抄録
In the spring of 2001, more than half of the soybean seedlings sown on a small field (approximately 1.9 are) in Kunneppu, Hokkaido were infested by Hokkaido hare, Lepus timidus ainu. Most of the infestations occurred before late June, and unifoliate primary leaves were cut off just above the cotyledons. The infestation rate was highest on the marginal row of the beans and tended to decrease in the inner rows of the field. In each row, infested plants tended to occur in batches, rather than in a random sequence. In autumn, the infested plants had smaller numbers of branches, lower plant heights, and smaller numbers of pods than those of the non-damaged plants and account for about 11% loss in yield. The estimated yield loss of the soybean field caused by the hare, calculated using “ratio of infested plants ×11%”, might be negligible when the proportion of infested plants is small.
