Inhibition of Non-parasitic Damping-off ("Murenae") of Young Rice Seedlings in Nursery Boxes I. Effect of 3-hydroxy-5-methylisoxazole on damping-off and the growth of rice seedlings

摘要

This investigation was conducted to determine the effectiveness of 3-hydroxy-5-methylisoxazole application on the inhibition of non-prasitic damping-off or "Murenae" in young rice seedlings grown in nursery boxes. The results are summarized as follows: 1. Application of 3-hydroxy-5-methylisoxazole before seeding was highly effective in reducing the incidence of damping-off. The compound was very effective when applied ei her as a dust or granule by soil incorporation or as a liquid soil injection methods. 2. The growth of shoots and roots of rice seedlings in treated nursery boxes was inhibited temporarily soon after germination, but growth recovered in a short time. The dry weight or rice seedlings 20 days after seeding was greater in the treated nursery boxes than in the control. 3. The compound increased the rooting ability and growth of root hairs. Consequently, the increase in the number of tillers in rice seedlings occurred much sooner after transplanting as a result of the chemical treatment. 4. It was also observed that both guttation and drought resistance were increased by the chemical treatment. These results indicate that 3-hydroxy-5-methylisoxazole reduces the incidence of non-parasitic damping-off or "Murenae" and damping-off caused by Fusarium sp. and Pythium sp. in rice seedlings. The reduction in both types of damping-off appears to be due to the increased growth activity of roots.