Abstract
The insects, as pollinator, were damaged by high temperature or dryness, and out of them, Scolia tokioenis Betrem was found the most resistant. Meanwhile the shading to lower the temperature and the maintenance of high moisture were both favorable for survival of insects. In practice, therefore, the covering by hemp-cloth was effective to avoid from high temperature. As to pollen castration, it can be conducted by hand easily in September, especially at 9 O'clock as optimum and even at 10 O'clock successfully. But it can be succeeded more efficiently by soaking the mint inflorescence in to 47°C hot water for 5 minutes, and the seeds set by this method germinated normally.
