for early-season weed management.

Specifications

• Formulations: 70% WDG (water dispersible granule), 480 g/L SC (suspension concentrate), 70% WP (wettable powder).

• Dosage: Typically 0.2–1.5 kg/ha, depending on crop and soil type.

• Persistence: Moderate soil persistence (half-life 30–60 days).

Advantages

• Broad-spectrum weed control with both soil and foliar activity.

• Helps protect crop yield by minimizing early weed competition.

• Flexible application timing (before or after crop emergence).

Limitations

• Crop injury risk on sandy soils with low organic matter.

• Reduced effectiveness on deep-rooted perennial weeds.

• Environmental concerns: potential to leach into groundwater in sandy soils.

FAQs

Q1: Is Metribuzin safe for all crops?
No. Certain crops like cucumbers or peppers are sensitive and may be injured by Metribuzin. Always check crop-specific guidelines.

Q2: Can it be mixed with other herbicides?
Yes. Often tank-mixed with glyphosate, metolachlor, or pendimethalin for broader spectrum control.

Q3: How long does Metribuzin remain active in soil?
Its activity usually lasts 4–8 weeks, depending on soil type, temperature, and moisture.

Q4: Is there resistance to Metribuzin?
Yes. Some weed populations have developed resistance due to overuse, so rotation and mixtures are recommended.