Discuss various methods of weed control.

Mechanical Methods:

1. Removal of weeds by pulling them out with hand.

2. Removal of weeds by using trowel (khurpa).

3. Removal of weeds by ploughing, burning and flooding before sowing.

4. Removal of weeds by interculture.

Cultural Methods :

1. Timely sowing of crops.

2. Proper seed bed preparation

3. Intercropping

4. Crop rotation

Chemical Methods:

Destroying the weeds by spraying special chemicals called weedicides like, $2,4-D(2,4$-dichlorophenoxy acetic acid), Butachlor, Atrazine, isoproturon, etc.

Biological Methods:

In the biological control of weeds, some appropriate insects or some other organisms are deliberately put into the crop field having weeds. The insects or other organisms selectively destroy the weed plants but do not harm the crop plants. For example, Cochineal insects are used to eradicate the weed called Opuntia. Mexican Beetle and Cassia can check the growth of Parthenium. Aquatic weeds are controlled by the fish called grass carp.