Pheromone-based auto-confusion for mating disruption of Plodia interpunctella (Lepidoptera: Pyralidae) in structures with raw and processed grain products

Abstract

Experiments are reported using an auto-confusion formulation of a sex pheromone for mating disruption of the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae). A seed warehouse and a pet food store were selected for mating disruption (MD) treatment using an auto-confusion formulation named Exosex® SP Tab dispensers, while a pilot feed and a pilot flour mill were used as untreated controls. In the two buildings selected for mating disruption, the occurrence of P. interpunctella males after the application of MD was significantly reduced, as compared with the occurrence of this species before MD. The number of moths captured in all treated facilities ranged between 20 and 25 moths/trap on the first and second week of the trial respectively, while those number of moths captured on the traps in the seed warehouse decreased to an average of 5.1 moths/trap on the third week after MD dispensers were deployed. After the start of mating disruption on week 3, the number of moths captured gradually increased in the seed warehouse between May and July and peaked at week 10. The highest number of moths was recorded from early September to early October in the pet food store. All the parameters including the facilities, trap locations and weeks differed significantly in the mating disruption trials. The patterns of population fluctuation indicated that moth captures were reduced when the MD was applied in the 3rd week in all the facilities and remained constant throughout the trials with a few exceptions. There were no significant differences in larval numbers in oviposition traps between the treated and the untreated areas, with the exception of the seed warehouse for which fewer larvae were found in the treated time. The present study illustrates potential for mating disruption via auto-confusion system in reducing the population densities of P. interpunctella.