Climate and Potential Range of Distribution of Stored-Product Mites in Japan1

Abstract

The relationship between the mean monthly normal temperatures at 116 locations representing all parts of Japan and the minimum temperature threshold for breeding was determined theoretically for major species of stored-product mites. The monthly mean temperature of 10 or higher in unheated storages was considered minimum for the development and reproduction of the mites. From these relationships the number of months when such storages would have temperatures suitable for the breeding of mites was calculated for various regions of Japan. Thus Japan was divided into 4 zones in which the temperature was above 10°C for 9-12, 7-8, 5-6, and 4 months. Although most regions of the country were considered to be vulnerable to infestation by some species of mites, Kanto, parts of Chubu, Kinki, Chugaku, Shikoku, Kyushu, Okinawa district, and other islands in south Japan where the mean monthly temperature exceeds 10°C for 7-12 months were predicted to be most suitable for the breeding of storage mites. The most important storage mite in Japan, the mushroom mite, Tyraphagus putrescentiae (Schrank), is likely to infest granaries and warehouses throughout Japan except Hokkaido. Glycyphagus destructor (Schrank) is predicted to be common in Kinki district and the Seto Inland Sea area although it could infest grain and food in Hokkaido and Honshu. Cheyletus spp. are likely to have a distribution similar to that of T. putrescentiae and G. destructor. The species requiring extremely high moisture, such as Caloglyphus bertesei (Michael), Lardoglyphus konoi (Sasha & Alabama), and Aleuroglyphus ovatus (Troupeau) are expected to thrive in the hot and humid southern half of Kyushu, southern coastal areas of Shikoku and Kinki districts, and Okinawa, where the mean monthly temperatures remain above 10°C for 9-12 months. The ranges of distribution have been estimated for other major mite pests of stored products.