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I. Introduction to disease control
A. Causes of Plant Diseases
1. Abiotic
a. Non-living cause of a plant disease by a physical or
chemical component of the environment that is harmful
to plant growth
b. By definition, abiotic diseases cannot spread from
plant to plant
c. Abiotic plant diseases could include:
Temperature extremes - winter kill, frost damage
Soil moisture extremes
Soil nutrient deficiencies or imbalance
Agricultural chemicals
Lightning, hail, wind, or pollutants
I. Introduction to disease control
A. Causes of Plant Diseases
1. Biotic
a. Living cause of a plant disease by a pathogen - any
living organism capable of causing disease in a
particular host species
b. Most biotic pathogens are parasites, which grow and
reproduce only on living plant tissues
c. Major groups of plant pathogens could include:
Fungi
Bacteria
Mycoplasmalike organisms
Viruses
Nematodes
I. Introduction to disease control
B. The disease triangle
1. Host plant
a. Type of grass or grasses that are affected by this
Disease (pathogen)
b. This is sometimes different within grass species different cultivars of the same species might have
different degrees of susceptibility
I. Introduction to disease control
B. The disease triangle
2. Pathogen
a. The disease causing organism
b. This could be a fungus, bacteria, virus, or non-living
agent. Parasitic or non-parasitic pathogen
I. Introduction to disease control
B. The disease triangle
3. Environment
a. Environmental conditions that favor the development
of the disease
b. These conditions might include temperature, humidity,
wind (or lack there of), time of the year, and moisture
content (either in the air or in the plant)
Locations for Testings
For times and locations for testing to obtain a Applicators
License, call your local Community College, or the
Department of Agriculture in your state.
Clackamas Community College:
503-657-6958 ex.2269
Mount Hood Community College:
503-491-7592
Portland Community College:
503-614-7289
Chemeketa Community College:
503-399-6556
ODA: 503-986-4635
Suggested Guidelines for Maintenance Staff
1. Be observant
2. Know and understand what healthy turf looks like
3. Report anything that looks different than healthy turf
4. Ask questions
5. Invest in a good pocket magnifying glass
6. Take the Turf Management Program at
Walla Walla Community College
Questions?
Walla Walla Community College
500 Tausick Way
Walla Walla, WA. 99362-9267
Bill Griffith
Instructor - Turf Management
Bus: (509) 527-4269
Res: (509) 525-5521
Fax: (509) 527-4572
e-mail: [email protected]