Wheat is a second most important staple food crop in India, widely cultivated across the country. Weeds are plants that are considered unwanted or undesirable in a particular area. Weed infestation is a major factor limiting crop productivity as they interfere with the growing crop for nutrient, light and water requirement. Wheat is affected by both grasses and broad-leaved weeds. If weeds are not controlled from early stages of crop growth, depending upon the intensity and type of weeds, these may cause reduction in yield of wheat crop up to 40%. Integrated weed management practices need to be focused to effectively manage the weeds in any crop.
Major Weeds in Wheat Field
Both monot and dicot weeds are prevalent in wheat fields. Monocot weeds or grasses are characterized by long, narrow leaves that typically have parallel veins. While dicot or broad-leaved leaves are characterized by wider leaves that have branching veins.
| Type of weed | Weed species |
| Monocot weeds | Phalaris minor, Avena fatua, Polypogon monspllensis, Cyperus rotundus, Cynodon dactylon |
| Dicot weeds | Chenopodium album, Fumaria purviflora, Cirsium arvense, Anagalis arvensis, Melilotus alba, Melilotus indica, Vicia sativa, Lathyrus spp |
Methods of Weed Management in Wheat Field
Cultural Management:
- Crop rotation with non-host crops such as legumes, barley and corn can help break the weed life cycle.
- Providing adequate nutrients to the wheat crop can help it grow more vigorously, which can help it compete more effectively with weeds.
- Adjusting the sowing of the crops can be effective. For example, early planting of wheat can reduce Phalaris minor intensity.
- Using higher seed rates for sowing and closer row spacing may increase the plant density and suppress the weed growth.
- Mulching the wheat field with straw or other organic materials.
- Ploughing the soil before cultivation may help to place the weed seeds in the deeper soil layers which will not germinate unless brought near to the soil surface.
- Ensure to use clean and disinfected tools and implements to avoid transfer of weed seeds in the field.
Mechanical Management:
- Hand weeding using hand tools such as hoes or sickles.
- In case of pre-emergence herbicide application, one hand weeding can be done at 35 DAS after spraying it.
- If herbicide is not sprayed, two hand weeding can be done on 20th and 35th DAS.
(*DAS – Days after sowing)
Weed Management using Herbicides:
Knowing whether a weed is a monocot or dicot can be helpful in identifying it and choosing the most effective method of control. Selective herbicides can be used to target specific weeds while minimizing harm to the surrounding environment and non-target species.
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Pre-Emergence Herbicides:
Spray Pre-emergence herbicide Pendimethalin 30% EC at 1 litre per acre in the wheat field at 0 – 3 days after sowing. Pendimethalin controls both grasses and broadleaved weeds in the wheat ecosystem. Butachlor 50% EC at the rate of 1 litre per acre can also be used for pre-emergence application. It also controls most annual grasses and broad-leaved weeds.
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Post-Emergent Herbicides:
Time of application – After first irrigation at 30 – 35 DAS or 2 – 4 leaf stage of weeds.
| Herbicide Product | Technical content | Dosage | Type of weeds’ it controls |
| Weedmar Super Herbicide | 2,4-D Amine Salt 58% SL | 400 gm/acre | Broad leaved and grassy weeds |
| Sempra Herbicide | Halosulfuron Methyl 75%WG | 36 gm/acre | Grasses |
| Katyayani Vikram Herbicide | Clodinafop Propargyl 15% WP | 160 gm/acre | Grasses |
| Katyayani MSM Herbicide | Metsulfuron Methyl 20% WP | 4-8 gm/acre | Broad leaved and grassy weeds |
| Luficer Herbicide | Piroxofop-propanyl 15% WP | 300-400 gm/acre
|
Grassy weeds |
NOTE:
- The use of herbicides is one of the effective methods for weed management in wheat. But, relying solely on chemical methods of weed management may not be sufficient for effective control of weeds. Following cultural practices, regular hand weeding accompanied with use of herbicides will give effective results.
- Maintain sufficient soil moisture at the time of application of both pre and post emergence herbicides.
- Always remember to rotate the herbicide products with different chemicals to avoid development of resistant weeds.
- Spray post emergence herbicide at 2 – 3 leaf stage of weeds to get favourable results.
- Herbicide sprays should be planned on clear and sunny days only when the leaves are dry. Avoid spraying during high winds or when rain is forecasted.
- Use sticking and spreading agent like Multiplex Nagastha – 180 (0.4 – 0.5 ml/lit of spray solution) for herbicide mix for increased efficiency of the herbicides.
- Do not mix herbicides with pesticides.
- Follow the herbicide label instructions carefully, including recommended rates, application timing, and safety precautions.
