AGH 483
Exam 1
20 September 2009
Please write your name
on the back of the exam
50-point exam; each question worth 0.8 points
Chapter 1 Introduction and Diagnosis of Disease, and Video on
Diseases of Landscape Ornamentals
Matching. Place the letter(s) of the phrase or phrases that best matches the description in the
space next to the description. Phrases may be used more than once or not at all.
A.
B.
C.
D.
E.
Anthracnose
Blight
Canker
Chlorosis
Damping-off
_______1.
Dead or roughened area on the trunk or stem.
_______2.
Death of seedlings or cuttings.
_______3.
Rapid killing of plant tissue.
Matching. Place the letter(s) of the phrase or phrases that best matches the description in the
space next to the description. Phrases may be used more than once or not at all.
A.
B.
C.
D.
E.
Mosaic
Necrosis
Ring Spot
Rust
Water soaking
_______4.
Death of plant tissue.
_______5.
Spot on a leaf that appears ‘greasy’ or wet, and a common symptom of
bacterial infections.
_______6.
Uneven coloration or patterns on leaves, with small yellow or yellow-green
patterns or streaks, usually caused by a virus.
1
True/false questions. Please read each statement carefully then on the line next to the
statement place a T if the statement is true or an F if the statement is false.
_______7.
The germ theory of disease states that microscopic pathogens cause most
infectious diseases in plants.
_______8.
Viruses are nonobligate parasites.
_______9.
Drought is a main contributor to blights and canker diseases in woody plants.
_______10. Fungi and bacteria are often spread upward in a canopy by sprinkler irrigation
or splashing raindrops.
Multiple choice questions. Please read each question carefully then place the letter of the
answer that best completes the statement in the blank beside the question.
_______11. Which of the following disease classification categories are considered the
most useful?
A.
Plant organ the disease affects.
B.
Symptoms the disease causes.
C.
Time of year the disease occurs.
D.
Type of pathogen.
E.
Types of plants affected.
_______12. A microbe found on a diseased plant may have caused the disease but you
cannot find published information verifying this. Which procedure do you
follow to determine whether this pathogen caused this disease?
A.
Draw numbers out of a hat.
B.
Fungal determinant.
C.
Karnal’s rules.
D.
Koch’s postulates.
E.
Moist chamber.
_______13. Abiotic diseases include
A.
Crotch rot in various tree species.
B.
Improper fertilization.
C.
Leaf scorch caused by drought or high winds.
D.
Phomopsis tip blight caused by the Phomopsis fungus.
E.
Answers B and C are correct.
_______14. Most
A.
B.
C.
D.
E.
plant diseases are caused by
Bacteria.
Fungi.
Mollicutes.
Parasitic higher plants.
Viruses.
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_______15. It is speculated that the Salem, Massachusetts witchcraft trials in 1692 may
have been caused by the consumption of flour contaminated by mycotoxins
produced by
A.
Ergot.
B.
Fusarium.
C.
Oak wilt.
D.
Stachybotrys.
E.
Xylella.
_______16. Late blight of potato, one of the most devastating plant diseases in the history
of humanity, is caused by
A.
Improper planting practices.
B.
Leprechauns or fiendish locomotives racing through the countryside.
C.
The bacterium Erwinia amylovara.
D.
The fungus Anthracnose leafspotia.
E.
The fungus Phytophthora infestans.
_______17. Control methods for most fungal diseases, according to Dr. Mooreman of the
Pennsylvania State University (the video), include
A.
Cutting infected leaves or branches off of a plant.
B.
Keeping plants well watered with overhead sprinkler irrigation.
C.
Preventative fungicide spray program.
D.
Answers A and C are both true.
E.
All of the above are true.
_______18. Plant pathology is the study and control of ______________________ that
cause disease.
A.
Abiotic and environmental factors.
B.
Biotic and abiotic factors.
C.
Living and nonliving factors.
D.
Microbes and weather factors.
E.
All of the above are true.
_______19. When cutting or pruning infected plants, it is important to always
A.
Clean tools with alcohol or bleach solution in between cuttings.
B.
Cut branches on a slant.
C.
Remove an excess amount of plant material.
D.
Wear gloves.
E.
None of the above is true.
_______20. An aflatoxin is a
A.
Biological control method against fungi.
B.
Mycotoxin.
C.
Substance produced by certain types of fungi that may cause cancer in
some animals.
D.
Toxin used to control some plant diseases.
E.
Answers B and C are both true.
3
Chapter 2
Parasitism and Disease Development
Multiple choice questions. Please read each question carefully then place the letter of the
answer that best completes the statement in the blank beside the question.
_______21. Signs of a disease include
A.
Bleaching of wood caused by white rot fungi.
B.
Dead needles on conifers caused by Phomopsis Tip Blight.
C.
Water-soaked spots on ivy leaves.
D.
Both B and C are correct.
E.
None of the above is correct.
_______22. An antagonistic microorganism
A.
Attacks and injures plants.
B.
Attacks or repels plant pathogens.
C.
Attacks the farmers tending the crops.
D.
Typically lives on aerial parts of plants.
E.
All of the above may be true.
True/false questions. Please read each statement carefully then on the line next to the
statement place a T if the statement is true or an F if the statement is false.
_______23. The components of the disease triangle are temperature, wind and
rainfall/irrigation.
_______24. Inoculation ≠ infection.
_______25. An obligate parasite can feed off of either living or dead tissue.
_______26. Huitlacoche (pronounced wee-tlah-KOH-cheh) is an edible product formed by
a species of fungus.
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Chapter 3
How Pathogens Attack Plants
Multiple choice questions. Please read each question carefully then place the letter of the
answer that best completes the statement in the blank beside the question.
_______27. Pectinase is an enzyme produced by pathogens to break down this structure.
A.
Cell membrane.
B.
Middle lamella.
C.
Pectinophyll.
D.
Roots.
E.
Vascular tissue.
_______28. The pathogen responsible for Fire Blight on apples, crabapples and other
members of the Malus family is
A.
Canis felinus.
B.
Erwinia amylovora.
C.
Fusarium oxysporum.
D.
Phytophthora infestans.
E.
Ustilago maydis.
_______29. Soft rot pathogens typically use which type of chemical weapon to obtain
nutrition from harvested fruits and vegetables?
A.
Anthrax.
B.
Enzymes.
C.
Growth regulators.
D.
Polysaccharides.
E.
Toxins.
_______30. Fungi
A.
B.
C.
D.
E.
sometimes produce this enzyme to penetrate the plant surface.
Cutinase.
Gluconase.
Pectinase.
Polysaccharase.
Rubisco.
_______31. The feedback effect occurs when
A.
A plant produces glucose to counteract the effect of an enzyme or
toxin produced by a pathogen.
B.
Enzymes released by the pathogen break down plant substances and
the breakdown process triggers a large increase in production of the
enzyme.
C.
Pathogens that have penetrated the surface of the plant send signals to
pathogens still on the surface.
D.
The pathogen is able to complete one or more life cycles in one
growing season.
E.
The plant signals to neighboring plants that it is under attack.
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Chapter 4
Effect of Pathogens on Plant Physiology
Multiple choice questions. Please read each question carefully then place the letter of the
answer that best completes the statement in the blank beside the question.
_______32. Which kind of disease is most likely to cause a direct decrease in
photosynthesis on the host plant?
A.
Crown gall.
B.
Leaf spot.
C.
Root rot.
D.
Viral canker.
E.
Witches’ broom.
_______33. These
A.
B.
C.
D.
E.
fungi cause damage to wood by producing enzymes that degrade lignin.
Brown rot fungi.
Soft rot fungi.
White rot fungi.
Answers A and B are true.
All of the above are true.
True/false questions. Please read each question carefully then on the line next to the
statement place a T if the statement is true or an F if the statement is false.
_______34. The hypersensitive response is when a plant causes some cells to die in an
attempt to prevent the spread of a pathogen.
_______35. Plants attacked by many fungal and bacterial diseases quickly begin producing
larger quantities of enzymes and other proteins than are produced by plants
not under attack.
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Chapter 5
How Plant Defend Themselves against Pathogens
Matching. Place the letter of the phrase that best matches the description in the space next
to the description.
A.
B.
C.
D.
Preexisting plant structure
Induced plant structure
Preexisting biochemical defense
Induced biochemical defense
_______36. Detoxification of pathogen toxins.
_______37. Sclerenchyma bundles in the stems.
_______38. Superoxide radical.
_______39. Waxy surface.
_______40. Reinforcement of cell walls.
True/false questions. Please read each statement carefully then on the line next to the
statement place a T if the statement is true or an F if the statement is false.
_______41. Diseases typically cause a decrease in respiration.
_______42. Gum is a phenolic polysaccharide material deposited in some plant cell walls
in response to wounds or infections.
_______43. Plants use phenolic compounds to defend themselves against pathogenic
microbes.
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Chapter 6—Genetics of Plant Disease
Matching. Place the letter(s) of the phrase or phrases that best matches the
description in the space next to the description.
A.
B.
C.
D.
E.
Escape
Gene-for-gene concept
Horizontal resistance
Tolerance
Vertical resistance
_______44. Changes in the virulence of a pathogen appears to be continually balanced by
changes in the resistance of the host, and vice versa.
_______45. Plant varieties that are very resistant to certain races of a pathogen but are
susceptible to other races of the same pathogen.
_______46. This type of genetic resistance usually makes plants resistant to a greater
number of pathogen species.
_______47. Tomato plant develops necrotic spots on foliage and some yellowing but still
produces acceptable crop.
_______48. This type of resistance will probably break down relatively quickly.
_______49. A plant is very susceptible to a pathogen whose spores have landed on its leaf
surface but the weather is dry and the spores cannot germinate successfully.
_______50. The plant inactivates or compensates for the damage caused by a pathogen.
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Handouts and Campus Field Trip
True/false questions. Please read each statement carefully then on the line next to the
statement place a T if the statement is true or an F if the statement is false.
_______51. Fungal leaf spots and stem rots are characterized by dry texture, concentric
rings, discoloration and fruiting structures.
_______52. Bacterial disease symptoms include a slimy texture, fishy or rotten odor, and
leaf spots that appear to run in irregular patterns on the leaf.
_______53. Sudden decline of a tree is usually caused by a nonliving factor such as toxic
chemicals, or drastic climate changes.
_______54. When conifer needles die and the damage has a uniform pattern, it usually
indicates that the problem was caused by living organisms such as fungi or
insects.
_______55. The first step in diagnosing a plant disease is correctly identifying the plant,
and then comparing the ‘sick’ plant with a healthy or normal plant to
determine whether a real problem exists.
_______56. Pathogens rarely infect 100% of their host plants at one time; instead, the
damage usually progresses with time as the pathogens multiply and spread
through the plant.
_______57. Signs are the modified appearance of an affected plant; for example, necrotic
tissue, chlorosis, cankers or galls.
_______58. Viruses commandeer a host plant’s cell to manufacture viruses identical to
themselves, so the plant cell is unable to function and grow normally.
_______59. Root nematodes are microscopic roundworms that cause moisture and
nutrient stress symptoms and general stunting of plants.
_______60. Victoria blight of oats attacks varieties of oats that were bred to be resistant
to crown rust.
_______61. Tomatoes that are resistant to Pseudomonas syringae pv. tomato, which
causes bacterial speck disease, have a protein that recognizes and locks onto
a protein produced by the bacterium, and their interaction alerts the rest of
the plant’s defense mechanisms.
9
Multiple choice questions. Please read each question carefully then place the letter of the
answer that best completes the statement in the blank beside the question.
_______62. Tomatoes grown using a legume cover crop as fertilizer had better disease
resistance than tomatoes grown on black polyethylene mulch with chemical
fertilizer. Which of the following statements are true?
A.
Scientists discovered that at least 10 genes in the tomatoes’ leaves
were turned on longer (“over-expressed”), which allowed them to live
longer than tomatoes grown on the plastic mulch.
B.
The cover crop allowed the tomato root system to produce increased
levels of cytokinins, a class of plant hormones that delay senescence.
C.
D.
E.
The resistant tomato plants had many more roots than tomatoes grown
under the traditional method of black plastic mulch with chemical
fertilizer.
Answers A and B are both true.
Answers A and C are both true.
_______63. Scientists are trying to cross soybeans with Glycine tomentella, a distant
cousin of soybeans that is resistant to several important diseases, to increase
genetic diversity of soybeans. G. tomentella is native to
A. Africa.
B. Australia.
C. Japan.
D. Netherlands.
E. United States.
_______64. Ug99, a new stem rust fungus first seen in Uganda in 1999, causes stem rust in
wheat. Which of the following statements about Ug99 is true?
A. It can infect crops within just a few hours, and can cause 100% crop loss.
B. It is resistant to the three major anti-rust genes used to protect nearly all
the world’s wheat.
C. It is vectored by aphids.
D. Answers A and B are both true.
E. Answers B and C are both true.
_______65. What is the name of the plant, resistant to root-knot nematodes, that gets its
resistance from a gene obtained from a resistant pimiento pepper?
A. Charleston Belle pepper.
B. Double Shield tomato.
C. Keystone squash.
D. Nemo-Be-Gone melon.
E. Norton grape.
10
AGH 483
Exam 2
10 November 2009
50-point exam; each question worth ½ point
Patrick Byers—Fireblight
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
1.
The active ingredient in bactericides used to control fireblight is
A.
Aluminum.
B.
Copper.
C.
Iron.
D.
Mercury.
E. Silver.
2.
Fireblight is caused by a
A.
Bacterium.
B.
Fungus.
C.
Mollicute.
D.
Nematode.
E. Virus.
3.
Which of the following statements about fireblight is true?
A.
Initial infections begin on young, fully-expanded leaves.
B.
Fireblight pathogens cannot survive in plant vascular tissue.
C.
Canker blight is usually associated with damage from hail, high wind or frost.
D.
Cool and dry weather favors the development of fireblight.
E. None of the above is true.
4.
Fireblight occurs in species of
A.
Apples.
B.
Pears.
C.
Grapes.
D.
Answers A and B are both true.
E. All of the above are true.
5.
Which of these is a method to control fireblight?
A.
Reduce fertilizer applications.
B.
Increase fertilizer applications.
C.
Remove cankers when the plants are dormant.
D.
Answers A and C are true.
E. Answers B and C are true.
11
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
6.
Since most of the pathogens that cause fireblight are resistant to the antibiotics used to treat the
disease, growers of susceptible plants often use bacterial antagonists as biological controls.
7.
Fireblight is caused by the pathogen Pseudomonas syringae.
8.
Fireblight can be vectored by insects or rain.
9.
Fireblight evolved in North America and then spread to other continents.
10. The pathogen that causes fireblight overwinters in cankers that ooze in the spring.
11. Harpins are proteins produced by trees to interfere with the fireblight pathogen’s attack
mechanisms.
12. Ooze is a mixture of bacteria and polysaccharides.
13. There are no cultivars resistant to fireblight but researchers continue to try to develop them.
14. Penicillium and tetracycline are antibiotics used to control fireblight.
Late Blight of Potato and the Irish Potato Famine
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
15. Late blight of potato is caused by
A.
Agrobacterium radiobacter.
B.
Agrobacterium tumefaciens.
C.
Phytophthora infestans.
D.
Phytophthora ramorum.
E. Phytophthora syringae.
16. Potatoes are native to
A.
Africa.
B.
China or Southeastern Asia.
C.
Eastern Europe.
D.
North America.
E. South America.
17. The Irish Potato Famine occurred in the
A.
Mid-16th century.
B.
Mid-17th century.
C.
Mid-18th century.
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D.
Mid-19th century.
E. Mid-20th century.
18. The scientist who discovered the cause of Late Blight of Potato and is considered the ‘father’ of
plant pathology was
A.
Anton deBary.
B.
M.A. Farlow.
C.
Robert Koch.
D.
Democritus.
E. Louis Pasteur.
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
19. The epidemic triggered mass starvation, with around 1 million Irish people dying and 1 to 2
million emigrating to North America and Australia.
20. Late blight of potato spreads more rapidly during conditions of high moisture and warm
temperatures.
21. Sexual reproduction of the Late Blight pathogen requires two individuals of different mating
types.
22. The initial symptoms of new infection occur on the potato tubers.
23. One of the best management strategies against Late Blight is to bury diseased tubers at least six
inches beneath the soil.
24. The pathogen that causes Late Blight can produce both asexual and sexual spores.
Chapter 7
Environmental Effects on the Development of Plant Disease
13
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
25. The most rapid disease development usually occurs when the temperature is
A.
Above 85° F.
B.
Below optimum for both the pathogen and the plant, but favors the pathogen’s growth
more than the growth of the plant
C.
Optimum for the development of both the host plant and the pathogen.
D.
Optimum for the development of the host plant but is above or below the optimum for the
development of the pathogen.
E. Optimum for the development of the pathogen but is above or below the optimum for the
development of the host plant.
26. If both the pathogen and the crop plant grow best at a cool temperature but the disease is most
severe when the weather is warm, the disease probably occurs because the temperature is
A.
Below optimum for both the pathogen and the plant, but favors the pathogen’s growth
more than the growth of the plant.
B.
Optimum for the development of both the host plant and the pathogen.
C.
Optimum for the development of the host plant but is below the optimum for the
development of the pathogen.
D.
Optimum for the development of the pathogen but is above the optimum for the
development of the host plant.
E. All of the above are true.
27. Which of the following statements about pathogenic bacteria is true?
A.
Bacteria reproduce inside plant tissues at a slower rate during wet weather.
B.
High moisture or high relative humidity inhibits most bacteria.
C.
The ooze allows bacteria to move to the plant surface and then infect new plants.
D.
The ooze is a substance produced by plants to try to kill the bacteria.
E. All of the above are true.
28. Application of a potassium fertilizer may make a plant more disease resistant by
A.
Acting as a toxin to some pathogens.
B.
Hastening maturity of the crop.
C.
Making the plant less succulent.
D.
Promoting wound healing.
E. All of the above are true.
29. Wind increases the spread of pathogens by
A.
Causing wounds on plants.
B.
Carrying insect vectors to plants.
C.
Drying out the wet surface of the plants.
D.
Answers A and B are true.
E. All of the above are true.
14
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
30. Soil pH usually affects pathogens more than plants.
31. While the effect of temperature on viruses is unpredictable, generally viruses that cause mosaic or
ringspot symptoms are worse in the spring than at other times of the year.
32. Turgor pressure is the driving force behind growth of a plant.
33. Most disease epidemics are caused by pathogens spread directly by wind or indirectly by insect
vectors carried long distances by the wind.
34. Etiolation is a disorder in plants caused by mineral toxicity.
35. Tree wrap or paint is not recommended as a method to prevent sunscald injury because the wrap
or paint clogs the bark’s lenticels.
36. Soil pathogens are often more virulent when the soil is nearly saturated.
Chapter 8
Plant Disease Epidemiology
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
37. Which factor below does not favor the development of epidemics?
A.
Dense plantings.
B.
No-Till culture.
C.
Poor sanitation.
D.
Resistant varieties.
E. Wet weather.
38. The economic threshold is when
A.
Fungicides go on sale and a grower buys large quantities of them to have plenty for the
future.
B.
Growers switch to resistant varieties so they do not have to buy pesticides.
C.
It is more profitable to grow the pathogens to sell to researchers than to grow the crop.
D.
The cost of controlling a disease is higher than the loss in yield or quality if the disease is
not controlled.
E. The cost of controlling a disease is less than the loss in yield or quality if the disease is not
controlled.
15
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
39. Favorable temperatures and moisture allow polycyclic pathogens to complete several infections
cycles per year.
40. Epidemics caused by soil-borne pathogens are usually slow-spreading but severe.
41. Polycyclic pathogens have more than one life cycle per season.
42. Cedar-apple rust is an example of a diseased caused by a fungus with a polyetic life cycle.
43. Non-optimum temperatures (for the plants) tend to decrease horizontal resistance but may totally
eliminate vertical resistance.
44. Dutch Elm Disease is caused by an exotic pathogen (the pathogen originated in another country).
45. Plant quarantine measures are not always effective at preventing the introduction of exotic
pathogens to other countries.
46. Asian Soybean Rust is vectored by aphids.
Chapter 9
Control of Plant Diseases
Matching. Carefully read each description, and then match it with the phrase that best matches
the description. Indicate your answers on the scantron sheet.
A.
B.
Exclude pathogen from host
Eradicate or reduce inoculum
C.
D.
47. Antibiotics.
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Immunize or improve resistance
Use direct protection methods
48. Quarantines and inspections.
49. Evasion or avoidance.
50. Eliminate plants that are alternate hosts for a certain pathogen.
51. Fungicides.
52. Plant defense activators.
53. Produce seed or tubers where the climate is unsuitable for pathogens.
54. Proper fertilization.
55. Reflective sheets of mulch.
56. Removing infected fruit or other debris.
57. Spraying antagonistic microbes on oranges after harvest.
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
58. Plants can sometimes be protected from infection by a pathogen by coating the plant surface with
a protective material.
59. Crop rotation is usually less successful if the pathogen is able to survive in a long-lived dormant
state or can survive as a saprophyte until it detects a suitable host plant.
60. The use of resistant varieties is among the least expensive, easiest, safest and most effective
methods to control plant diseases.
61. Suppressive soils prevent the development of soilborne pathogens that cause severe diseases.
62. Antagonistic soils contain higher than normal numbers of plant pathogens.
63. Trap plants attract pathogens or the insects that vector pathogens.
17
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
64. This U.S. regulation was designed to prohibit or restrict entry of plants, plant products, soil or
other materials that might carry plant pathogens.
A.
APHIS Import Authorization System of 1912.
B.
HUD Plant Control Act of 1912.
C.
Plant Germplasm Quarantine and Indexing Program of 1912.
D.
Plant Quarantine Act of 1912.
E. USDA Plant Disease Control Act of 1912.
65. Which of these measures is NOT a major goal of an integrated plant disease control program?
A.
Delaying the onset of a disease.
B.
Eliminating or reducing the amount of initial inoculum.
C.
Increasing the host’s resistance.
D.
Preventing a disease from occurring.
E. Speeding up the secondary disease cycles.
66. The main goal of any disease control program is to eliminate or reduce
A.
All signs of pathogens.
B.
Dehydration.
C.
Moisture on leaves.
D.
One of the factors in the disease triangle.
E. Stress to the plant.
67. Pathogens introduced into a new area may cause a catastrophe because
A.
None of the pathogen’s natural enemies may exist in the area.
B.
Plants in the area had no opportunity to develop resistance against the pathogen.
C.
The pathogen may quickly cause a disease epidemic.
D.
All of the above are true.
E. None of the above is true.
Chapter 10: Environmental Factors that Cause Disease
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
68. How do high temperatures damage plants?
A.
Damage membranes.
B.
Denature proteins.
C.
Inactivate or accelerate enzyme systems.
D.
Scorch leaves.
E. All of the above are true.
69. How do chilling temperatures damage plants?
A.
Damage cell membranes.
B.
Formation of razor-sharp ice crystals that pierce cells and tissues.
18
C.
Inactivate or accelerate enzyme systems.
D.
Kill beneficial insects living on the plants.
E. All of the above are true.
70. Effects on plants of excessive soil moisture include
A.
Below normal levels of oxygen trapped in soil air pockets.
B.
Damage from toxins produced by anaerobic microbes.
C.
Decreased water tension in the xylem.
D.
Slower internode elongation.
E. All of the above are true.
71. Which of the following is NOT true?
A.
Wilt can be a symptom of excessively high soil moisture.
B.
Low humidity is a common problem with houseplants during the winter.
C.
Light intensity affects the amount of damage caused by air pollution.
D.
High relative humidity can increase transpiration and result in increased uptake of
nutrients.
E. Toxic levels of minerals in the soil usually cause direct damage to plant cells.
72. Which of the following statements about the essential mineral potassium is true?
A.
Hastens maturity and senescence in some crops.
B.
Increases likelihood that plants will suffer frost injury.
C.
Is a major component of plant cell walls.
D.
Promotes wound healing.
E.
All of the above are true.
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
73. Humans can cause plant abiotic diseases.
74. Tapered trunks will withstand less wind stress than those that have little or no taper.
75. Low temperatures damage more crops than high temperatures, but high temperatures can cause
faster, greater damage than low temperatures.
76. Ozone, incomplete fuel combustion, and ethylene from harvested fruits can cause damage to
plants.
77. An example of a physiogenic response is when a plant gets spots on its leaves after being irrigated
with cold water.
78. Gases from harvested fruits can be a source of air pollution that could damage or kill plants.
79. Toxic levels of minerals in the soil may cause a deficiency of essential elements such as calcium
or iron.
19
Brie Menjoulet: Soybean Diseases
Multiple choice questions. Please read each question carefully then mark the letter of the answer
that best completes the statement on the scantron sheet.
80. When plants in the Mustard family are grown as a cover crop and then tilled under, as
they decay they release an exudate that is a cyanide-type chemical (isothiocyanate).
This chemical is antagonistic to fungal pathogens. Guest speaker Brie Menjoulet
referred to this kind of crop as a/an
A.
Antisporulate.
B.
Biofumigant.
C.
Circumvention.
D.
Mycotoxin.
E. Myrosinase.
81. This soybean disease is generally associated with warm weather, not the cool and moist
conditions that contribute to the development of most soybean diseases.
A.
Bacterial blight.
B.
Cercospora leaf blight.
C.
Pythium seed decay and damping-off.
D.
Fusarium seedling blight.
E. Sudden death syndrome.
82. This disease of soybeans is caused by a bacterium, not a fungus.
A.
Bacterial blight.
B.
Frog-eye leaf spot.
C.
Fusarium root rot.
D.
Pythium seed decay.
E. Sudden death syndrome.
83. Spores of the fungi that cause rusts and mildews are spread primarily by
A.
Improper tillage.
B.
Infected seed.
C.
Insect vectors.
D.
Water splashing.
E. Wind.
20
Matching. Carefully read each description, and then match it with the phrase that best matches
the description. Indicate your answers on the scantron sheet.
A. Fusarium root rot
B. Fusarium seedling blight
C. Phomopsis seedling blight
D. Phytophthora seedling blight
E. Sudden death syndrome
84. Associated with high maintenance, high irrigation and high fertilizer use.
85. Causes the taproot to break or pull away.
86. Seed coat may remain on cotyledons of affected plants.
87. Slicing open the tap root reveals the white, fuzzy growth of the fungal mycelium.
88. Starts with interveinal yellowing of the leaves followed by browning and lesions.
Matching. Carefully read each description, and then match it with the phrase that best matches
the description. Indicate your answers on the scantron sheet.
A.
B.
C.
Cercospora leaf blight
Downy mildew
Frog-eye leaf spot
D.
E.
Septoria brown spot
Soybean mosaic virus
89. Causes purple seed stain.
90. Causes spots or blotches on the upper surface of young leaves, and as the fungus develops on the
lower side of the leaf, a purple-gray fuzz is visible.
91. Leaves have small round gray spots with reddish-brown borders.
92. Leaves have yellow mottling or mosaic patterns, puckering and distortion.
21
True/false questions. Please read each statement carefully to decide if it is true or false, and then
mark the correct answer on the scantron sheet. On a scantron, True = A and False = B.
93. Phytophthora seedling blight kills the seed in the ground.
94. Weather conditions play a vital role in the development of soybean diseases.
95. In soybean growth stages, V stands for vegetative and R stands for reproductive.
96. Most soybean diseases are caused by bacteria.
97. Soybean mosaic virus is vectored by leafhoppers.
98. Sudden Death Syndrome is a problem in years of drought.
99. Once Sudden Death Syndrome symptoms occur, control actions can be taken.
100. Phomopsis seedling blight can survive on seed.
101. Most soybean pathogens can survive in crop residue.
102. Oospores are dormant fungi in the soil.
22
AGH 483
Exam 3
15 December 2009
50-point exam; each question is worth ½ point
Chapter 11 Plant Diseases Caused by Fungi
Multiple choice questions. Please read each question carefully then write the letter of the answer
that best completes the statement on the line next to the question.
______1.
Fungal cell walls are composed mostly of
A.
Cellulose.
B.
Chitin.
C.
Lignin.
D.
Lipids.
E.
Opines.
______2.
This disease could be controlled with a single fungicide application early in the spring.
A.
Alternaria Leaf Spot.
B.
Cedar-Apple Rust.
C.
Fusarium Wilt.
D.
Sooty Mold.
E.
Taphrina Leaf Curl.
______3.
This fungal genus is responsible for Ergot diseases.
A.
Alternaria.
B.
Claviceps.
C.
Erwinia.
D.
Fusarium.
E.
Taphrina.
______4.
These are among the fungi that cause wilt diseases.
A.
Alternaria.
B.
Erwinia.
C.
Taphrina.
D.
Verticillium.
E.
Answers C and D are both true.
______5.
This disease is known as gray mold.
A.
Alternaria Leaf Spot.
B.
Anthracnose.
C.
Botrytis.
D.
Fusarium Wilt.
E.
Rhizopus Soft Rot.
______6.
Fungi responsible for this disease secrete pectinase and cellulase.
A.
Alternaria Leaf Spot.
B.
Botrytis Blight.
23
C.
D.
E.
Cedar-Apple Rust.
Rhizopus Soft Rot.
Taphrina Leaf Curl.
______7.
The filamentous body of a fungus is called
A.
Apothecium.
B.
Conidium.
C.
Haustorium.
D.
Mycelium.
E.
Sporangium.
______8.
The feeding structure a fungus sends into plant cells is called
A.
Apothecium.
B.
Conidium.
C.
Haustorium.
D.
Mycelium.
E.
Sporangium.
______9.
About 75% of all fungi are in this group.
A.
Ascomycetes.
B.
Basidiomycetes.
C.
Chytridiomycetes.
D.
Deuteromycetes.
E.
Zygomycetes.
______10.
Young women killed during the Salem Witch Trials had probably consumed
A.
Corn smut.
B.
Ergot-tainted rye bread.
C.
Green beans infected with Asian Soybean Rust.
D.
INA bacteria.
E.
Leprechaun cursed mushrooms.
______11.
The resting or overwintering stage of a fungus, usually characterized by a hard mass, is
known as a/an
A.
Anamorph.
B.
Conidiophore.
C.
Sclerotium.
D.
Teleomorph.
E.
Answers A and D are both true.
______12.
This ascomycete produces an aflatoxin.
A.
Apothecium niger.
B.
Aspergillus flavus.
C.
Basiomycetes zygomycetes.
D.
Candida albicans.
E.
Ectomycorrhizae.
______13.
Which of these groups are no longer classified as true fungi?
A.
Ascomycetes.
B.
Basiomycetes.
C.
Chytridiomycetes.
24
D.
E.
Oomycetes.
Zygomycetes.
True or false. Read the question carefully, and then place a T in the space next to the statement if
it is true. Place an F in the space next to the statement if it is false. On a scantron, True = A and
False = B.
______14.
Cedar apple rust is an example of a disease caused by a polycyclic pathogen.
______15.
Corn smut, caused by a fungus called Ustilago maydis, damages plants and reduces yields
by forming galls on the ears.
______16.
Soil fungi typically have a wide host range.
______17.
Fungi almost always produce spore-bearing structures on or near the plant’s epidermis so
that the germinating spores will be easily dispersed.
______18.
Fungal spores are usually disseminated by water.
______19.
The sexual life stage of a fungus if referred to as the teleomorph.
______20.
Snow mold is one of the most devastating diseases of turfgrasses.
______21.
Sooty mold is a weak pathogen that feeds off of honeydew secreted by plant insect pests.
______22.
Powdery mildew can be wiped off of the surface of a plant, making it easy to control
without use of a fungicide.
______23.
The club and mushroom fungi are in the basidiomycete phylum.
25
Chapter 12
Plant Diseases Caused by Bacteria
Multiple choice questions. Please read each question carefully then place the letter of the answer
that best completes the statement in the blank.
______24.
Which of the following is NOT a genus of pathogenic bacteria?
A.
Agrobacterium.
B.
Clavibacter.
C.
Pseudomonas.
D.
Rhizobium.
E.
Xanthomonas.
______25.
The most common symptom caused by plant bacterial diseases is
A.
Crown or root galls.
B.
Excessive yield.
C.
Leaf spots.
D.
Soft rots.
E.
Vascular wilts.
______26.
Soft rot pathogens typically use which type of chemical weapon to obtain nutrition from
harvested fruits and vegetables?
A.
Arsenic.
B.
Enzymes.
C.
Growth regulators.
D.
Polysaccharides.
E.
Toxins.
______27.
Bacterial cell walls are usually surrounded by a viscous, gummy material called
A.
Cytoplasm.
B.
Mollicute.
C.
Oozism.
D.
Sclerotium.
E.
Slime layer.
______28.
Pierce’s Disease of Grapes is caused by this xylem-inhabiting bacterium which is
transmitted by grafting and leafhoppers.
A.
Bacillis bacteriodus.
B.
Clostridium pestis.
C.
Helicobacter pylori.
D.
Mycobacterium tuberculosis.
E.
Xylella fastidiosa.
______29.
The pathogen responsible for Fire Blight on apples, crabapples and other members of the
Malus family is
A.
Erwinia amylovora.
B.
Fusarium oxysporum.
C.
Phytophthora infestans.
D.
Rhizobium spp.
E.
Ustilago maydis.
This genus of bacteria is filamentous rather than being rod-shaped.
26
______30.
A.
B.
C.
D.
E.
Agrobacterium.
Erwinia.
Fusarium.
Streptomyces.
Ustilago.
______31.
This group of enzymes, produced by some bacterial species, degrades proteins.
A.
Amylase.
B.
Carboxylase.
C.
Lipase.
D.
Pectinase.
E.
Proteases.
______32.
This compound has historically been effective as a bactericide.
A.
Copper.
B.
Magnesium.
C.
Nitrogen.
D.
Sodium.
E.
Sugar.
______33.
This species is antagonistic to Agrobacterium tumefaciens.
A.
Agrobacterium radiobacter.
B.
Phaseolus syringae pv. phaseolicola.
C.
Pseudomonas rubrilineans.
D.
Rhizobacter agrobacterium.
E.
Rhizobium bacteroides.
True/false questions. Please read each statement carefully then on the line next to the statement
place a T if the statement is true or an F if the statement is false. On a scantron, True = A and
False = B.
______34.
Bacteria produce appressorium and penetration pegs to penetrate plant tissues.
______35.
Around 3,500 species of bacteria can cause diseases in plants.
______36.
The mere exponential multiplication of bacteria inside a plant can cause crowding of cells
and tissues, causing a collapse and rupturing of plant cells.
______37.
Pseudomonas and Xanthomonas are the primary genera of bacteria that cause spots and
blights of plant leaves, stems and fruits.
______38.
Bacteria can ooze out of plant wounds or natural openings during conditions of high
humidity, and be rain-splashed or wind-born to cause infections in new plants or new areas
on the same plant.
______39.
Bacteria that cause vascular wilts usually attack only woody species.
27
______40.
Bacterial streaming is the phenomena seen when the pathogens ooze out of plant stomata.
______41.
The endosymbiotic theory states that mitochondria and chloroplasts evolved from ancient
bacterial species.
______42.
Soft rot bacteria such as Erwinia and Pseudomonas produce enzymes that dissolve the
middle lamella in fleshy plant tissues.
______43.
INA (Ice Nucleation Active) bacteria are involved in causing freeze damage to plants.
______44.
Spiroplasmas and phytoplasmas lack a cell wall.
Chapter 13 Plant Diseases Caused by Parasitic Higher Plants
True/false questions. Please read each statement carefully then on the line next to the statement
place a T if the statement is true or an F if the statement is false. On a scantron, True = A and
False = B.
______45.
The best control method for dodder is the use of resistant crop plants.
______46.
Dodder finds potential hosts by detecting volatile chemicals emitted by the plants.
______47.
Dodder is typically disseminated by rain droplets that splash pieces of it onto the host
foliage.
______48.
Once dodder comes in contact with a susceptible plant, it sends haustoria inside the leaf or
stem to absorb food and water.
______49.
Dodder is a non-obligate parasite, able to produce a root system and feed off of plant
debris and other organic matter in the soil until a suitable host grows nearby.
______50.
Plants infected with dodder often are stunted or produce low yields.
______51.
Two varieties of dodder conduct photosynthesis, and they are typically a dark green color.
______52.
Parasitic higher plants produce flowers and seed.
______53.
Dodder may vector viruses.
______54.
True mistletoe are dioecious, producing both male and female plants, and the female plants
are the ones that have berries.
______55.
Mistletoe is spread by both active and passive dissemination.
28
______56.
Mistletoe plants produce sticky seeds.
______57.
Mistletoe seeds produce a radicle and longitudinal haustorial sinkers that pierce the plant
and absorb nutrients from the phloem.
______58.
Mistletoe usually produces an allelopathic substance that inhibits secondary pathogens
from attacking the host plant.
______59.
Dwarf Mistletoe is found on conifers, while true or leafy mistletoe infects hardwood and
fruit trees.
Chapter 15 Plant Diseases Caused by Nematodes
Multiple choice questions. Please read each question carefully then write the letter of the answer
that best completes the statement on the line next to the question.
______63.
Nematodes are large enough pathogens to employ a direct attack against host plants. Their
attack includes which of the following weapons?
A.
Mouth suction with as many as six lips to adhere to the plant.
B.
Needlelike stylet that thrusts back and forth to puncture the plant
C.
Toxins injected into plants to disintegrate tissue.
D.
Answers B and C are true.
E.
All of the above are true.
______60.
Which of the following statements about nematodes is NOT correct?
A.
A life cycle can be as rapid as 2 to 4 weeks when conditions are favorable.
B.
Occur mostly in the top 15 to 30 cm of soil.
C.
Nematodes are wormlike but are not true worms.
D.
Nematodes don’t really cause significant crop losses since most nematodes are
beneficial species.
E.
All of the statements are incorrect.
______61.
Which of these statements about nematodes is NOT true?
A.
Digestive system consisting of hollow tube from mouth to anus.
B.
Many offspring.
C.
No legs or other appendages.
D.
Segmented worm.
E.
Transparent body.
Which of these are symptoms of plants infected by nematodes?
A.
Chlorosis.
B.
Excessive branching.
C.
Lower yield.
D.
Nutrient deficiencies.
______62.
29
E.
______63.
All of the above are true.
Which of these is NOT a method to control nematode diseases?
A.
Antagonistic bacteria.
B.
Antagonistic fungi.
C.
Heavy nitrogen applications to the soil.
D.
Nematicides.
E.
Resistant varieties.
True/false questions. Please read each statement carefully then on the line next to the statement
place a T if the statement is true or an F if the statement is false. On a scantron, True = A and
False = B.
______64.
Plant roots may release ‘hatching factor’ chemicals into the soil that stimulate hatching of
eggs of certain nematode species; however, most nematode eggs hatch freely in water
without any special stimulus.
______65.
Nematodes are able to travel through the soil and move faster when the soil pores are
waterlogged than when lined with only a thin film of water.
______66.
Some nematode species attack stems or leaf surfaces, rather than roots.
______67.
Nematodes vector some viruses including tomato ringspot.
______68.
Female nematodes can produce fertile eggs after mating with a male or in the absence of a
male.
______69.
The eggs of some species of nematodes can remain dormant in the soil for years while
waiting for a susceptible host plant.
______70.
While nematodes can attack most deciduous plant species, conifers are fortunately immune
to nematodes.
______71.
Pine wilt nematodes are vectored by fungi.
______72.
Plants ordinarily resistant to fungal diseases such as Fusarium Wilt are more likely to
become infected by those fungi if they are infected by nematodes.
______73.
Some nematodes are used as biological controls against other plant pests.
Dr. Wenping Qiu—Diagnosis of Plant Viral Diseases
Multiple choice questions. Please read each question carefully then write the letter of the answer
that best completes the statement on the line next to the question.
30
______74.
A unique characteristic of the Tomato Spotted Wilt Virus is that the viral particle
A.
Can live on leaf surfaces for extended periods of time.
B.
Causes bronzing on leaves of grapes that it infects.
C.
Forms a symbiotic relationship with host plants.
D.
Has a very narrow host range, unlike most viruses.
E.
Has an outer membrane.
______75.
Tomato Spotted Wilt Virus, which causes diseases on more than 500 species of plants, is
vectored by this insect, and can actually replicate inside the vector’s body during certain life
stages of the insect.
A.
Aphid.
B.
Caterpillar.
C.
Mealybug.
D.
Spider mite.
E.
Thrips.
______76.
This plant is used as an indicator plant for bio-indexing to detect viruses.
A.
Grape.
B.
Lambsquarters.
C.
Mum.
D.
Spathiphyllum.
E.
Tobacco.
______77.
This viral disease is vectored by mealybugs.
A.
Berry Yellows.
B.
Grape Leaf Roll Associated Virus.
C.
Marshmallow Blight.
D.
Muskmelon Bushy Stunt Virus.
E.
Tomato Spotted Wilt Virus.
______78.
A protein-based assay to detect or identify viruses is
A.
Berry Gradient Assay (BGA).
B.
Polymerase Chain Reaction (PCR).
C.
Enzyme-Linked Immunosorbant Assay (ELISA).
D.
Replicate Action Detection (RAD).
E.
Systemic Mosaic Infection Syndrome (SMIS).
______79.
A nucleic acid-based assay to detect or identify viruses is
A.
Berry Gradient Assay (BGA).
B.
Polymerase Chain Reaction (PCR).
C.
ELISA.
D.
Replicate Action Detection (RAD).
E.
Systemic Mosaic Infection Syndrome (SMIS).
Scientists mapping the genome of the Tomato Bushy Stunt
Virus found genes coding for replicase proteins (RP), coat proteins (CP), unknown protein
(pX) and the virus genomic RNA, as well as MP proteins. MP is an abbreviation for
A.
Mealybug vector proteins.
B.
Membrane protease.
C.
Mitochondria pathway proteins.
31
______80.
D.
E.
Movement proteins.
Muscular proteins.
True/false questions. Please read each statement carefully then on the line next to the statement
place a T if the statement is true or an F if the statement is false. On a scantron, True = A and
False = B.
______81.
Antibodies are a type of protein. They are produced by a mammal’s immune system in
response to foreign substances that may be a threat to the body.
______82.
Sometimes a plant is suspected of having a viral infection but has no symptoms. Using sap
from the suspicious plant, scientists can inoculate plants that are susceptible to most
viruses (and readily show symptoms when they become infected). This procedure is known
as bio-indexing.
Dr. Laszlo Kovacs—Crown Gall Disease and Agrobacterium tumefaciens
True/false questions. Please read each statement carefully then mark the correct answer on the
scantron sheet. On a scantron, True = A and False = B.
______83.
The virulence region of Agrobacterium tumefaciens’ chromosomes can be removed and
replaced with other genes.
______84.
Galls formed when a plant is infected with Crown Gall do not have an epidermis, making it
easy for other microbes to invade the gall tissue.
______85.
Galls on a plant infected with Crown Gall usually develop from transformed cambial cells.
______86.
Crown gall is usually worse in tropical or subtropical regions than in temperate areas where
the ground freezes in winter.
______87.
A. tumefaciens is related to Rhizobium bacteria, and both of the genera evolved to have
very intimate relationships with eukaryotic cells.
Multiple choice questions. Please read each question carefully and then mark the correct answer
on the scantron sheet.
______88.
A plasmid is
A. A mobile chromosome.
B. Used to transfer resistance genes from one bacterium to another.
32
C.
D.
E.
Important in genetic engineering.
All of the above are true.
None of the above is true.
______89.
A. tumefaciens forces plant cells to produce an unusual compound that can be used as
food if an organism possesses certain enzymes to break down the compound. Only the
same bacterial strain that induced the plant to produce the compound possesses those
enzymes. This compound is
A. Agrocin 84.
B. Cytokinins.
C. ELISA.
D. Opines.
E. None of the above is true.
______90.
This was the first successful biological control organism used to prevent a plant disease.
A.
Agrobacterium radiobacter.
B.
Agrobacterium tumefaciens.
C.
TSWV bio-indexing.
D.
Xylella fastidiosa.
E.
None of the above is true.
______91.
This condition is required for Agrobacterium tumefaciens to infect a plant.
A.
Drought.
B.
Soil temperatures between 25° and 65° F.
C.
Wounding/healing.
D.
All of the above are true.
E.
None of the above is true.
______92.
A. tumefaciens genes force plant cells to produce these plant hormones.
A.
Abscisic acid and ethylene.
B.
Auxin and cytokinin.
C.
Auxin and gibberellin.
D.
Cytokinin and ethylene.
E.
Gibberellin and testosterone.
Casey Jo Kellner—Missouri Department of Agriculture Plant Health Inspector
Multiple choice questions. Please read each question carefully then write the letter of the answer
that best completes the statement on the line next to the question.
33
______93.
Outbreaks of exotic diseases and insects are increasing while the Missouri Department of
Agriculture’s budget is shrinking (which means it is understaffed to take care of so many
pest threats). Casey Jo Kellner said that a major reason for the increase in exotic pests is
A.
Birds migrating from places where the pests originate.
B.
Global warming.
C.
Increased global trade using solid wood packing material.
D.
Travelers unknowingly bringing them into the United States while smuggling plants
or animals.
E.
All of the above are true.
______94.
Thousand Cankers Disease (TCD) is caused by this pathogen.
A.
Alternaria juglandis.
B.
Cryphonectria parasitica.
C.
Geosmithia morbida.
D.
Leotia lubrica.
E.
Ophiostoma novo-ulmi
______95.
The first documented case of TCD was in
A.
Arizona.
B.
California.
C.
Colorado.
D.
New Mexico.
E.
West Virginia.
True/false questions. Please read each statement carefully then mark the correct answer on the
scantron sheet. On a scantron, True = A and False = B.
______96.
The ‘Butthead’ theory of the spread of TCD states that the walnut twig beetle was on
firewood transported long distances by humans.
______97.
The ‘Big Bang’ theory of the spread of TCD states that the walnut twig beetle was carried
on wind currents caused by severe volcanic activity in the Pacific Ocean.
______98.
Thousand Cankers Disease (TCD) is an insect/bacterial complex.
______99.
TCD infects all Juglans species.
______100.
The walnut twig beetle is slightly larger than a penny in its adult phase.
______101.
The pathogen that causes TCD is an exotic (introduced from another country) pathogen.
______102.
Missouri has a substantial black walnut population, so the Missouri Agriculture Department
considers TCD as a threat to watch for.
34