Weeds, control & management
Effective weed control is essential for optimizing maize yields, particularly during the initial 6 to 10 weeks post-planting when competition for nutrients, water, and light is most intense. Failure to manage weeds during this critical period can result in yield reductions exceeding 50%. Additionally, allowing weeds to seed increases the soil's weed seed bank, complicating future control efforts.
In Zimbabwe, over 20 herbicides are registered for maize cultivation, many suitable for application directly over the crop. Pre-emergence herbicides, such as Atrazine and Dual, are applied before or shortly after crop emergence to prevent weed establishment. Post-emergence herbicides, including Stellar Star and Auxo, target weeds that have already emerged, ensuring continued crop dominance.
Selecting the appropriate herbicide and application timing is crucial for effective weed management. Farmers should consider factors such as weed species present, crop growth stage, and environmental conditions to optimize herbicide efficacy and minimize potential crop injury.
Integrating chemical control with cultural practices, such as crop rotation and mechanical weeding, can enhance weed management strategies. This integrated approach reduces reliance on herbicides, mitigates the risk of herbicide resistance, and promotes sustainable maize production.
There are more than 20 herbicides registered on maize in Zimbabwe, most of which can be sprayed on top of the maize crop.[1]
| Herbicide Name | Active Ingredient | Rate/Ha | Time of application |
| Atrazine | Triazine | 3l/ha | Pre and Early Post-emergence |
| Dual | S- Metalachlor 960g/l and 40g/l inert matter | 1-1.5l/ha | Pre-emergence |
| Lasso | Alachlor 480g/l. Inert ingredients 520g/l. | 2.8-3.5l/ha | Pre-emergence |
| Bateleur Gold 650EC | Flumetsulam (sulfonanilide), s – metalachlor | 0.7-1.7l/ha | Pre-emergence |
| Stellar Star | Topramezone (pyrasolone), Dicamba (benzoic acid compound) | 1l/ha | Post-emergence |
| Auxo | Tembotrione, Bromoxynil Octanoate and Isoxadifen-ethyl safener | 1.5l/ha | Post-emergence |
| Russel | Pot-emergence | ||
| Maximus | Terbuthylazine, Mesotrione and Metalachor | 2l/ha | Post-emergence |
| Rimex | 60g/ha | Post-emergence | |
| MCPA | MCPA | Post-emergence | |
| Revolt | Dicamba and Nicosulfuron | 500g/ha | Post-emergence |
| Frontier Optima | Dimethenamid | 1-1.25l/ha | Pre-emergence |
| Armadillo | Sulcotrione (triketone), Atrazine (triazine), related triazine | 1l/ha | Pre and early Post-emergence |
| Galago | Mesotrione (triketone) 480g/l | 260ml/ha | Pre and Post-emergence |
| Prowl CS | Pendimethalin Chemical group- dinitroaniline | 3l/ha | Pre and early Post |
| Servian | Halosulfuron | 50g/ha | Post-emergence (Nutsedge) |
| Accent | Nicosulfuron | 45g/ha | Post-emergence (Shamva) |
References
- ^ Arlington. “Weed Control - Seed Co Zimbabwe | Field Crops.” Seed Co Zimbabwe | Field Crops, 24 Jan. 2023, SeedCogroup Zw
Weeds control - Cropserve
| Weed Control Type | Target Weeds | Product Name | Active Ingredient |
|---|---|---|---|
| Pre-Plant Clean Up (Non-Selective) | Annual and Perennials Weeds including Couch and Stargrass | Glyphon 700 WSG | Glyphosate |
| Pre-Emergent Herbicides (Selective) | Broadleaf Weeds plus Rapoko | Atrazine 50 FW | Atrazine |
| Pre-Emergent Herbicides (Selective) | Annual Grasses, Nutgrass & Most Broadleaf Weeds | Frontier Optima | Dimethanamid-P |
| Pre-Emergent Herbicides (Selective) | Annual Grasses, Nutgrass Suppression & Some Broadleaf | Dual Magnum 960 EC, Rush 960 EC | s-Metolachlor, Acetochlor |
| Post-Emergent Herbicides (Selective) | Broadleaf Weeds plus Rapoko | Atrazine 50 FW | Atrazine |
| Post-Emergent Herbicides (Selective) | Emerged Broadleaf Weeds | Bromatril 500, MCPA | |
| Post-Emergent Herbicides (Selective) | Shamva Grass & Some Broadleaf Weeds (Wheat Re-growth @ 60g) | Arrow 75 WDG | Nicosulfuron |
| Post-Emergent Herbicides (Selective) | Nutgrass & Some Broadleaf Weeds | Halosulfuron 75 WDG | Halosulfuron |
| Post-Emergent Herbicides (Selective) | Emerged Broadleaf and Grass Weeds (Inc. Couch) | Stellar Star | Topramazone + Dicamba |
| Post-Emergent Herbicides (Selective) | Most Broadleaf Weeds, Some Grasses & Nutsedge | Rimex 25 WDG | Rimsulfuron |
| Post-Emergent Herbicides (Selective) | Emerged Broadleaf Weeds, Most Grasses & Nutsedge | Maximus 537.5 SE | Metalachlor, Terbuthylazine & Mesotrione |
| Post-Emergent Herbicides (Selective) | Emerged Broadleaf Weeds, Grasses (Inc Shamva & Wheat) & Nutgrass | Russel 260 OD | Nicosulfuron, Terbuthylazine & Mesotrione |
References
-
“Maize - Cropserve.” Cropserve, 3 Nov. 2020, Cropserve.
- Title
- Weeds, control & management
- Description
- Weeds, Control and Management: Identification and management strategies for problematic weeds in regional farming systems, including cultural, mechanical, and chemical control methods suitable for local conditions.
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