Control of seed borne diseases of rice seedlings by coating seeds with iron

Abstract

Iron coating of rice seeds was originally developed as a seed preparation for direct sowing in flooded paddy fields to reduce the number of floating seedlings and injuries from birds. Here we examined the efficacy of iron coating of rice seeds in the control seed borne bacterial and fungus diseases, because metal ions (e.g., copper and silver) have antimicrobial activity and have been used as a seed disinfectant. When rice seeds inoculated with Burkholderia plantarii, B. glumae or Acidovorax avenae subsp. avenae were coated with iron powder just before seeding, the subsequent seedlings had not developed any disease symptoms by two weeks after seeding. Iron coating was also effective against “Bakanae” disease, brown spot and blast caused by fungi. Four kinds of iron powders were tested, and all were effective against bacterial seedling blight, bacterial grain rot and bacterial brown stripe. Iron coating of rice seeds is advantageous because it can be used for both direct sowing in paddy fields and raising seedlings in nursery boxes. Iron coating to control disease will be developed as a new seed disinfection method to reduce the use of agricultural chemicals.