Abstract
As has been reported in the preceding paper, different varieties of tea plants are infested by the tea red spider mite, Tetranychus kanzawai KISHIDA, in a very different measure; the varieties Asatuyu, Benihomare, Tamamidori, U-4 and Y-1 are susceptible to the infestation by the mite, while Y-3, Y-5 and Z-1 are resistant. In order to make clear the causes of the varietal differences, some indoor experiments on food-plant selection were undertaken. The mite has an ability to elect tea leaves as a food, in turn, leaves of the susceptible varieties are preferable to resistant variety leaves. The mite also prefers young leaves to mature leaves within a variety. These finding are in good agreement with the results from the field observations. Among two phases of insect behaviour by which food-plant selection is brought about, the first phase (food finding behaviour) seems to be less important for the food-plant selection of this mite, because the mites attain initially on both susceptible and resistant variety leaves of tea in equal numbers when they are allowed to choose tea leaves. It is considered, therefore, that the second phase of the food-plant selection, food acceptance, is responsible for determining the food-plant selection of the mite, and, consequently the mite infestation of tea plants.
