AGRICULTURAL CROP DISEASE MANAGEMENT CATEGORY 1C FINAL
PAPER 2025/2026 QUESTIONS WITH SOLUTIONS GRADED A+
✔✔ plant disease - ✔✔any abnormal condition that damages a plant and alters its
appearance or function, or reduces its productivity
✔✔Symptoms - ✔✔The visible effects of a plant disease on the host plant
✔✔Pathogen - ✔✔The parasitic organism that causes a disease.
✔✔Plant disease triangle - ✔✔Susceptible host, pathogen, & favorable environment
✔✔Host - ✔✔Plant invaded by the pathogen and serving as its food source.
✔✔Pathogen - ✔✔The Parasitic organism that causes a disease. Certain fungi,
bacteria, viruses and nematodes are _________of field crops in Iowa
✔✔favorable environment - ✔✔Temperature and moisture are the most important
environmental factors that affect development of most diseases
✔✔Fungi - ✔✔Largest and perhaps the most familiar group of plant pathogens. Most
reproduce by forming spores.
✔✔Bacteria - ✔✔extremely small microorganisms, require a microscope to be seen,
reproduce by simple division or splitting of the cell into two equal halves. Spread from
plant to plant by wind drivien rain and gain entrance into plant tissues through natural
plant openings
✔✔Plant tissue wounds - ✔✔wounds in plant tissues from insects, hail, wind, or other
causes provide entry for bacteria.
✔✔Bacterial diseases common in Iowa - ✔✔Bacterial wilt of alfalfa, bacterial blight,
pustule of soybean, holcus leave spot on corn, and stewart's wilt on corn
✔✔Viruses - ✔✔Infectious, disease producing particles that are very small, measuring
about one millionth of an inch. Multiply by inducing the host cells to form more viruses.
✔✔Vectors - ✔✔An organism that transmits disease by conveying pathogens from one
host to another
✔✔Nematodes - ✔✔Round, slender threadlike worms. Found in soil, fresh and salt
water, in or on plants and in animals.
✔✔Stylet - ✔✔The needlelike mouth part of a nematode.
, ✔✔Stubby root nematode - ✔✔causes the root system of plants to become enlarged
and shortened i.e. stubby
✔✔Soybean Cyst Nematode - ✔✔most destructive nematode disease in Iowa field
crops
✔✔Noninfectious Disorders - ✔✔Caused by nonliving agents, might be caused by any
physical or chemical component of the environment that is harmful to the plant's growth
and development. (examples Temperature & moisture extremes, hail, wind, lightning,
unfavorable light, improper soil nutrient levels, toxic chemicals and mechanical damage
✔✔Symptoms of noninfectious disorders - ✔✔May appear suddenly and often occur in
patterns. Wilting, stunting, yellowing, plant tissue deformation, or death of plant tissue.
✔✔Inoculum - ✔✔Any material capable of producing infection and causing disease.
✔✔Incubation period - ✔✔Period between infection and the first appearance of
symptoms.
✔✔Means of pathogen survival - ✔✔Soil, Crop residues, weed or noncrop hosts, seed
and vegetative plant parts, insets, mild climates.
✔✔How are field crop diseases diagnosed - ✔✔visual symptoms or signs combined
with knowledge of diseases likely to infect crops in the area. Best way is to identify the
pathogen
✔✔Four steps of diagnosing suspected plant disease - ✔✔1. Make observations
(identify the diseased plant)
2. Examine individual plants
3. Collect background or crop history
4. Diagnose problem
✔✔integrated pest management - ✔✔An agricultural practice that uses a variety of
techniques designed to minimize pesticide inputs
✔✔Scouting - ✔✔Is the monitoring of the crop and pest conditions on a regular basis
throughout the year.
✔✔Management options for plant diseases - ✔✔1. Regulatory or legal methods,
including Quarantines and inspections, & seed certification.
2. Biological methods. Resistant varieties, Biological control agents.
3. cultural methods. Crop rotation, crop residue management, cultivation, sanitation.
proper harvest, proper storage.
4. Chemical control. Use of fungicides
PAPER 2025/2026 QUESTIONS WITH SOLUTIONS GRADED A+
✔✔ plant disease - ✔✔any abnormal condition that damages a plant and alters its
appearance or function, or reduces its productivity
✔✔Symptoms - ✔✔The visible effects of a plant disease on the host plant
✔✔Pathogen - ✔✔The parasitic organism that causes a disease.
✔✔Plant disease triangle - ✔✔Susceptible host, pathogen, & favorable environment
✔✔Host - ✔✔Plant invaded by the pathogen and serving as its food source.
✔✔Pathogen - ✔✔The Parasitic organism that causes a disease. Certain fungi,
bacteria, viruses and nematodes are _________of field crops in Iowa
✔✔favorable environment - ✔✔Temperature and moisture are the most important
environmental factors that affect development of most diseases
✔✔Fungi - ✔✔Largest and perhaps the most familiar group of plant pathogens. Most
reproduce by forming spores.
✔✔Bacteria - ✔✔extremely small microorganisms, require a microscope to be seen,
reproduce by simple division or splitting of the cell into two equal halves. Spread from
plant to plant by wind drivien rain and gain entrance into plant tissues through natural
plant openings
✔✔Plant tissue wounds - ✔✔wounds in plant tissues from insects, hail, wind, or other
causes provide entry for bacteria.
✔✔Bacterial diseases common in Iowa - ✔✔Bacterial wilt of alfalfa, bacterial blight,
pustule of soybean, holcus leave spot on corn, and stewart's wilt on corn
✔✔Viruses - ✔✔Infectious, disease producing particles that are very small, measuring
about one millionth of an inch. Multiply by inducing the host cells to form more viruses.
✔✔Vectors - ✔✔An organism that transmits disease by conveying pathogens from one
host to another
✔✔Nematodes - ✔✔Round, slender threadlike worms. Found in soil, fresh and salt
water, in or on plants and in animals.
✔✔Stylet - ✔✔The needlelike mouth part of a nematode.
, ✔✔Stubby root nematode - ✔✔causes the root system of plants to become enlarged
and shortened i.e. stubby
✔✔Soybean Cyst Nematode - ✔✔most destructive nematode disease in Iowa field
crops
✔✔Noninfectious Disorders - ✔✔Caused by nonliving agents, might be caused by any
physical or chemical component of the environment that is harmful to the plant's growth
and development. (examples Temperature & moisture extremes, hail, wind, lightning,
unfavorable light, improper soil nutrient levels, toxic chemicals and mechanical damage
✔✔Symptoms of noninfectious disorders - ✔✔May appear suddenly and often occur in
patterns. Wilting, stunting, yellowing, plant tissue deformation, or death of plant tissue.
✔✔Inoculum - ✔✔Any material capable of producing infection and causing disease.
✔✔Incubation period - ✔✔Period between infection and the first appearance of
symptoms.
✔✔Means of pathogen survival - ✔✔Soil, Crop residues, weed or noncrop hosts, seed
and vegetative plant parts, insets, mild climates.
✔✔How are field crop diseases diagnosed - ✔✔visual symptoms or signs combined
with knowledge of diseases likely to infect crops in the area. Best way is to identify the
pathogen
✔✔Four steps of diagnosing suspected plant disease - ✔✔1. Make observations
(identify the diseased plant)
2. Examine individual plants
3. Collect background or crop history
4. Diagnose problem
✔✔integrated pest management - ✔✔An agricultural practice that uses a variety of
techniques designed to minimize pesticide inputs
✔✔Scouting - ✔✔Is the monitoring of the crop and pest conditions on a regular basis
throughout the year.
✔✔Management options for plant diseases - ✔✔1. Regulatory or legal methods,
including Quarantines and inspections, & seed certification.
2. Biological methods. Resistant varieties, Biological control agents.
3. cultural methods. Crop rotation, crop residue management, cultivation, sanitation.
proper harvest, proper storage.
4. Chemical control. Use of fungicides
