Question

what are wedicides give two examples of wedicides

Answer 1

Weeds are unwanted plants growing among wanted crops and compete with crop plants for sunlight, nutrients, water etc. 
Weedicides are the chemicals which are sprayed over field to get rid of weeds. They will not show any effect on crop plants. Two popularly used weedicides are   2,4-D Ethyl ester, Neem extract, Glyphosate etc.

Answer 2

Weedicides are the substances which are used for removing weeds ( unwanted plants).

Ex - Dichlorophenoxy acetic acid.
Naphathelene acetic acid.