- 1) Integrated Weed Management (IWM) involves employment of different methods of weed prevention and control in right proportion and at appropriate time against the target weeds with minimum damage to the environment.
- 2) It is the suitable combination of preventive measures, mechanical, cultural, biological and chemical methods of weed control for minimizing the weed growth and population and maintain them below the level of economic injury to the crop with minimum damage to the environment or minimum environmental pollution.
Importance of Integrated Weed Management:
- Weed can be controlled by adopting different methods however, each weed control methods has advantages and disadvantages or limitations. The continuous use of the same method leads to build up of tolerant weeds.
- Therefore, the suitable combination of different methods of weed control or integrated weed management (System Approach) should be practiced for minimizing the losses caused by weeds in different crops and also for protection of the environment.
Integrated weed management
1. Rice
| Critical period of weed control | 20-30 DAT |
| Cultural method | 1) Hand weeding 2) Hand pulling 3) Pudding 4) Flooding |
| Mechanical method | 1) Weeder (Float) 2.Conoweeder/Rotary weeder |
| Chemical method | Apply pendimethalin 1.0kg/ha on 5 days after sowing or Pretilachlor + safener (Sofit) 0.45kg/ha on the day of receipt of soaking rain followed by one hand weeding on 30 to 35 days after sowing. |
| Biological method | 1. Hirsch – Manniella spinicaudata is a rice root nematode which controls most upland rice weeds 2. Azolla |
| Remarks | I. Substitution and preventive method: a) Stale seed bed technology b) Land preparation c) Water management |
2. WHEAT
| Critical period of weed control | 15 – 30 DAS |
| Cultural method | a) Hand Hoeing b) Inter cultivation c) Criss-cross sowing |
| Chemical method | 1. 2, 4D (1 – 1.5 kg ai/ha) 2. Mixture of Isoproturan (0.75 kg ai/ha) and 2, 4D (0.4 kg ai/ha) during 30- 35 DAS |
| Remarks | II. Complimentary weed control methods a) Cultivars b) Seedling age /planting method c) Fertilizer management d) Cropping system |
3. SORGHUM
| Critical period of weed control | 21 – 42 DAS |
| Cultural method | 1.Hoe and hand weed on the 10th day of transplanting if herbicides are not used.2.Hoe and weed between 30 – 35 days after transplanting and between 35 – 40 days for a direct sown crop |
| Chemical method | 1.Apply the pre-emergence herbicide Atrazine 50 WP – 500 g/ha on 3 days after sowing as spray on the soil surface2.If pulse crop is to be raised as an inter-crop in sorghum do not use Atrazine. |
| Remarks | 1. Inclusion of cotton crop in the rotation |
4. MAIZE
| Critical period of weed control | Maize 2 to 6 Weeks |
| Cultural method | One hand weeding on 40-45 days after sowing |
| Chemical method | 1. Pre-emergence application of Atrazine (1-2 kg ai/ha) 2. Combined application of Alachlor (2 kg/ha) and atrazine (1kg/ha) is more effective and have wider spectrum of control |
5. GROUNDNUT
| Critical period of weed control | Upto 45 days |
| Cultural method | After 35 – 40 days one hand weeding may be given. |
| Chemical method | 1. Alachlor (1-5 kg/ha) – pre emergence application |
6. SUNFLOWER
| Critical period of weed control | 4-6 weeks |
| Cultural method | Hoe and hand weed on the 15th and 30th day of sowing and remove the weeds. Allow the weeds to dry for 2 – 3 days in the case of irrigated and then give irrigation. |
| Chemical method | 1. Apply Fluchloralin at 2.0 l/ha before sowing and incorporate or apply as pre-emergence spray on 5 day after sowing followed by irrigation or apply Pendimethalin as pre-emergence spray 3 days after sowing. |
7. COTTON
| Critical period of weed control | First 45 days |
| Cultural method | 1.One hand weeding on 45 DAS will keep weed free environment upto 60 DAS2.Hoe and hand weed between 18th to 20th day of sowing, if herbicide is not applied at the time of sowing |
| Chemical method | 1. Diuron (0.5 – 1.5 kg/ha), Monuron (1-1.5 kg/ha), Fluchloralin (1-1.5 kg/ha) applied as preemergence/ preplanting |
8. PULSES
| Critical period of weed control | First 30-35 days |
| Cultural method | 1.One hand weeding on 30 days after sowing gives weed free environment throughout the crop period2.If herbicides are not applied give two hand weedings on 15 and 30 days after sowing. |
| Chemical method | 1. Fluchloralin (1-1.5 kg/ha ), Pendimethalin (0.5-1.0 kg/ha) as Pre emergence (preplanting incorporation) |
9. TOBACCO
| Critical period of weed control | First 9 weeks |
| Chemical method | 1. Fluchloralin (2-3 kg/ha), Pendemethalin (1-1.5 kg/ha) as pre-emergence application |
10. SUGARCANE
| Critical period of weed control | 4 to 5 months |
| Cultural method | Remove the weeds along the furrows with hand hoe. |
| Mechanical method | If herbicide is not applied work the junior-hoe along the ridges on 25, 55 and 85 days after planting for removal of weeds and proper stirring |
| Chemical method | 1. Pre-emergence herbicides like atrazine (2 to 3 kg/ha) Simazine (2 to 3 kg/ha), Alachlor (1.3 to 2.5 kg/ha) etc., will generally last for 8 to 12 weeks 2. To obtain best results sequential application of Preemergence and post-emergence herbicides or post emergence herbicides like Glyphosate (0.8 to 1.6 kg/ha) Paraquat (0.4 to 0.8 kg/ha). |