TOPMAX 400 SC is a selective post-emergence herbicide for maize that combines the rapid knockdown of Topramezone with the residual activity of Terbuthylazine. Its dual-action formulation ensures that both emerged weeds and germinating seedlings are effectively controlled, leading to enhanced crop establishment and early vigor.
The formulation is designed for rapid uptake through leaves and roots, with uniform translocation to growing points.
Topramezone 30 g/L + Terbuthylazine 370 g/L
SC (Suspension concentrate)
HRAC 27 (HPPD inhibitor – Topramezone) + 5 (Photosystem II inhibitor – Terbuthylazine)
Foliar spray
1.5–2.0 litres per hectare
12 hours
Topramezone blocks an enzyme the weed needs to protect its chlorophyll from breaking down in sunlight, so treated weeds bleach white as their pigment is destroyed, then die as the tissue can no longer photosynthesise, visible within a week. Terbuthylazine works differently, blocking the photosynthesis process itself at the point where the plant converts light into usable energy, which also gives it real residual activity in the soil against germinating weeds.
Together, one gives a fast bleaching kill on emerged weeds and the other adds a longer soil-active barrier.
Recommended rate: 1.5–2.0 litres per hectare
| Crop | Target | Timing | Max |
|---|---|---|---|
| Maize | Broadleaf weeds | Post-emergence | 3 |
Apply once weeds have emerged, this product's HPPD component needs actively growing tissue to work on, but the terbuthylazine side then continues protecting against new germination for weeks afterward, which is real value on a longer-season crop like maize. Because terbuthylazine is soil-residual and can persist meaningfully, check plant-back restrictions before switching to a more sensitive rotational crop on the same ground next season.
Maize tolerates both actives well due to how quickly it metabolises them, which is what makes this combination selective in the first place.
Wear chemical-resistant gloves and eye protection when handling the concentrate. Store in the original container away from direct sunlight, children, food, and livestock.
Triple-rinse containers before disposal.
Registered for use on labelled crops across East African markets, under the relevant national regulatory authority. Always read and follow the approved product label before use.
