历史上,人们施用杀菌剂来预防由真菌引起的作物病害。如克菌丹和代森锰类主要用作保护剂,为了得到令人满意的防效,就必须在病原菌侵染前施用。由于在作物生长过程中,新的感染部位又会发生,当化学药物失效或被淋失时,以前的保护区又变得易感染,因此,这些药剂要经常施用。这些药剂通过种子包衣、复盖发芽幼苗表面和扩散到附近土壤中而作为种子处理剂,被成功地施用。某些具局部内吸的药剂,诸如萎锈灵,可渗入种子和防治种子传播的病害。 Historically, fungicides have been used to prevent crop diseases caused by fungi. Such as captan and dexmedetomidine mainly used as a protective agent, in order to get satisfactory control, it must be applied before the infection of pathogens. As new parts of the infection occur again during crop growth, the former protected areas become susceptible to infection again when the chemical becomes ineffective or is lost and therefore these agents are often applied. These agents are successfully applied by seed coating, covering the surface of sprouted seedlings and spreading into nearby soil as a seed treatment. Certain agents with systemic aspiration, such as carbendazim, penetrate seeds and control seed-borne diseases.