Disruption ofMalacosoma disstria(Hübner) male moth orientation to female-baited traps by chemical permeation of the air in small field plots has been demonstrated: (5Z,7E)-5,7-dodecadienal, (5Z,7Z)-5,7-dodecadienal, and (Z)-7-dodecenal individually were effective. (5E,7E)-5,7-dodecadienal did not disrupt. An isomeric mixture of 5,7-dodecadienals, such as might be the crude product of Wittig-type synthesis, also disrupted effectively.