Mr Etheridge took aim at Nicola Sturgeon in his response to the comments.
He told Express.co.uk: "I am well aware there are other similar sized countries that have thrived but they didn't have Nicola Sturgeon and Jean-Claude Juncker at the helm.
"A country of any size can thrive if it has the right economic policies based on free markets and deregulation rather than taking money away from hard working people and wasting it on foreign aid, quangos and trade policies which push... up prices.
"As for saying the UK economy is bad, the UK economy has defied Project Fear and I believe if we have the right blend of free trade, deregulation and lower taxes, everyone in this country can be better off."
The Brexit campaigner also responded to Mr Wilson’s calls for “mutually beneficial” trading with the UK and the EU.
He said it appeared to indicate the SNP did not grasp "the huge benefits of free trade which politicians get in the way of".
Mr Etheridge added: ”Free trade makes the world better off, through a better allocation of scarce resources to greater competition, helping the developing world and ending the control that huge multinationals and cartels have over government policy."