Abstract
The relationship between the mean monthly normal temperatures at 116 geographical locations in Japan and the minimum temperatures below which development ceases was established theoretically for major species of stored product insects. In unheated premises monthly mean temperatures of 17°C or higher were considered minimum for the development o most injurious stored product insects including Callosobruchus chinensis, Sitophilus spp., Cadra cautella, and Plodia interpunctella, 20°C or higher for Tribolium spp., Oryzaephilus surinamensis, and 24°C or higher for Trogoderma granarium, Rhizopertha dominica, and Cryptolestes ferrugineus. From these relationships the number of months when storage premises have conditions favorable for the development of certain species or groups of species were calculated for various areas in Japan. Maps based on these evaluations show that Sitophilus and most other stored product insects can cause serious problems throughout Japan except in the central and northern part of Hokkaido. Rhizopertha dominica can attack stored food in Sikoku, Kyushu and the soluthern coastal areas of south-west Honsyu. But the severity of its infestation is likely to be minimised due to competition from Sitophilus spp. Triborium spp. and O. surinamensis are likely to occur in all parts of Japan except Hokkaido and most of north central Honsyu. Trogoderma granarium, because of its need for hot and dry conditions and pressure of inter-specific competition from Sitophilus spp. and R. dominica, was thought unlikely to be a serious pest of stored grain in most areas of Japan except in large warehouses along the coast of Seto Inland Sea, especially around Kobe and Kure.
