In general,they warned against the evils of both practices and some compared it to how Communism is basically satan's plan in heaven on earth. Communism would have everyone forced to work together communally, Christ's plan is to allow everyone to CHOOSE to work together, not be forced to do so and therefore have no agency. Several have warned that America was on it's way to such a path of socialism under "secret combinations" like those warned about by Book of Mormon prophets. For some specific quotes, click on the link below:
http://www.latterdayconservative.com/quotes-about/communism/
Here are some conference talks from LDS.org and ldsinfobase.net you might be interested in. Ezra Taft Benson is most famous for giving talks against socialism/communism. These warnings actually can be traced al the way back to George Albert Smith and earlier, so even since the begginings of the 1900's prophets have warned against communism. The warnings continued through the 1980's, but have generally not been in talks after the 1980's. Though Thomas S Monson has warned against "political machinations"
Marion G Romney(who is actually 2nd cousin to Mitt Romney)
http://www.ldsinfobase.net/liberty/MGR_66apr.html (1966 april general conference)
Ezra Taft Benson:
http://www.ldsinfobase.net/liberty/ETB_60apr.html (1960 april general conference)
http://www.ldsinfobase.net/liberty/ETB_61oct.html (1961 october general conference)
http://www.ldsinfobase.net/liberty/ETB_62apr.html (1962 april general conference)
http://www.ldsinfobase.net/liberty/ETB_63apr.html (1963 apr gen conf)
http://www.ldsinfobase.net/liberty/ETB_65apr.html (1965 apr gen conf)
http://www.ldsinfobase.net/liberty/ETB_66oct.html (1966 oct gen conf)
http://www.ldsinfobase.net/liberty/ETB_69oct.html (1969 oct gen conf)
https://www.lds.org/general-conference/1979/10/a-witness-and-a-warning?lang=eng (1979 oct gen conf)
I also suggest going to ldsinfobase.net/liberty and going to the "our awful situation" link. It provides many quotes warning and suggestive of a secret combination seeking to destroy America and fundamentally transform it.