Plant diseases can be managed using a combination of cultural, biological, and chemical procedures. Once disease-causing organisms infect plants, very few treatments will cure the disease. It may be possible to reduce the progress of a plant disease and keep it at an acceptable level.
Exclusion — keep pathogens (things that cause disease), vectors (things that spread disease) and infected plants out of disease-free areas.
Eradication — destroy a disease organism after it has become established. You can do this by destruction of infected plants, disinfection of storage bins, containers and equipment, and/or soil disinfection by fumigation, pasteurization, solarization or drenching.
Protection – use a physical barrier such as a row cover. You can also use chemical applications available to prevent a disease from becoming established.
Resistance — plant resistant varieties.
Therapy – use chemicals that are systemic in the plant.
Avoidance – use good cultural practices such as planting date selection, seedbed preparation and water management to avoid disease. Poorly drained soils, shade and other factors can increase the susceptibility of plants to disease. Provide adequate irrigation, fertilization and space for each plant. Handle plants carefully to prevent injury, as the injury may later be the access point for a disease.
Compost teas are actively brewed to produce beneficial microbes. See Notes on Compost Tea, National Sustainable Agriculture Information Service
Tomato Spotted Wilt Virus has increasingly been found in home gardens. The most noticeable symptoms are yellow rings or spots on fruit. For more information, see Greenhouse Plant Viruses (TSWV/INSV) .
Soil solarization is a nonchemical method for controlling soil borne fungal diseases and nematodes, during hot summer months.
Winter damage to conifers — a video from the CSU Plant Diagnostic Clinic