It has been reported that entomopathogenic nematodes can be used as biological control agent to manage species of the American (Periplaneta americana) and the German (Blattella germanica) cockroaches. Read following paper for more information
Maketon, M., Hominchan, A. and Hotaka, D. 2010. Control of American cockroach (Periplaneta americana) and German cockroach (Blattella germanica) by entomopathogenic nematodes. Revista Colombiana de Entomologia 36: 249-253.