Components of female sex pheromone ofEoreuma loftini Dyar

Three chemicals isolated from ovipositor rinses of virgin femaleEoreuma loftini Dyar (Mexican rice borer) moths were identified as (Z)-13-octadecenyl acetate (I), (Z)-11-hexadecenyl acetate (II), and (Z)-13-octadecenal (III) in the approximate ratio 8∶1∶1.3, respectively. Preliminary tests indicate that in laboratory bioassays, these chemicals in the above ratio induce the same activity response as heptane extracts of rice borer ovipositors. Only one combination of two chemicals (I and III, 6.2∶1 ratio) elicited a similar response. Individual chemicals elicited no response. In field tests, the average number of male rice borer moths caught per night over a five-night period was the same in traps baited with 200-600-μg quantities of the 8∶1∶1.3 ratio of chemicals dispensed from strips of filter paper as with traps baited with virgin females. The two-component mixture (I and III, 6.2∶1 ratio) was not active in the field.