define pesticides and weedicides? Share with your friends Share 0 Nikhil Vijay answered this Pesticides are chemical sprayed on plants to prevent them fro insects and pests. Weedicides are chemicals sprayed on weeds to kill them. 0 View Full Answer Sneha Varsha answered this Pesticides these are chemical sprayed on plants to prevent them from pests. Weedicides these are chemicals sprayed on weeds to kill it 0 Vineet Arora answered this to kill pest its pesticides and to kill weeds its weedicides 0