Studies on the distribution and abundance of the lima bean pod borer, Etiella zinckenella Treitschke, and the soy bean pod borer, Grapholitha glycinivorella Matsumura : IV. On the distribution of the two species in the world and their host plants

In the previous paper I discussed the geographical distribution of the two species, Etiella zinckenella Treitschke and Grapholitha glycinivorella Matsumura in Japan. The northern limit of distribution of E. zinckenella is indicated by an annual mean temperature of 11.5-12.5℃ and a mean temperature of warmer season (from May to October 18.5-19.5℃, ) and pointed out that the latter will be more applicable in north China. On the other hand I mentioned that G. glycinivorella is found throughout Japan, but not found in any island far south of Kyushu, therefore it may be sayed that the southern limit of distribution of the species exists between Kyushu and Tanegashima Islands. In the present paper I made a further investigation of the geographical distribution of the two species throughout the world. Investigation was made based on the reliable reports on the species. The results obtained are summarized as follows. E. zinckenella widely distributes in the world, i.e. Asia, Europe, Africa, North America, Central and South America, and Australia. It is generally found in the tropical, subtropical, and warmer regions of the temperate zone but not found in frigid, subfrigid, and cooler regions of the temperate zone. The northern limit of distribution of E. zinckenella exists in the southern district of Europe, north China, Honshu of Japan, northern district of America, and the indicator of the northern limit is roughly suggested by the mean temperature of the warmer season (from May to October, about 19℃ (17-20℃)). Therefore, if it is considered with some width to the mean temperature of the warmer season 18.5-19.5℃ which I suggested as an indicator of the insect in Japan, it will be able to applicate as an indicator of the northern limit in the world. The host plants of E. zinckenella are distributed in 21 genera and 30 species of leguminous plants. But there is considerable local differences, for instance, the host plants are generally abunda nt in the tropical, subtropical regions but a few in the colder regions ; and soy bean is one of the commonest hosts in Asia and Europe, but is not infested by the insect in North America, pseudo-acacia is commonly infested by the insect in Europe but is not reported from Asia, North America, and etc. It seems to be attributed to the fact that the leguminous plant flora not only regionally differs but the suitability of the species for the host plants also differs. G. glycinivorella is a peculiar species in the Far East. The species distributes in the southern Sikote Alin of Siberia, Manchuria, north China, Korea, Hokkaido, Honshu, Shikoku, and Kyushu, and is abundant in the central or south Manchuria, Tsingtao of China, Hokkaido, Tohoku, Hokuriku, Kanto, Sanin districts of Japan where the mean temperature of warmer season is between 16-21℃. It appears that the southern limit of the species exists surrounding far south of Kyushu and northern central China. These limits may be roughly coincide with the mean temperature of the warmer season about 23-24℃. The host plants of the species are found in 3 genera and 4 species of leguminous plants, soy bean being the commonest one. Both species occur in the same region of the mean temperature of warmer season 19-24℃ in the Far East. Especially the damage of the cropes caused by the two species is great in the region of about 20-22℃.