Chemical seed treatment for the control of seedling disease of water-sown rice

The most effective fungicide formulations, rates, and method of application for reducing seed rot and seedling disease of water-sown rice were determined in greenhouse and field studies. The efficacy of over 30 chemical formulations that had shown biological activity against Achlya klebsiana and Pythium sp. in laboratory and greenhouse trials were tested. Difolatan® and captan treatments have consistently been the most effective in improving total stand establishment. Treatment by either slurry or spray mist with flowable formulations and allowing the fungicide to dry on the seed prior to the soaking process proved to be more effective in preventing seed rot and seedling disease than application made after soaking or by adding the chemicals to the soak water. Seed treated prior to soaking showed no detrimental effects from the chemicals after storage up to four months. Analysis of chemically treated seed before and after soaking and of the soak water revealed that substantial portions of the fungicide were lost during the soaking process. The benefits from fungicide seed treatment in water-sown rice are most obvious during the early planting season, when environmental conditions are often unfavorable for germination and seedling growth.