Terrox Topramezone 33.6% SC Post-Emergent Herbicide for Maize by Insecticides India

Terrox is a selective post-emergence herbicide from Insecticides India Limited, containing Topramezone 33.6% SC (336 g/l). It is specifically designed for effective control of both grassy and broadleaf weeds in maize (corn) crops. Weeds like Echinochloa (Barnyard grass), Parthenium (Carrot grass), Trianthema (Horse Purslane), and Amaranthus species compete aggressively with maize for water, nutrients, and sunlight, potentially reducing yields significantly. Terrox offers a reliable, labor-saving alternative to manual weeding, which is becoming increasingly expensive and difficult to manage.

As a member of the HRAC Group 27 (HPPD inhibitor) chemistry, Terrox works by disrupting the weed's ability to produce carotenoids—essential compounds that protect the plant's chlorophyll from sunlight. When applied at the correct growth stage (2 to 5 leaf stage of weeds, typically 20–25 days after sowing), it provides rapid and visible results. Weeds begin to show a characteristic white bleaching effect within days, followed by tissue death and complete collapse. Importantly, maize plants have a natural ability to rapidly break down Topramezone, making the herbicide highly selective and safe for the crop when used as directed.

Terrox is formulated as a Suspension Concentrate (SC), which offers excellent mixing properties and rainfastness once dried on the leaf surface. For best results, it must be used with a Methylated Seed Oil (MSO) adjuvant at 2 ml per litre of water, which helps the herbicide penetrate the waxy leaf surface of weeds. It can also be tank-mixed with Atrazine 50% WP for enhanced and broader-spectrum weed control. With a pre-harvest interval (PHI) of 83 days and moderate to low toxicity classification (Blue/Green triangle), Terrox is a practical and effective tool for maize farmers seeking cleaner fields and better yields.

Key Benefits

• Rapid visible action: Weeds start turning white (bleaching) within 3–4 days of application, giving quick confirmation that the product is working.
• Selective and crop-safe: Maize plants naturally break down Topramezone, so the herbicide kills weeds without harming the crop when used at recommended doses.
• Broad-spectrum weed control: Effectively controls both grassy weeds (like Barnyard grass) and broadleaf weeds (like Parthenium, Horse Purslane, and Amaranthus) in a single application.
• Reduces dependency on manual labor: Provides a cost-effective alternative to manual weeding, which is becoming scarce and expensive in many regions.
• Flexible application window: Can be applied when weeds are at the 2 to 5 leaf stage (around 20–25 days after sowing), giving farmers a practical window for treatment.
• Good rainfastness: The SC formulation sticks well to leaves and is generally rainfast within 1–2 hours after application, reducing the risk of wash-off.
• Tank-mix compatible: Can be mixed with Atrazine 50% WP for enhanced weed control and residual activity.

How It Works

Terrox contains Topramezone, which belongs to the HRAC Group 27 class of herbicides known as HPPD inhibitors. When sprayed on weeds (along with the mandatory MSO adjuvant), Topramezone is rapidly absorbed through the leaves and roots of the target weeds. Once inside the plant, it blocks the 4-HPPD enzyme (4-hydroxyphenylpyruvate dioxygenase), which is essential for the production of carotenoids. Carotenoids act as a natural "sunscreen" for the plant's chlorophyll, protecting it from damage by sunlight. When this enzyme is blocked, the weed can no longer produce carotenoids. Without this protection, sunlight destroys the chlorophyll in the weed's leaves. This causes the weed tissue to turn white (a process called bleaching), followed by necrosis (tissue death), and eventually the complete collapse and death of the weed. The entire process is visible within a few days of application. Maize plants are naturally tolerant to Topramezone because they possess enzymes that rapidly detoxify the herbicide, breaking it down into harmless compounds before any damage can occur. This selective metabolism is what makes Terrox safe for use on maize while being highly effective against a wide range of weeds.

Technical Specifications

Parameter	Details
Brand Name	Terrox
Manufacturer	Insecticides India Limited
Active Ingredient	Topramezone 33.6% SC (336 g/l)
Formulation Type	Suspension Concentrate (SC)
HRAC Mode of Action Code	Group 27 (HPPD Inhibitor)
Chemical Group	Phenyl Pyrazolyl Ketone (Pyrazolone)
Toxicity Label	Blue/Green Triangle (Moderate to Low Toxicity)
Available Pack Size	15 ml, 30 ml
HSN Code	38089199
GST Slab	18%

Recommended Dosage & Application

Crop	Dose (ml per Acre)	Water (L per Acre)	Dose (ml per Litre)	PHI (Days)
Maize	30–40 ml	150–200 L	~0.2 ml	83

Mandatory Adjuvant (MSO): Add MSO (Methylated Seed Oil) at 2 ml per litre of water (300–400 ml per acre). Without MSO, the efficacy of Terrox drops significantly as the herbicide cannot properly penetrate the waxy leaf surface of weeds.

Optional Tank Mix: For enhanced and faster weed control, Terrox can be tank-mixed with Atrazine 50% WP at 500 g per acre. This combination provides a synergistic "burn down" effect and offers residual control against new weed germination.

Application Method: Foliar spray using Flat Fan or Flood Jet nozzles. Avoid cone nozzles as they may not provide uniform coverage.

When to Use

Timing is critical for the best results with Terrox. The ideal time to spray is when weeds are at the 2 to 5 leaf stage, which typically occurs 20–25 days after sowing maize. At this stage, weeds are young, actively growing, and most susceptible to the herbicide. Weeds that are taller than 6 inches or beyond the 5-leaf stage become much harder to control—they may only be stunted or temporarily bleached and could recover. For best absorption and activity, ensure the soil has adequate moisture at the time of spraying. Avoid spraying if rain is imminent; however, once the spray has dried on the leaves (usually within 1–2 hours), the product is generally rainfast. Do not apply under extreme heat or drought stress conditions, as this may reduce effectiveness.

Step by Step Usage Instructions

1. Check weed stage: Walk your field and confirm that most weeds are at the 2 to 5 leaf stage (not taller than 6 inches). This is usually 20–25 days after sowing maize.
2. Prepare the spray solution: Fill the spray tank with half the required amount of clean water. Add the measured quantity of Terrox (30–40 ml per acre) and mix well. Then add MSO adjuvant at 2 ml per litre of water (300–400 ml per acre). If using Atrazine tank mix, add 500 g of Atrazine 50% WP per acre. Top up with remaining water and mix thoroughly.
3. Select the right nozzle: Use Flat Fan or Flood Jet nozzles for uniform spray coverage. Avoid cone nozzles.
4. Spray evenly: Apply the mixture as a uniform foliar spray, ensuring complete coverage of the weed foliage. Use 150–200 litres of water per acre.
5. Post-application care: Do not enter the treated field for at least 24 hours after spraying (re-entry period). Wash the spray equipment thoroughly after use. Do not drain leftover spray solution near water bodies.

Compatibility

Terrox is compatible and recommended for tank mixing with Atrazine 50% WP at 500 g per acre for enhanced weed control and residual activity. The use of MSO (Methylated Seed Oil) adjuvant at 2 ml per litre of water is mandatory for effective weed penetration and efficacy. Always follow the correct mixing sequence: first add water, then the adjuvant, then the herbicide, and finally the tank-mix partner if used. If compatibility with any other product is uncertain, perform a small jar test before large-scale mixing.

Precautions & Safety

• Personal Protective Equipment (PPE): Always wear gloves, mask, and goggles while handling and spraying Terrox. Wear full protective clothing during application.
• Do not eat, drink, or smoke while handling or spraying the product.
• Keep away from foodstuffs and animal feed. Store the product in a cool, dry place out of reach of children.
• Avoid contact with mouth, eyes, and skin. Do not inhale the spray mist.
• Wash thoroughly after handling—wash hands, face, and all exposed body parts with soap and water. Wash contaminated clothing separately before reuse.
• Environmental safety: Prevent discharge of spray solution or rinsate into lakes, ponds, streams, and water bodies. Do not reuse empty containers—puncture and dispose of them safely.
• Re-entry period: Do not enter treated fields for at least 24 hours after spraying.

Side Effects & Phytotoxicity

Terrox is specifically formulated for use on maize and is highly selective when used as directed. Maize plants naturally detoxify Topramezone rapidly, so crop injury is not expected at recommended doses. However, spraying on crops other than maize, or using higher than recommended doses, may cause damage. Weeds sprayed beyond the 5-leaf stage or taller than 6 inches may only show temporary bleaching and could recover. Always follow the recommended dosage and application timing to avoid reduced efficacy.

PHI / REI & Storage

• Pre-Harvest Interval (PHI): 83 days after application
• Re-Entry Interval (REI): 24 hours after spraying
• Storage: Store in a cool, dry place away from foodstuffs, animal feed, and out of reach of children. Keep the container tightly closed when not in use.