Seasonal prevalence of pink scavenger caterpillar, Anatrachyntis rileyi (Walsingham) (Lepidoptera : Cosmopterigidae) in rice and feed mills.

Occurrence of pink scavenger caterpillar, Anatrachyntis rileyi (Walsingham) , which was not known to be established in Japan, was investigated in eight rice mill facilities, two feed factories and one rice processing facility for Awamori brewing in Ibaraki, Kagoshima and Okinawa, Japan. Seasonal occu rrence of the moth was investigated with two kinds of sticky trap, a ribbon trap suspended from the ceiling and a floor mounted trap, at ten different sites in a large scale rice mill, in Tsuchiura, Ibaraki from June 1996 to June 1997. Moths were caught at all sites, and were captured every week exc ept during the winter. The moths emerged from old rice bran in the rice mil ls and the feed factories investigated in Ibaraki and Kagoshima and an adul t was also captured in Okinawa, indicating that A. rileyi has already widel y colonized Japan. On the basis of the total effective temperature for A. r ileyi, this species is estimated to have six generations per year in Tsuchi ura. The number of adults captured by the ribbon traps was better correlate d to the temperature in the mill than that of the floor mounted traps. Howe ver, seasonal changes in the number of adults captured by the floor mounted traps corresponded better to the times of adult emergence in the year esti mated by the total effective temperature (degree-day).