Compare sub strings in a List of strings

Question

I have declared following List of strings-

List<string> lstfruits= new List<string>(){

{ "apple-2015.05.18.html" },

{ "apple-1997.01.11.html" },

{ "mango-2013.02.12.html" },

{ "peach-2015.04.12.html" },

{ "peach-1998.11.12.html" },

{ "other-2013.02.12.html" },

};

I need to match all records which contain 'apple'. Below are the results that I want-

"apple-2015.05.18.html"

"apple-1997.01.11.html"

I wrote below , but it returns zero results-

var items = lstfruits.Where(pp => pp.Substring(0, pp.IndexOf('-')) == "apple");

Please help where I am wrong.