Susceptibility to DDT, malathion, fenitrothion and dieldrin of three flea species in the boyolali plague endemic area, Central Java, Indonesia.

Insecticide susceptibility tests with 4% DDT, 0.5% and 5.0% malathion, 1% fenitrothion, and 0.2% dieldrin impregnated papers were carried out with fleas spp. from the Boyolali plague zone. The field flea (Stivalius cognatus) which was highly susceptible to malathion before, has now been found to be resistant to the insecticide, but was found susceptible to the other three insecticides. The oriental rat flea (X. cheopis) which found previously highly resistant to DDT, was now found to be less resistant, and susceptible to other insecticides tested. From preliminary tests with DDT to another field flea (Neopsylla sondiacus), it was found to be susceptible to the insecticide.