Abstract
Effects of five synergists, namely, piperonyl butoxide, S-421, Safroxan, MGK 264 and n-propyl-isom, as used in combination with pyrethrins and allethrin, were evaluated comparatively in tests with house flies, Musca domestica, employing the spray chamber method, the Petri-dish contact method and the topical treatment method. In the synergism to pyrethrins evaluated in terms of (LD)_<50> or (KT)_<50> for each synergized formulation used in the test, the five synergists are ranked as follows in order of superiority for the respective methods indicated : Topical Application : piperonyl butoxide, n-propyl-isom, Safroxan, MGK 264, S-421 Spray Chamber : piperonyl butoxide, n-propylisom, MGK-264, S-421, Safroxan Petri-dish Contact : piperonyl butoxide, MGK-264, n-propyl-isom, Safroxan, S-421 In the synergism to allethrin evaluated on the same basis as above, the five are ranked in superioirty as follows : Topical Application : S-421, Safroxan, n-propylisom, piperonyl butoxide, MGK-264 Spray Chamber : S-421, piperonyl butoxide, Safroxan, MGK-264 Petri-dish Contact : MGK-264, piperonyl butoxide, S-421, Safroxan, n-propyl-isom As used with each principal toxicant, the order of superiority among the five synergists varied with the test method employed. Regardless of the method employed, however, the synergistic effect of piperonyl butoxide on pyrethrins and that of S-421 on allethrin were indisputably high.
