Abstract
Submerged application of IBP (O, O-diisopropyl-S-benzylthiophosphate) granules in irrigation water, 3-6Kg per 10 ares, showed that the culm length of rice plants became shortened, the lower internodes growing shorter than those of the control plants.
IBP gave more shortening effect against the culm length in application 6 kg than 3 kg per 10 ares, and the most from the most active-tillering stage to the young panicle formation stage. The load of culm base at breaking-point was also apt to be increased owing to shortening of culm length.
It was observed in field.s that the greater the degree of shortening of culm length, the less the degree of lodging. IBP application showed the increasing of the number of cilicified cells in a leaf blade of the rice plants.
On the one hand, IBP was the most effective for control of neck rot, in application 6 Kg per 10 ares, 10 days before heading (88% disease control) and still effective at the maximum tiller number stage (81% disease control).
From these results, it seems that submerged application of IBP in irrigation water, 6 Kg per 10 ares, at the maximum tiller number stage can be practically used for both prevention of lodging and control of neck rot of rice plants.
