Upvote:5
Would it be possible to enter Greece with Italy Schengen visa?
A Schengen visa is valid for the whole Schengen area.
However, you are required to apply to the country which can be considered your primary destination. Or if you stay for an equal amount of time in more than one country, then the country whos border you will cross first.
See: https://eeas.europa.eu/sites/eeas/files/frequently_asked_questions_en.pdf
As your purpose is to attend a conference in Greece and you have no business or personal need to travel to Italy at all then the Italian authorities would reject your application.