大多数作物因受真菌、细菌、类菌质体和病毒等各种病原物的侵染而导致产量或质量不同程度的降低。多年来,使用保护杀菌剂能够直接防治真菌病害。近年来,随着内吸杀菌剂的发现和使用,真菌病害的防治已经取得令人注目的进展。抗生素亦可用来直接防治细菌病害(例如火疫病和晕圈疫病),如四环素类抗生素已被用来防治由类菌质体引起的梨枝干枯病。 Most crops due to fungal, bacterial, fungal and viral pathogens such as infection led to varying degrees of yield or quality reduction. Over the years, the use of protective fungicides can directly control fungal diseases. In recent years, with the discovery and use of systemic fungicides, remarkable progress has been made in the control of fungal diseases. Antibiotics can also be used to directly control bacterial diseases (such as fire blight and halo disease), such as tetracycline antibiotics have been used to control pear-shaped stem blight caused by the mycoplasma.