A professional who conducts research in nature, cause, and control of plant diseases and decay of plant products. Responsibilities include:

• Studies and compares healthy and diseased plants to determine symptoms of diseased condition.
• Inoculates healthy plants with culture of suspected agents taken from diseased plants and studies effects to determine agents responsible for disease.
• Isolates disease-causing agent, studies habits and life cycle, and devises methods of destroying or controlling agent (microbiologist).
• Tests possible control measures under laboratory and field conditions for comparative effectiveness, practicality, and economy.
• Investigates comparative susceptibility of different varieties of plants and develops varieties immune to disease (plant breeder).
• Studies rates of spread and intensity of disease under different conditions of soil, climate, and geography, and predicts outbreaks of plant diseases.
• Determines kinds of plants and insects that harbor or transmit disease.
• Studies losses from deterioration of perishable plant products in transit or storage and develops practices to prevent or reduce losses.
• Determines presence of disease producing agents in seed stocks to reduce losses from seed borne diseases.
• May specialize in type of plant affected, such as cereal crops, fruit, or forest trees, or by type of disease, such as bacterial, virus, fungus, mycoplasma, or nematode.
• May inspect flower and vegetable seeds and flowering bulbs for diseases, infections, and insect injuries.