Agriculture Reference
In-Depth Information
ple, chemical controls are too costly. For other diseases, such as many
soil-borne pathogens, no economical or effective chemical control method is
available.
b.
Cultural Control
A pathogen and its host must be brought together under specific environ-
mental conditions for a plant disease to develop. Cultural practices are used to
alter the environment, the condition of the host, or the behavior of the patho-
gen to prevent an infection.
Crop Rotation
—Path ogenic organ isms nearl y alway s can be carri ed
over from one growing season to the next in the soil or in plant debris. Con-
tinual production of the same or closely related crops on the same piece of
land leads to a disease buildup. Crop rotation reduces the buildup of patho-
gens, but seldom provides complete disease control. Obviously, crop rotation
is not always possible, practical, or desirable. Perennial crops such as trees,
woody ornamentals and turfgrass must remain in one location for many years.
Some crops, such as corn, cotton, or wheat, often are more practical to grow
on the same land year after year despite the potential for a buildup of plant
disease pathogens.
Planting Time
—Cool-weather crops, such as spinach, peas, and some
turfgrass, are subject to attack by certain diseases if planted when the tempera-
tures are warmer. They often emerge and establish poorly under such condi-
tions. Conversely, beans, melons, and many flowers should be planted under
warm conditions to avoid disease.
Seed Aging
—Some seed pathogens can be deactivated by holding the
seed in storage. Proper storage conditions are essential to ensure that seed
viability is not lowered.
c.
Mechanical Control
Hot water treatments are effective in producing clean seed and planting
materials. Seed and vegetative propagation materials (such as roots, bulbs,
corms, and tubers) may be treated before planting to eliminate some fungal,
bacterial, and viral diseases.
d.
Sanitation
Pathogen-Free Seed Stock
—Production
of clean seed stock is impor-
tant in reducing plant disease spread. Often, seeds are grown in arid areas
where the amount of moisture is controlled by an irrigation system. This
