植物病理学(Plant Pathology)是对于引起植物疾病的病原体（感染性微生物）和环境条件（生理因素）的科学研究 。引起感染性疾病的生物体包括真菌，卵菌，细菌，病毒，类病毒，病毒样生物，植原体，原生动物，线虫和寄生植物。不包括体外寄生虫像昆虫，螨类，脊椎动物，或其他害虫，会通过消费植物组织而影响植物健康。植物病理学主要认识并了解植物生病的原因，对人类社会与经济之关系，病原菌的鉴定，生理和生态特性、疾病的病因、疾病的周期、寄生性、致病性、植物抗病性、病害防治、病害系统遗传学、和植物病害管理等等的研究。

Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrate, or other pests that affect plant health by consumption of plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.