Strategies for disease control in crops
Understanding the big picture can help you reduce crop losses from plant diseases.
The crop season of 2013 is drawing to a close. Harvest activities are progressing well and farmers are looking forward to successful completion of field work. Soon, it will be time to put together orders for next year’s inputs, seed, plant nutrients, equipment parts and other inputs.
This fall’s field operations can have a distinct impact on potential disease pressure in your fields next year and in years to come. Burying crop residues is an ancient practice intended to reduce plant diseases in following years. However, increased interest in minimum and no-till practices has resulted in less incorporation of residues. Along with developments in crop production practices, understanding of plant disease has also increased. Farmers are responsible for their own decisions related to these types of situations and should have an understanding of strategies for controlling crop diseases.
Basically, an overall strategy for crop disease management might include the following three components:
- Reduce the initial plant disease inoculum.
- Reduce the infection rate.
- Reduce the duration of the epidemic.
Each of these components can be further developed using traditional principles of plant disease control, for example:
1. Reduce the initial plant disease inoculum.
- Avoidance. Reduce the level of disease by selecting a season or a site where the amount of inoculum is low or where the environment is unfavorable for infection.
- Exclusion. Reduce the amount of initial inoculum introduced from outside sources.
- Eradication. Reduce the production of initial inoculum by destroying or inactivating the sources of initial inoculum (sanitation, removal of reservoirs of inoculum, removal of alternate hosts, etc.).
- Protection. Reduce the level of initial infection by means of a toxicant or other barrier to infection.
- Resistance. Use cultivars that are resistant to infection, particularly the initial infection.
- Therapy. Use thermotherapy, chemotherapy or meristem culture to produce certified seed or vegetative planting stock
2. Reduce the infection rate.
- Avoidance. Reduce the rate of production of inoculum, the rate of infection or the rate of development of the pathogen by selecting a season or a site where the environment is not favorable.
- Exclusion. Reduce the introduction of inoculum from external sources during the course of the epidemic.
- Eradication. Reduce the rate of inoculum production during the course of the epidemic by destroying or inactivating the sources of inoculum (roguing).
- Protection. Reduce the rate of infection by means of a toxicant or some other barrier to infection.
- Resistance. Plant cultivars that can reduce the rate of inoculum production, the rate of infection or the rate of pathogen development.
- Therapy. Cure the plants that are already infected or reduce their production of inoculum.
3. Reduction of the duration of the epidemic.
- Avoidance. Plant early maturing cultivars or plant at a time that favors rapid maturation of the crop.
- Exclusion. Delay the introduction of inoculum from external sources by means of plant quarantine.