The control of seed borne diseases of rice seedling by iron-coating seeds in a mass production machine

Abstract

Coating rice seeds with a reduced iron powder is a newly developed method for labor-saving cultivation of rice and direct seeding in flooded paddy fields. Rice seeds inoculated with Burkholderia glumae, B. plantarii, and Gibberella fujikuroi were coated using iron powder of a coarse particle size at a ratio of 0.5 (w/w), which does not conflict with the Japanese law (Fire Service Act). After this, the iron-coated seeds were rusted by spraying them with water and drying. The rusting and drying processes were completed within 2 days by using a mass production machine that was used to iron-coat the rice seeds. When these seeds were sowed in nursery soil directly or after soaking, the 3 diseases caused by the above-mentioned 3 organisms rarely occured, and the protective value ranged from 98 to 100. In addition, “bakanae” disease did not occur after direct sowing in a small container containing flooded paddy soil. Additionally, the disease control effect of using iron-coated seeds was confirmed in practical tests. Because the seed temperature was maintained at less than 36°C in the mass production machine during rusting and drying, the disease control effect was not considered to be because of heat released by the oxidation reaction of iron powder.