Abstract
The pattern of cross resistance and the synergistic action of piperonyl butoxide (PB) and triphenyl phosphate (TPP) with phenthoate on the resistant (OSS-R and OKR-R) and susceptible (OSS and OKR) strains of the diamondback moth were investigated. The resistant strains showed high level of cross resistance to methomyl. The OKR-R strain showed high cross resistance to prothiophos and cyanophos, and showed lowe cross resistance to dichlorvos and cartap. The OSS-R strain showed low cross resistance to all four insecticides. Neither resistant strain exhibited cross resistance to acephte and fenvalerate. No synergistic action of PB with phenthoate against the diamondback moth was observed. However, there was high synergistic action of TPP with phenthoate (both in pre- and simultaneous-treatments).
