Chemical Pesticides? Can they be used on Veggie Plants?

[ooHa!]

Everyone is talking about organic pesticides for 'edible' gardens.  I have
tried coffee grounds to diatomaceous earth dusting.  There numerous bugs and
flying things, ants eating the leaves of my plants like crazy.  I would like
to get your opinions on using the 2% diazonon  or other pest control
chemicals sold in the market. Please share your thoughts. Many thanks.
Rama