Chemical Class and Mode of Action
Metribuzin belongs to the triazinone chemical class (HRAC Group 5), functioning as a Photosystem II (PS II) electron transport inhibitor.
It binds to the D1 protein of the photosystem II reaction center in weed chloroplasts, blocking electron flow and generating destructive singlet oxygen radicals that destroy cell membranes.
- Triazinone Selective Chemistry: Highly effective against broadleaf weeds and annual graminaceous grasses
- Dual Uptake: Absorbed primarily through weed roots and emerging hypocotyls, with translaminar foliar penetration
- Acropetal Translocation: Moves rapidly upward through xylem vessels, concentrating in weed leaf margins and growing tips
Target Crops and Application Timing
Metribuzin 70% WP is registered across diverse field and vegetable crops with tailored application windows.
In sugarcane and potato, it establishes an effective pre-emergence chemical barrier on the soil surface that kills germinating weed seeds.
- Sugarcane: Applied pre-emergence or early post-emergence to manage mixed grass and broadleaf flushes
- Potato: Applied pre-emergence after ridge planting or early post-emergence when potato plants are 5 to 10 cm tall
- Soybean: Applied pre-emergence within 24 to 48 hours after sowing on well-prepared moist seedbeds
- Wheat: Post-emergence application (30 to 35 days after sowing) targeting isoproturon-resistant Phalaris minor (Gullidanda)
Soil Moisture and Varietal Safety Safeguards
Herbicide activation requires adequate soil moisture at the time of application.
Avoid applying metribuzin on coarse, light sandy soils with low organic matter (< 0.5%), as excessive root leaching can cause temporary crop chlorosis.
- Soil Moisture Requirement: Apply only when topsoil is moist; dry soil reduces root absorption and weed control efficacy
- Water Volume: Use at least 200 liters of water per acre with flat-fan nozzles for uniform ground coverage
- Varietal Sensitivity: Check crop cultivar labels, as certain sensitive soybean or potato cultivars may exhibit mild transient stunting
Official source
Check the latest rules, benefits and forms here. KisanPe is an independent platform and is not a government website.
Central Insecticides Board & Registration Committee ↗Related on KisanPe
Common questions
What weeds are controlled by metribuzin 70% WP?
It controls broadleaf weeds (Chenopodium, Amaranthus, Portulaca) and annual grasses (Phalaris minor, Digitaria, Echinochloa).
What is the mode of action of metribuzin?
It inhibits Photosystem II (PS II) in weed chloroplasts, halting photosynthetic electron flow and causing cell chlorosis and necrosis.
When is metribuzin applied in potato crops?
It is typically applied pre-emergence immediately after ridge formation, or early post-emergence when potatoes are up to 5 to 10 cm tall.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
More Crop Protection & Pesticides guides
Ask Sakhi AI in your language, check live mandi prices or plan a loan with KisanPe tools.