HPM Benpret Herbicide - Pretilachlor 6% + Bensulfuron Methyl 0.6% GR for Paddy Weed Control

Benpret is a pre-emergence granular herbicide manufactured by HPM Chemicals & Fertilizers Ltd., specially designed for transplanted paddy (rice). It combines two powerful active ingredients — Pretilachlor 6.0% and Bensulfuron Methyl 0.6% — in a ready-mix granule (GR) formulation. This dual-action herbicide provides broad-spectrum control of grasses, sedges, and broadleaf weeds during the critical first month of rice growth.

Benpret is applied within 0 to 5 days after transplanting, directly into standing water. The granules dissolve and form a chemical barrier on the soil surface. As weeds try to emerge, they absorb the active ingredients through their roots and shoots, which stops their growth before they can compete with the rice crop. This early protection helps farmers reduce manual weeding labor significantly and ensures the paddy seedlings establish without competition for nutrients, sunlight, and space.

The product comes in a convenient 4 kg pack, which is the exact dose required for 1 acre of transplanted rice. It carries a Blue Triangle toxicity label (Slightly Hazardous) and has a pre-harvest interval (PHI) of 88 days. Benpret is not recommended for use in fields where fish culture is practiced, as Pretilachlor is toxic to aquatic life.

Key Benefits

• Reduces manual weeding labor by over 90% — Replaces 15-20 labor days per hectare, saving significant time and money compared to manual weeding costs of ₹6,000–₹8,000 per hectare.
• Dual-action broad-spectrum control — Two different active ingredients work together to control grasses, sedges, and broadleaf weeds simultaneously, covering gaps that single-molecule herbicides may miss.
• Long-lasting protection up to 30-40 days — Provides a weed-free window during the critical establishment phase, allowing rice seedlings to grow strong without competition.
• Easy granular application — No spray pump required. Simply mix with sand and broadcast by hand into standing water. Simple and practical for farmers.
• Crop-safe and selective to rice — When used as directed, Benpret kills weeds without harming the paddy crop, keeping the field healthy and green.
• Cost-effective weed management — Significantly lower cost compared to manual weeding, making it an economical choice for large-scale paddy farming.

How It Works

Benpret uses a synergistic "double-engine" approach that attacks weeds through two different biological pathways, ensuring comprehensive control.

Pretilachlor (Stops Cell Division): This component is absorbed by the shoots of emerging grass weeds. It inhibits the synthesis of Very Long Chain Fatty Acids (VLCFA), which are essential for cell membrane formation. By blocking this process, Pretilachlor effectively stops cell division in emerging grass shoots, preventing them from growing further.

Bensulfuron Methyl (Halts Protein Production): This systemic component is absorbed through the roots and leaves of weeds. It inhibits the ALS (Acetolactate Synthase) enzyme, which is critical for producing essential amino acids. Without these amino acids, the weed cannot produce proteins and starves to death. This mode of action is highly effective against sedges and broadleaf weeds.

Combined Effect: When the granules are broadcast into standing water, they dissolve and form a chemical barrier on the soil surface. As weed seeds germinate and try to emerge, they absorb both active ingredients through their roots and shoots. Weeds stop growing almost immediately, with signs of yellowing appearing quickly, followed by complete death within 1-2 weeks. The combination of VLCFA inhibition and ALS inhibition ensures that even resistant weed populations are effectively controlled.

Technical Specifications

Recommended Dosage & Application

Note: The 4 kg pack is the exact dose for 1 acre of transplanted paddy. No measuring or calculation is needed — simply use one full pack per acre.

When to Use

Benpret is a pre-emergence herbicide, which means it works best when applied before weeds emerge from the soil. The ideal application window is strictly between 0 to 5 days after transplanting rice seedlings. During this period, weed seeds in the soil are just beginning to germinate but have not yet emerged with 2-3 leaves. Applying within this window ensures the chemical barrier is in place when weeds try to sprout, killing them at the most vulnerable stage.

If application is delayed beyond 5-7 days, weeds may already have developed 2-3 leaves and become more resistant to the herbicide. The effectiveness drops significantly once weeds are established. For best results, apply Benpret as soon as possible after transplanting, ideally within the first 2-3 days.

The field should have 2-3 inches (5-7 cm) of standing water at the time of application. This water layer is essential because it helps the granules dissolve evenly and spread the active ingredients across the soil surface. After application, retain this water for 2-3 days without draining to allow the granules to fully dissolve and form a protective layer on the soil.

Step by Step Usage Instructions

1. Prepare the field: After transplanting paddy seedlings, ensure the field has 2-3 inches (5-7 cm) of standing water. The water should be still (not flowing) for best results.
2. Mix with sand: Take one full 4 kg pack of Benpret granules. Mix it thoroughly with 6-10 kg of dry sand (or up to 15 kg of sand for more uniform distribution). The sand acts as a carrier to help you spread the granules evenly across the entire acre.
3. Broadcast uniformly: Walk through the field and broadcast (throw) the sand-granule mixture by hand as evenly as possible across the entire area. Make sure no spots are missed.
4. Retain water: Do not drain or disturb the water in the field for at least 2-3 days after application. This allows the granules to dissolve and form a protective chemical barrier on the soil surface.
5. Post-application care: After 2-3 days, normal water management can resume. The herbicide will remain active in the soil for approximately 30-40 days, providing continued protection against emerging weeds.
6. Safety during application: Always wear gloves, a mask, and goggles while handling and applying the product. Wash hands and exposed skin thoroughly with soap and water after application.

Precautions & Safety

• Personal Protective Equipment (PPE): Always wear gloves, a mask, and goggles while handling and applying Benpret. Avoid direct contact with skin and eyes.
• Hygiene: Wash hands and all exposed skin thoroughly with soap and water after handling the product. Do not eat, drink, or smoke during application.
• Fish toxicity: Do not use Benpret in fields where fish culture (pisciculture) is practiced. Pretilachlor is toxic to freshwater fish such as Rohu and Carp.
• Environmental safety: Prevent runoff from entering ponds, rivers, or other water bodies. Do not contaminate water sources during mixing or application.
• Storage: Store the product in a cool, dry place away from food, feed, and children. Keep in original container with lid tightly closed.
• Disposal: Do not reuse empty containers for storing food or water. Dispose of containers safely according to local regulations.

PHI / REI & Storage

Pre-Harvest Interval (PHI): 88 days for transplanted rice. This is the minimum number of days that must pass between the last application and harvesting to ensure the crop is free of chemical residues.

Shelf Life: Store in original packaging in a cool, dry place away from direct sunlight and moisture. Use before the expiry date mentioned on the product label.