PROBLEM TO BE SOLVED: To provide a technique about microbial pesticides which is effective in bacterial disease damages developing in raising seedling-period of Poaceae plants and has less environmental loads.SOLUTION: The above subject is solved by a bacterial disease control agent for controlling the bacterial disease damages of Poaceae plants which contains at least one selected from the group consisting of a culture medium or bacterial-cell suspension of Herbaspirillum sp. s4, or the supernate fluid of the culture medium； a control method of bacterial disease damages of Poaceae plants which has a control treatment step of adhering Poaceae seeds to the bactericidal control agent； and furthermore, seeds of Poaceae plants coated with the bacterial disease control agent.SELECTED DRAWING: None【課題】イネ科植物の育苗期に発生する細菌性病害に有効であり、かつ、環境負荷の少ない微生物農薬に関する技術を提供する。【解決手段】ハーバスピリラム・エスピー（Herbaspirillum sp.）s4株の培養液、菌体懸濁液又は前記培養液の上清液からなる群から選択された少なくとも１種を含み、イネ科植物の細菌病害を防除するための細菌病防除剤、該細菌病防除剤にイネ科植物の種子を付着させる防除処理工程を有するイネ科植物の細菌性病害の防除方法、さらに細菌病防除剤をコートしたイネ科植物の種子により解決する。【選択図】なし
