Methods of Weed Control
A. Cultural Methods
Cultural methods, alone cannot control weeds, but help in reducing weed population. These should, therefore, be used in combination with other methods. Common cultural practices that help in controlling weeds are
- Field Preparation – field to be kept weed free
- Fertilizer Application
- Irrigation and Drainage
- Selection of crop variety
- Crop rotation – growing more than one variety of crop in the same year
- Mulches – a protective covering on soil surface that inhibit top growth of weeds
- Planting Density – optimum plant population prevent weed infestation
- Cleanliness of the farm.
B. Physical Methods
In physical method, either manual or mechanical power is used to pull out weeds. Depending on weed and crop situation one or combination of these methods are used:
- Hand weeding – pulling out of weeds with hands
- Hand hoeing
- Digging – removes underground parts of weeds
- Mowing – a machine operated practice
- Cutting
- Dredging and Chaining
- Burning and Flaming
C. Biological Methods
Utilization of natural living organism, such as insects herbivorous fish, other animals, disease organisms and competitive plants to limit their growth. In biological control method, it is not possible to eradicate weeds but weed population can be reduced. This method cannot be used to control all types of weeds.
Following six kinds of Bio-agents were used to control weeds:
- Insects: Prickly-pear weed (Opuntia) was controlled in India by Dactylopius tomentosus, a scale insect.
- Carp fish: Common carp and Chinese carp control aquatic weeds.
- Fungi: Water hyacinth can be controlled by Rhizoctinia blight.
- Snails: Marisa spp and other fresh water snails feed on submerged weeds like coontail and algae.
- Mites : A spider mite (Tetranychus spp) is found to be useful in controlling prickly pear.
- Competitive plants
D. Chemical Methods
Use of chemicals generally referred as herbicides which are capable of killing or inhibiting the growth of plants.