Natural Pesticides and manures

Can natural Pesticides be derived from fruits like lemon, orange skins, lemon grass, அரளி விதை, சாத்துக்குடி or mosambi, mixed neem extracts oil, Seeds, leaves, juices, கள்ளி பால், Other natural acidic forms. And very strong bitter leaves, that could kill the pests instantly when sprayed or given as feeds in various forms (liquids, solids, Air, semi-liquid.... So on..)?

Similarly, manures could be prepared in different forms.