AGR 3102 Principles of Weed Science Unit 5: Methods of Weed Control Integrated Weed Management (IWM)

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AGR 3102Principles of Weed ScienceUnit
5Methods of Weed ControlIntegrated Weed
Management (IWM)

• Muhammad Saiful Ahmad Hamdani

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Methods of Weed Control
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Integrated Weed Management (IWM)

• Definition combination of multiple management
  methods to reduce weed population to an
  acceptable level while preserving the quality of
  existing habitat, water, and other natural
  resources.
• Involves 2 critical elements
• - using multiple control tactics (cultural,
  mechanical,
• biological, and chemical control methods).
• - integrating a knowledge of weed biology and
• ecology into the management system.

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IWM - Rice
Critical period of  weed control 20-60 DAS
Cultural method Healthy and highly competitive variety Flooding 3) High density
Mechanical method Land preparation (ploughing) Hand weeding Rotary weeder
Chemical method Apply pendimethalin 1.0kg/ha on 5 DAS or Pretilachlor safener (Sofit) 0.45kg/ha on the day of receipt of soaking rain, and apply Nominee (bispyribac-sodium) 0.35kg/ha at 7-15 DAS)
Biological method Release Tilapia spp. to control aquatic and floating weeds such as Azolla and Salvinia
Remarks Can also include preventive method 1) Certified seeds 2) Clean planting and tilling machines
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IWM - Maize
Critical period of weed control 3 to 6 weeks after germinating
Cultural method
Mechanical method One hand weeding on 40-45 days after sowing
Chemical method Pre-emergence application of Atrazine (1-2 kg ai/ha) Combined application of Alachlor (2 kg/ha) and atrazine (1kg/ha) is more effective and have wider spectrum of control
Biological method  
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IWM - Sugarcane
Critical period of  weed control 4 to 5 months after planting
Cultural method High density planting
Mechanical method Remove the weeds along the furrows with hand hoe. along the ridges on 25, 55 and 85 days after planting for removal of weeds and proper stirring
Chemical method 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 To obtain best results, sequential application of preemergence and post emergence herbicides like Glyphosate (0.8 to 1.6 kg/ha) Paraquat (0.4 to 0.8 kg/ha).
Biological method  
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Advantages of IWM

• Can develop a long-term weed management plan,
  that considers all available management control
  techniques to control weeds.
• Likely to hinder the adaptation of weeds to any
  single control tactic, i.e. chemical
  control-herbicide resistance.
• IWM takes a common-sense approach to weed control
  (helps reduce hazards to people, animals and the
  environment).
• IWM works well for agricultural, home, garden and
  workplace environments.

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Advantages of IWM cont

• Avoid unknown problems in the future i.e. some
  biological agent may become invasive spp., insect
  may mutate and change their diet attack other
  crops and plants mechanical will reduce soil
  nourishment and cause erosion water scarcity is
  a major issue nowadays.
• Consists of a series of evaluations, decisions,
  and control practices which focus on economical
  and effective control of weed with consideration
  of ecological conservation.
• Most important, IWM helps decrease herbicide use.

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• Principle of IWM
• THE RIGHT COMBINATION OF DIFFERENT WEED CONTROL
  METHODS FOR THE RIGHT CROP ENVIRONMENT AT THE
  RIGHT TIME

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Future weed control - the super IWM???