Imazethapyr 35% + Imazamox 35% WG Herbicide Uses

Imazethapyr 35% + Imazamox 35% WG is a ready-mix, selective, post-emergence herbicide combining two actives of the imidazolinone group — imazethapyr and imazamox — registered for use in India under the Insecticides Act, 1968, formulated as water-dispersible granules (WG). It is registered, with a methylated seed oil (MSO) adjuvant, for the control of grassy and broadleaf weeds such as sanwak, para grass, kankawa, dudhi, chaulai and tandla in soybean, groundnut, cluster bean and red gram (arhar). This page lists its mode of action, key benefits and the recommended dosage as per the Central Insecticides Board & Registration Committee (CIB&RC) official list of approved herbicide uses (Government of India).

Which Weeds Does This Control? (Field Identification Guide)

Not sure whether the weeds in your field match this herbicide's use case? This guide helps match weed identification to this herbicide's approved crop-wise uses.

Mode of Action

Both imazethapyr and imazamox are imidazolinone herbicides that inhibit acetolactate synthase (ALS, also called AHAS) — HRAC Group 2 (formerly Group B). They are absorbed through the leaves and roots and move to the growing points, where blocking ALS stops the production of the branched-chain amino acids valine, leucine and isoleucine. Weed growth stops within a few days; the youngest leaves turn yellow or purplish and the weeds die over about 2–3 weeks.

The two actives share the same mode of action (Group 2), so the combination does not add a second mode of action. It is used because the two partners complement each other: imazamox has quicker foliar activity, while imazethapyr also gives some residual activity through the soil, which together broaden and steady the weed spectrum controlled. The MSO adjuvant registered with the product improves leaf wetting and uptake.

Features & Benefits

• Controls both grassy weeds (sanwak, viper grass, crabgrass, para grass and other Brachiaria grasses) and broadleaf weeds (kankawa, dudhi, chaulai, tandla, chirpoti, bishkhapra) in a single post-emergence spray.
• Registered for four kharif legume crops — soybean, groundnut, cluster bean and red gram (arhar).
• Very low dose per acre in a water-dispersible granule (WG) formulation.
• Systemic action through leaves and roots, with some soil activity from the imazethapyr component.
• Both components are Group 2 (ALS inhibitors) — rotate with herbicides of other groups, such as pre-emergence herbicides, as part of an integrated weed-management program.

Recommended Usage of Imazethapyr 35% + Imazamox 35% WG Herbicide

The table below gives the recommended dose, water volume and waiting period per acre for each crop, converted from the CIB&RC-registered per-hectare rate — see the note below the table for conversion details. Always spray in the recommended water volume for uniform coverage, and confirm against the current product label before use.

Figures above are converted from the CIB&RC-registered per-hectare rates (1 ha ≈ 2.47 acres): Soybean — 70 g a.i./ha, 100 g formulation/ha, 375–500 L water/ha, waiting period 56 days; Groundnut — 70 g a.i./ha, 100 g formulation/ha, 375–500 L water/ha, waiting period 83 days; Cluster bean — 70 g a.i./ha, 100 g formulation/ha, 500 L water/ha, waiting period 64 days; Red gram — 70 g a.i./ha, 100 g formulation/ha, 375–500 L water/ha, waiting period 125 days; for every crop CIB&RC registers the dose together with an MSO adjuvant @ 2 ml/litre of water. *The MSO adjuvant is a fixed mixing concentration (2 ml in every litre of spray solution), not a per-acre rate, so the total adjuvant quantity depends on the spray volume actually used. Always confirm the current product label before use.

How to Use

1. Identify the weeds in your field using the guide above and confirm that the crop and weeds match the approved uses.
2. Spray post-emergence, when the weeds are young (generally at the 2–4 leaf stage) and actively growing; follow the product label for the exact timing in your crop.
3. Make a slurry of the measured granules in a little water, pour it into a half-filled spray tank, add the MSO adjuvant at 2 ml per litre of the total spray volume and top up with clean water while stirring.
4. Use a knapsack sprayer with a flat-fan nozzle and cover the weeds uniformly; do not overlap spray swaths.
5. Spray when the soil has adequate moisture and no rain is expected for several hours.
6. Clean the sprayer thoroughly after use before using it on any other crop.

Precautions & Safety

• Respect the waiting period (PHI) between spraying and harvest: soybean 56 days, groundnut 83 days, cluster bean 64 days and red gram 125 days.
• Imidazolinone herbicides can persist in the soil; check the product label for the crops that can safely be sown after treatment, as sensitive following crops may be injured.
• Avoid spray drift onto neighbouring sensitive crops, and do not use in crops other than those registered by CIB&RC.
• Both components belong to herbicide Group 2; do not rely on this or other Group 2 herbicides alone season after season — rotate or combine with other groups and weed-control methods to slow resistance development.
• Wear appropriate PPE — mask, gloves, goggles and full-sleeved clothing — while mixing and spraying, and avoid inhaling the spray mist.
• Do not let spray, spray-tank washings or leftover solution reach ponds, canals, streams or drinking-water sources.
• Store in the original, tightly closed container in a cool, dry place away from direct sunlight, food and feed, and out of reach of children and livestock.
• Wash hands, face and any exposed skin thoroughly with soap and water after spraying, and change out of contaminated clothing before eating, drinking or smoking.

Brand names mentioned on this page are registered trademarks of their respective owners and are referenced here for identification purposes only; FarmMate is not affiliated with or endorsed by these brands. This page is for general information only — always consult your local agricultural extension office and confirm the current product label before use.