Ohio State University Extension Bulletin

Ohio Pesticide Applicator Training
Field Crops
Student Workbook

Bulletin 821

Field Crop Diseases

Author:
Roger Bender
Extension Agent, Agriculture
  1. Which of the following conditions make soybeans more susceptible to Phytophthora root rot?
    1. Significant soil compaction
    2. Excessive rainfall
    3. Lack of resistance
    4. B and C
    5. A, B and C

    Answer

  2. The disease generally most damaging to field corn is:
    1. Leaf blight
    2. Stalk rot
    3. Root rot
    4. None of the above

    Answer

  3. Fungicides are:
    1. Pesticides
    2. Insect control agents
    3. Disease control products
    4. Harmless
    5. A and C

    Answer

  4. Corn leaf blight can be effectively controlled by proper hybrid selection.
    1. True
    2. False

    Answer

  5. Which of the following are wheat diseases?
    1. Stewart's wilt
    2. Powdery mildew
    3. Sclerotinia
    4. Leaf rust
    5. B and D

    Answer

  6. Optimum disease control can be enhanced by:
    1. Proper fertilization
    2. Improved weed control
    3. Proper seed bed preparation
    4. All of the above
    5. None of the above

    Answer

  7. Using rotation sequence of two or more years:
    1. Increases the incidence of take-all in wheat
    2. Favors the development of Cephalosporium stripe
    3. Reduces the fungal carryover of take-all and stripe
    4. None of the above

    Answer

  8. Clean tillage does not help reduce fungus diseases in "grain" crops.
    1. True
    2. False

    Answer

  9. Which of the following is not an important oat disease?
    1. Sclerotinia
    2. Loose smut
    3. Crown rust
    4. Barley yellow dwarf
    5. None of the above

    Answer

  10. Head scab in wheat:
    1. Is not preventable by use of resistant varieties
    2. Is usually more severe when wheat is planted after corn
    3. A and B
    4. None of the above

    Answer

  11. Phytophthora damping-off and root rot is the most destructive soybean disease in Ohio.
    1. True
    2. False

    Answer

  12. Delayed germination can increase seedling disease prevalence in corn, soybeans, wheat and oats.
    1. True
    2. False

    Answer

  13. Major corn diseases include:
    1. Ear rot
    2. Leaf blight
    3. Stalk rots
    4. All of the above
    5. None of the above

    Answer

  14. The Gibberella fungus:
    1. The Gibberella fungus:
    2. Causes head scab in wheat
    3. Can cause stalk rot in corn
    4. A, B, and C
    5. A and C

    Answer

  15. Sclerotinia stem rot in soybeans:
    1. Develops as a white mold creating a lesion that girdles the stem
    2. Can be controlled with use of resistant varieties
    3. Can be controlled in no-till conditions with a two-year rotation
    4. A and B
    5. A and C

    Answer

  16. The use of fungicides is the primary control method of field crop diseases.
    1. True
    2. False

    Answer

  17. Corn virus diseases are often more severe in fields heavily infested with johnsongrass and:
    1. Can be transmitted by aphids and leafhoppers
    2. Are controlled by the use of resistant and tolerant hybrids
    3. Include maize dwarf mosaic and maize chlorotic dwarf
    4. All of the above
    5. None of the above

    Answer

  18. No chemical control methods are recommended for soybean leaf diseases.
    1. True
    2. False

    Answer

  19. Excessive use of nitrogen fertilizer in wheat favors:
    1. Septoria
    2. Powdery mildew
    3. Leaf rust
    4. A and B
    5. B and C

    Answer

  20. Disease in a field crop most likely occurs when:
    1. Resistant varieties are grown
    2. Environmental conditions favor infection
    3. Pathogens attack a vulnerable plant
    4. B and C
    5. All of the above

    Answer

  21. Phomopsis seed decay in soybeans:
    1. Can result in poor germination and emergence
    2. Occurs when wet weather persists during soybean dry-down and maturation
    3. Is caused by bacteria and viruses
    4. A and B
    5. A, B, and C

    Answer

  22. Which of the following tends to increase the possibility of corn stalk rot?
    1. Stalk borers
    2. Continuous corn
    3. Soil potassium level of 300 lbs. K/A (150 PPM)
    4. A, B, and C
    5. A and B

    Answer

  23. Planting corn, soybeans and wheat seed that has a high germination will have insignificant effect on the likelihood of seedling disease.
    1. True
    2. False

    Answer

  24. Proper identification of diseases:
    1. Takes too long if the corrective treatment is to be timely
    2. Is not necessary if broad spectrum fungicides are used
    3. Has little to do with long-term prevention and control strategies
    4. All of the above
    5. None of the above

    Answer

  25. Widespread outbreaks of Rhizoctonia root rot in soybeans usually occurs:
    1. When we have a wet growing season
    2. When weather is dry in early spring and wet later in the season
    3. When weather is wet in early spring and dry later in the season
    4. None of the above

    Answer

  26. Hot, rainy weather from mid-April through flowering favors the development of wheat diseases such as powdery mildew, leaf rust, septoria and head scab.
    1. True
    2. False

    Answer

  27. Seedborne disease problems can be reduced by:
    1. Planting seed deeper when soil is cold
    2. Utilization of fungicide seed treatments
    3. Ensuring optimum seed to soil contact to improve germination
    4. A, B, and C
    5. B and C

    Answer

  28. Integrated Pest Management (IPM) practices should be used for all crop pest control, including diseases, insects and weeds.
    1. True
    2. False

    Answer

  29. When planning a crop disease management strategy, a farmer should:
    1. Refer to field histories in planning rotations and fertilization
    2. Obtain hybrid and varietal publications from Extension and private sources to assist in selecting seed supplies
    3. Collect publications with color identification photographs
    4. Obtain correct identification of disease problems that have occurred on the farm
    5. All of the above

    Answer

  30. The impact of Sudden Death Syndrome (SDS) is best managed by
    1. Reducing soybean cyst nematode populations
    2. Crop rotation
    3. Improving soil drainage
    4. All of the above
    5. None of the above

    Answer

  31. Soybean cyst nematode populations
    1. Can increase if winter annual weeds are not controlled properly
    2. Are not reduced by crop rotation
    3. Are best controlled by using resistant varieties
    4. B and C

    Answer

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Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture

All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.

Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.

TDD No. 800-589-8292 (Ohio only) or 614-292-1868


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