Plant disease management, like most pest management, is based on several important principles. While plant disease control is often not practical or even possible, it may be possible to reduce the progress of the disease and keep it at an acceptable level. Below are the basic principles of plant disease management.

Exclusion

Exclusion of plant diseases consists of practices designed to keep pathogens (things that cause disease), vectors (things that spread disease) and infected plants out of disease-free areas. The goal of this method of management is to prevent the disease from entering the area where the plants are growing. For example, never plant diseased or infested plants. Another method is to establish plants in areas where the disease organism does not occur.

Eradication

Eradication consists of eliminating, destroying or inactivating a disease organism after it has become established. This includes:

Destruction of infected plants
Disinfection of storage bins, containers and equipment
Soil disinfection by fumigation, pasteurization, solarization or drenching

Since complete eradication is not always possible or economically feasible, this control method also includes reduction of the disease organism to an acceptable level. Reducing the level of infestation involves cultural practices, such as sanitation, removing diseased plants or plant parts, rotating crops, eliminating weeds or other plants that may be alternate hosts for the disease, and discouraging or preventing insect vectors.

Protection

Protection establishes a chemical or physical barrier between the host and the cause of the disease. For example, there are chemical applications available to prevent a disease from becoming established, such as fungicidal dusts and nematicides (nematode controls). Row covers that exclude insects that carry disease, fences and other physical barriers also provide protection from pests.

Resistance

This method of control focuses on planting resistant varieties. Resistance is achieved by altering the genetic system of the host to make it less susceptible to the disease organism. The tomato packet shows a strain of tomato developed to be resistant to the diseases, verticillium and fusarium wilt (VF). Some varieties are labeled "VFN" and are also resistant to nematodes.

There are two types of resistance used in plant disease management. Vertical resistance provides very high level resistance, or immunity, to specific strains of disease organisms. Horizontal resistance is a lower level of resistance, or tolerance, to many more strains of disease organisms. Both types of resistance are used in the development of agricultural crop plants. There are also many trees, shrubs, and ornamental and vegetable crops with resistant varieties on the market.

Therapy

This method of plant disease management is achieved by incorporating a chemical control agent into the physiological processes of the plant to reverse the progress of disease development after infection has occurred. Use of this principle is limited by the relatively small number of systemic materials available.

Avoidance

Photo of a woman hadn watering plants with a hose

This method of plant disease management includes cultural practices that help avoid the potential for infection. Practices such as planting date selection, seedbed preparation and water management are cultural practices that help avoid disease. Poorly drained soils, shade and other factors can increase the susceptibility of plants to disease. Place plants properly or remove and replace problem plants with better-adapted species. 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.

Hefner, M. 2019, Plant Disease Management, Extension | University of Nevada, Reno. IP

Authors of this scholarly work are no longer available.

Please contact Extension's Communication Team for assistance.

Also of Interest:


*A Northern Nevada Homeowner's Guide to Identifying and Managing Cabbage Caterpillars* This fact sheet describes the identifying features, life cycle, plant damage, and control methods for managing common caterpillar pests on various crops in the cabbage family. K. Burls, W. Hanson Mazet, H. Kratsch 2021, Extension, University of Nevada, Reno, FS-21-109
*A Northern Nevada Homeowner's Guide to Identifying and Managing Earwigs* This fact sheet describes the identifying features, life cycle, plant damage, and control methods for managing earwigs in Nevada. K. Burls, W.Hanson Mazet, H. Kratsch 2021, Extension, University of Nevada, Reno, FS-21-108
*A Northern Nevada Homeowner's Guide to Identifying and Managing Shield Bugs* This fact sheet describes the identifying features, life cycle, plant damage, and control methods for managing Shield Bugs in Nevada. K. Burls, W. Hanson Mazet, H. Kratsch 2021, Extension, University of Nevada, Reno, FS-21-110
*A Northern Nevada Homeowner's Guide to Identifying and Managing Squash Bugs* This fact sheet describes the identifying features, life cycle, plant damage, and control methods for managing Squash Bugs in Nevada. K. Burls, W. Hanson Mazet, H.i Kratsch 2021, Extension, University of Nevada, Reno, FS-21-111
*Nevada Noxious Weed Field Guide – Mayweed chamomile* Mayweed chamomile is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed. Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2021, Extension, University of Nevada, Reno, Field Guide

Associated Programs

ladybug larva eating aphids on a pepper plant

Integrated Pest Management

Integrated Pest Management program is a long-term management strategy that uses a combination of tactics to reduce pests to tolerable levels with potentially lower costs for the pest manager and minimal effect on the environment.

Plant Disease Management