HPM Benister Bispyribac Sodium 10% SC Herbicide - Selective Post-Emergence Weed Control for Rice

HPM Benister is a selective, systemic post-emergence herbicide containing Bispyribac Sodium 10% SC (Suspension Concentrate). It is specifically designed to control a broad spectrum of grasses, sedges, and broad-leaved weeds in rice crops. The herbicide is absorbed through both the foliage and roots of weeds, providing thorough and effective weed suppression.

HPM Benister is primarily recommended for use in Direct-Seeded Rice (DSR) and can also be used in transplanted rice and rice nurseries. It targets major problem weeds like Barnyard Grass (Echinochloa spp.), Umbrella Sedge (Cyperus difformis), and other broad-leaved weeds such as Monochoria and Ludwigia species. By controlling weeds at an early stage, it helps rice plants establish better, reduces competition for nutrients and sunlight, and ultimately supports higher crop yields. The product belongs to the Pyrimidinyl carboxy herbicide chemical group and is classified under IRAC Mode of Action Group 2 (ALS Inhibitor). It carries a Blue Label toxicity classification (moderately toxic) and should be handled with standard safety precautions.

Key Benefits

• Selective action for rice: Targets harmful weeds without damaging the rice crop when used as per recommended dosage.
• Systemic control from both sides: Absorbed through leaves and roots, ensuring thorough weed suppression from top to bottom.
• Broad-spectrum weed management: Controls grasses (Echinochloa), sedges (Cyperus), and broad-leaved weeds in a single application.
• Quick visible results: Weeds stop growing immediately after application, with complete death visible within 7–14 days.
• Reduces labour dependency: Minimises the need for manual weeding, saving time and labour costs during critical crop stages.
• Rainfast in 6 hours: Quickly absorbed by weed foliage, so light rain after 6 hours does not reduce effectiveness.
• Flexible application window: Can be applied from nursery stage up to 25 days after sowing when weeds are at 2–5 leaf stage.

How It Works

HPM Benister works as an ALS (Acetolactate Synthase) inhibitor. When sprayed on weeds, the active ingredient Bispyribac Sodium is absorbed through the leaves and also taken up by the roots. Once inside the weed, it blocks the production of essential amino acids—valine, leucine, and isoleucine—that are critical for plant growth and survival.

Without these amino acids, the weed stops growing almost immediately after application. Within a few days, the leaves begin to turn yellow (chlorosis) and then brown (necrosis), leading to complete weed death within 7–14 days. The rice crop remains safe because it possesses natural enzymes that break down the chemical before it can cause harm. This selective metabolism is what makes HPM Benister effective against weeds while being safe for paddy.

Technical Specifications

Recommended Dosage & Application

Application Method: Foliar spray using a Knapsack sprayer fitted with a Flat Fan or Flood Jet nozzle for uniform coverage.

When to Use

Apply HPM Benister when weeds are at the 2 to 5 leaf stage for best results. This is typically 15–25 days after sowing in Direct-Seeded Rice (DSR) or 10–14 days after transplanting in transplanted rice. Early application when weeds are young and actively growing gives the best control. Do not apply if rain is expected within 6 hours, as the product needs this time to be fully absorbed by weed leaves. Ensure the soil is moist (saturated) but not flooded at the time of application.

Step by Step Usage Instructions

• Step 1 – Drain water: Drain standing water from the field so that weed leaves are fully exposed for spray coverage.
• Step 2 – Prepare spray solution: Mix the recommended dose of HPM Benister in clean water as per the dosage table. Use a Flat Fan or Flood Jet nozzle for best results.
• Step 3 – Spray uniformly: Apply the spray solution evenly over the field, ensuring thorough coverage of all weed foliage.
• Step 4 – Re-flood after 48–72 hours: After spraying, wait for 2–3 days and then re-flood the field with water. This helps suppress any new weed germination.
• Step 5 – Post-application care: Avoid entering the sprayed area until the spray solution has dried. Wash spray equipment thoroughly after use.

Precautions & Safety

• Wear personal protective equipment (PPE) including gloves, mask, and goggles during mixing and spraying.
• Avoid direct contact with skin, eyes, and inhalation of spray mist.
• Do not spray near ponds, canals, or aquaculture zones as Bispyribac Sodium can be toxic to aquatic life.
• Store in a cool, dry place away from food, feed, and children.
• Wash hands and exposed skin thoroughly after handling the product.
• Do not eat, drink, or smoke while mixing or spraying.
• Rinse spray equipment thoroughly after use and dispose of wash water safely away from water bodies.

PHI / REI & Storage