Diseases and Management Practices
Scouting
Scouting provides the critical necessary information on diseases present, severity of
diseases, and potential crop loss if untreated. This information is essential before
investing in chemical control or making practices.
Scouting of wheat fields for disease should be undertaken weekly from Zadok's Growth Stage 30 (Feekes' Growth Stage 5) until
physiological maturity to justify the use of fungicide application for disease control.
The most important time a wheat producer can have during this period of crop development
is the twenty minutes per field per week scouting for disease. The information gained from
weekly scouting will prevent the unnecessary use and expense of fungicide application or
ensure that a fungicide application is made when it will provide the greatest economic
return.
Scouting requires examination of 6 to 10 randomly selected sites that represent the
character of plants within the field. Examine closely the leaves of each of the tillers
selected. The use of a magnifying glass or hand lens may be particularly useful,
especially when first beginning to scout. Determine and make a record of the following:
 Wheat growth
stage:
A sharp pocket knife or a single-edged razor blade is
useful to split open plants to determine the stage of growth after jointing.
Which diseases are
present:
- Check disease photographs and descriptions.
Disease severity
Control options:
- Consult Extension Service personnel and other local experts. Always
follow label directions for disease control recommendations.
Begin a course of action
- Only when you are fully "armed" with up-to-date, accurate
information.
Check crop response to
your disease control practice.
- Leave a non-treated strip for comparison.
Sanitation
Bury pathogen-infested crop residues by tillage or plow down. This practice is useful to
reduce risk from Septoria leaf and glume blotch, tan spot and scab.
Rotation
Avoid presence of pathogens by not following wheat with wheat or corn with wheat. This
practice reduces risk from scab, Septoria leaf and glume blotch, take-all and tan spot.
Planting date
Avoid pathogen or reduce the infection period. Avoidance of early planting is particularly
effective in reducing the risk and impact of barley yellow dwarf, wheat spindle streak and
powdery mildew infections.
Seedbed preparation
provide good seed to soil contact and fertility to promote vigorous plant stands.
Good quality,
disease-free seed
Promote healthy, vigorous seedling development. This will start wheat free of seedling
diseases, reduce potential for Septoria leaf and glume blotch, and control loose smut.
Adapted, disease
resistant cultivars
Produce plants able to resist disease attack. However, no cultivar is resistant to all
diseases or is disease resistant "forever". The use of resistant cultivars can
reduce losses from leaf rust, powdery mildew, barley yellow dwarf and wheat spindle streak
and may reduce the need for foliar fungicide applications.
Seed treatment
fungicides
Depending on the fungicide, this practice will protect developing seedlings from root
rots, powdery mildew infections and loose smut.
Foliarly-applied
fungicides
Fungicides can protect the yield established when management practices and cultivar
resistance will not prevent economically significant losses from occurring.
Foliarly-applied fungicides should be used only when the potential for loss is eminent.
This requires the regular scouting of fields for disease, identification, incidence, and
severity, and stage of growth of the wheat crop in order to make the decision to apply a
fungicide.
Summary
The effectiveness of the various management and cultural practices on
the control of the diseases commonly occurring in the humid, Eastern wheat production area
is summarized in following table. |
