In a recorded interview with journalist Ray Snoddy at the IBC technology conference, Grade told the audience in Amsterdam that he did not consider the rise of internet giants such as Google, which owns YouTube, to be a threat to ITV.
Grade said: "The day that Google or Joost or any of these people start investing £1bn a year in UK content is the day I'll start to be worried.
"They're all parasites, they just live off our content is what they do. As long as we can create the content, the content is the keys to the castle for us going forward."
The ITV boss's attack on YouTube comes as the website, which expects to make $200m in ad revenues this year, defends itself against a $1bn content infringement lawsuit brought by US TV company Viacom.
Grade, who recently put back ITV's target of reaching £150m in online revenues by two years to 2012, said mobile TV was not a top priority: "Mobile will have to wait. It's clunky, it's slow and 3G streaming seems usually not to work."
Grade, who has been under pressure as ITV's share price has fallen sharply and rumours of a potential takeover by Mediaset or Big Brother producer Endemol have emerged, also argued that the group can weather the downturn.
"Whether we can survive as an independent company is a matter for our shareholders. They will decide in the end on such questions."
"Do I believe that this business has a long term future? Absolutely I believe that. I believe that because of our content skills."
Grade's comments come just a week after ITV hired Jason Binks as its new digital director.
Binks, who was previously a sales director at Roo, is in charge of striking distribution agreements with companies such as iTunes and Amazon.