Potential of cypermethrin or diazinon and their combined action with piperonyl butoxide (PBO) against Periplaneta americana L

Cockroaches are high priority urban pests because their aesthetically unappealing damage stored products and household goods and transmit diseases. (Ebeling, 1978). It becomes a public health problem due to their association with human waste and disease and their ability to move from sewers into homes and commercial establishment. They are well known pest of considerable economic and medical importance (Cameron, 1956). Cockroaches also a mechanical vector of several communicable diseases like gastroenteritis and food poisoning (Bitter, 1949; Eades et al, 1954) transmit Bacillus staphylococci poliomyelitis viruses and destructive mould (Sylverton et al., 1952; Morrel, 1991). There are almost 4,00 species of cockroaches (Service, 1980) . Among them American cockroach, Periplaneta americana L. is an obnoxious, omnivorous and filthy domestic pest of tropical zone