杀菌剂按作用原理可分为保护剂和治疗剂。保护剂在植物体表与病原菌接触 ,能消灭病原菌或防止病原菌侵入植物体内 ,使植物免受其害 ;治疗剂能在植物发病后 ,通过内吸作用或渗透作用进入植物体内 ,抑制或杀死病原菌 ,使病株不再受害。按成分及来源 ,杀菌剂可分为无机、有机及生? According to the principle of fungicide can be divided into protective agent and therapeutic agent. Protectant in the plant surface and pathogenic bacteria contact, can eliminate pathogens or prevent pathogenic bacteria invade plants, the plants from harm; the therapeutic agent can plant pathogenesis, by systemic action or infiltration into the plant, inhibit or kill Pathogenic bacteria, so that diseased plants no longer suffer. According to the ingredients and sources, fungicides can be divided into inorganic, organic and raw?