Seasonal Abundance of Indian-meal Moth Plodia interpunctella Hübner (Lepidoptera)

Abstract

The Indian-meal moth, Plodia interpunctella Hübn. is the most serious pest of confectionery in Japan. The seasonal population trend of the pest was examined in a Japanese mosquito net put up at the laboratory of Miyazaki University using rice-bran as a food of the insect. The numbers of alive moth, emerged and dead one were recorded everyday. The fluctuations of room temperature and moisture were recorded, too.
In southern Kyushu, from late of March the moth of the first generation may begin to emerge and reach a peak of abundance at the end of April. From early to middle of June the moth of the second, from middle to late of July the third, and from early to late of August the fourth generation appear. At the first half of October the moth of the fifth generation emerge and almost all diapause may occur at the full grown larvae of this generation. The ‘developmental zero’ and the ‘thermal constant’ of this species were estimated at the temperature of 11.5°C and 462.5 in degree-days.