AGH 483
Exam 1
4 Oct. 2004
33 points (1 bonus point is built into the exam)
Chapter 1 Introduction and Diagnosis of Disease
Multiple choice questions. Please read each question carefully then place the letter of
the answer that best completes the statement in the blank. Each question is worth ½
point.
______1.
Which of the following disease classification categories are considered the most
useful?
a.
Plant organ the disease affects.
b.
Symptoms the disease causes.
c.
Type of pathogen.
d.
Types of plants affected.
______2.
Plant pathology is the study and control of ______________________ that cause
disease.
A.
Abiotic and environmental factors.
B.
Biotic and abiotic factors.
C.
Pathogens and environmental factors.
D.
Answers b and c are true.
______3.
When trying to obtain a sample of living pathogens to place into culture, where on an
infected leaf are you most likely to find the pathogens?
A.
At the leaf tip.
B.
In the veins.
C.
Near the margins of the affected area.
D.
On the underside of the leaf.
______4.
Fungi that cause plant diseases are best identified by what characteristics?
A.
Constant presence of many fungi in the affected area.
B.
Fruiting structures.
C.
Length and morphology of hyphae.
D.
Structure of their mouth parts.
______5.
Diagnosis of a bacterial disease is based primarily on
A.
Symptoms of the disease.
B.
Constant presence of large numbers of bacteria in the affected area.
C.
Absence of any other pathogens.
D.
All of the above are true.
1
______6.
Diagnosis of a disease caused by viruses and viroids is based on
A.
Constant presence of large numbers of viruses in the affected area.
B.
Fruiting structures.
C.
Structure of their mouth parts.
D.
None of the above.
______7.
Diagnosis of an abiotic disease is based on the fact(s) that
A.
No pathogen can be found, cultured or transmitted.
B.
The abiotic pathogen causes similar diseases in other members of the same
plant species.
C.
The symptoms disappear when the plant is fertilized.
D.
You know the plant experienced unfavorable environmental conditions
recently.
______8.
This scientist in the late 1800s established a set of procedures to isolate and identify
the causative agent of a particular microbial disease.
A.
DeBary.
B.
Koch.
C.
Pasteur.
D.
Sars.
______9.
Which of the following disease categories are considered the most useful?
A.
Plant organ the disease affects.
B.
Symptoms the disease causes.
C.
Type of pathogen.
D.
Types of plants affected.
Short answer. Please read the question carefully then write the correct answers in the
spaces provided. ½ point
10.
Plant pathology is the study and control of ______________________ and
________________________ that cause diseases.
2
Chapter 2
Parasitism and Disease Development
Multiple choice questions. Please read each question carefully then circle the letter of
the answer that best completes the statement. Each question is worth ½ point.
_______1.
A pathogen is
A.
Microbe that causes disease.
B.
Organism that removes nutrients and water from its host.
C.
Parasite.
D.
All of the above.
_______2.
Symptoms (but not signs) of a disease include
A.
Galls produced by parasitic wasps.
B.
The powdery substance on lilac leaves infected with powdery mildew.
C.
Wilt.
D.
Both a and c are correct.
_______3.
All of the following are examples of prepenetration phenomena except:
A.
Entry into the plant by an insect-vectored virus.
B.
Germination of fungal spores.
C.
Growth of the germ tube after a fungal spore germinates.
D.
Hatching of nematode eggs.
_______4.
If a row of shrubs begin to show disease symptoms because the soil was flooded, this
is an example of
A.
Abiotic Disease Factors.
B.
Biotic Disease Factors.
C.
Symbiotic Disease Factors.
D.
None of the Above.
_______5.
The three components necessary for a plant disease to occur are
A.
Wind.
B.
Water.
C.
Spore or insect vector.
D.
None of the above.
Short answer. Please read the question carefully then write the correct answers in the
spaces provided. You must get all answers correct to receive credit for this problem. 1
point
6.
List the five stages of the disease cycle, in the correct order.
A. ________________________
D.
________________________
B.
________________________
E.
________________________
C.
________________________
3
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. Each
question is worth ½ point.
_______7. Inoculation = infection.
_______8. A pathogen can be defined as an organism that can cause disease.
_______9. Obligate parasites require a living host for growth and reproduction.
_______10. Viruses are nonobligate parasites.
_______11. Inoculation is the point in time when the pathogen comes into contact with the plant.
_______12. Viruses sometimes produce inoculum on the surface of plants.
_______13. Viruses are always spread by insect vectors.
_______14. Bacteria usually enter plants with the help of insect vectors.
_______15. Fungi and bacteria may overwinter on the surface of seeds or tubers.
4
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. Each question is worth ½
point.
_______1.
Some pathogens release a certain type of enzyme to break down the ‘cement’ or
substance that holds cells together. This enzyme is
A.
Cellulase.
B.
Cutinase.
C.
Pectinase.
D.
Phenolics.
_______2.
Fungi and parasitic plants must adhere to the surface of a plant before penetrating the
surface. Methods of adhesion include
A.
Adhesion pad formed by a spore when it lands on the moist plant
surface.
B.
Intermolecular forces between the plant surface and the pathogen.
C.
Mucilage secreted by the fungus.
D.
All of the above are true.
_______3.
Microbial toxins are extremely poisonous substances that are effective in low
concentrations. The effect of the toxins includes
A.
Altering cell membrane permeability.
B.
Deactivating or inhibiting plant enzymes.
C.
Formation of an appressorium and penetration peg.
D.
Answers a and b are true.
_______4.
The pathogen responsible for Crown Gall is
A.
Agrobacterium tumefaciens.
B.
Erwinia amylovora.
C.
Phytophthora infestans.
D.
Ustilago maydis.
_______5.
The pathogen responsible for Late Blight of Potato is
A.
Agrobacterium tumefaciens.
B.
Erwinia amylovora.
C.
Phytophthora infestans.
D.
Ustilago maydis.
_______6.
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.
Ustilago maydis.
5
_______7.
Soft rot pathogens typically use which type of chemical weapon to obtain nutrition
from harvested fruits and vegetables?
A.
Enzymes.
B.
Growth regulators.
C.
Polysaccharides.
D.
Toxins.
_______8.
Fungi sometimes produce this enzyme to penetrate the plant surface.
A.
Cutinase.
B.
Gluconase.
C.
Pectinase.
D.
Polysaccharase.
_______9.
The structure in a plant that is the ‘cement’ holding cells together is called.
A.
Cutin.
B.
Lignin.
C.
Middle lamella.
D.
Plasdomesmata.
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. Each
question is worth ½ point.
_______10.
Fungi often secrete enzymes to soften the outer layers of a plant and make
for the penetration peg to break through the plant’s surface barrier.
_______11.
Nematodes penetrate a plant’s surface by secreting enzymes that degrade cutinase.
_______12.
Pathogens that cause crown gall affect the plant’s auxin levels.
_______13.
Polysaccharides are used by gall-forming pathogens to induce tumor formation.
_______14.
An adhesion pad helps fungal spores stick to the surface of a plant.
_______15.
A fungus’ threadlike structure that penetrates the surface of a plant is called an
appressorium.
_______16.
The fungi that cause white rot in woody species primarily use enzymes to degrade
lignin and other plant cell wall components.
6
it easier
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. Each question is worth ½
point.
_______1.
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.
_______2.
When a plant is under attack by pathogens, the plant’s xylem may become clogged
because of
A.
Growth of the pathogens.
B.
Secretions from the pathogens.
C.
Secretions from the plant in response to the pathogens.
D.
All of the above are true.
_______3.
Which of the following group of pathogens use a host cell’s nucleotides and
machinery to make its own DNA?
A.
Bacteria.
B.
Fungi.
C.
Nematodes.
D.
Viruses.
Short answer. Please read the question carefully then write the correct answer in the
space provided. 1 point
4.
Why would respiration of a plant tend to increase soon after it is attacked by a microbe?
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. Each
question is worth ½ point.
_______5.
The hypersensitive response is when a plant rapidly synthesizes substances to
reinforce cell walls to make penetration of the pathogen more difficult.
_______6.
Plant diseases caused by pathogens usually result in a decrease in respiration.
_______7.
Many bacterial diseases cause an increase in plant chlorophyll content.
7
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. ½ point each.
A.
B.
C.
D.
Preexisting plant structure
Induced plant structure
Preexisting biochemical defense
Induced biochemical defense
8
_______1.
Cork layer.
_______2.
Detoxification of pathogen toxins.
_______3.
Fungicides or other toxins released by the trichomes.
_______4.
Hypersensitive response. [choose one or the two answers that are possible]
_______5.
Sclerenchyma bundles in the stems.
_______6.
Superoxide radical.
_______7.
Stomatal regulation.
_______8.
Waxy surface.
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. Each question is
worth ½ point.
_______9.
Diseases typically cause an increase in transpiration.
_______10.
Phenolics inhibit enzymes that pathogens use to break down pectin.
_______11.
Saponins are chemicals produced by plants to break down fungal cell membranes.
_______12.
Lignin and suberin are phenolic compounds.
9
Chapter 6—Genetics of Plant Disease
Read each question carefully, then print the letter of the best answer on the line next to the
question. ½ point each.
_______1.
Plant diseases occur all over the world but are more common and more severe in
A.
Dry areas with cool, warm or tropical temperatures and long day lengths.
B.
Humid to wet areas with cool, warm or tropical temperatures.
C.
Latitudes north of 47.
D.
Latitudes south of 47.
_______2.
Pathogens with a similar morphology and phenotype are grouped into
A.
Clones.
B.
Genera and species.
C.
Isolates.
D.
Varieties or special forms.
_______3.
Individual members of a species of pathogen that attack only certain species of plants are
called
A.
Clones.
B.
Genera and species.
C.
Isolates.
D.
Varieties or special forms.
_______4.
There are over 200 races of Puccinia graminis tritici, the fungus that causes stem rust of
wheat. What is a race?
A.
Clones or offspring that reproduce asexually.
B.
Offspring of a biotype of pathogens that can suddenly attack a new species.
C.
Same variety but attack different varieties of plants within a species.
D.
Varieties or special forms.
_______5.
The soil-borne fungus that causes Fusarium Wilt is ubiquitous. What does ubiquitous
mean?
A.
Especially virulent.
B.
Found everywhere.
C.
Long-lived.
D.
Race or strain of a nonpathogenic species of fungus.
_______6.
Which of the following statements is NOT true about horizontal resistance?
A.
A lower level of resistance to any specific race of pathogen but effective against a
larger number of pathogens.
B.
Breeding requires insertion of many minor-effect genes.
C.
Confers incomplete but more durable protection.
D.
Most effective when incorporated into annual crops.
10
AGH 483
Exam 2
25 Oct. 2004
Chapter 7 Environmental Effects on the Development of Plant Disease
Read each question carefully, then print the letter of the best answer on the line next to the question.
½ point each.
______1.
Peas (Pisum sativum) are cool season plants that grow best at temperatures between
50° and 61° F, but can tolerate higher temperatures. Rhizoctonia Root Rot will
damage peas at relatively low soil temperatures (65° F) but is most aggressive under
warmer conditions (76° to 86° F). The rapid disease development at 76° to 86° F
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.
______2.
The optimum temperature for development of the disease black root rot of tobacco is
17 to 23C. The optimum temperature for the development of Thielaviopsis basicola,
the fungus that causes the disease, is 22 to 28C. The optimum temperature for
tobacco growth is 28 to 29C. Given these facts, which of the following statements are
true?
A. The pathogen and the host grow poorly at 17 to 23C.
B. The temperature is so detrimental to the growth of the plant that even a weakened
pathogen can escape the disease.
C. Both a and b are correct.
D. Neither a nor b is correct.
______3.
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. All of the above.
______4.
Wind increases the spread of pathogens by
A. Causing wounds on plants.
B. Drying out the wet surface of the plants.
C. Increasing relative humidity around the plant canopy.
D. All of the above.
11
______5.
For diseases that affect below-ground parts of a plant, which of the following
statements is NOT true?
A. Increased moisture may hamper a plant’s ability to defend itself.
B. Increased moisture seems to primarily favor the pathogen rather than the plant.
C. Severity of disease is greatest when the soil is somewhat dry.
D. All of the above.
______6.
These kinds of microbes usually result in local, slow-spreading diseases of
considerable severity.
A. Pathogens carried by airborne vectors.
B. Pathogens carried with seed, tubers or bulbs.
C. Pathogens spreading through the soil.
D. Pathogens whose spores are released into the air and spread by wind.
Read each question carefully, then write T (true) or F (false) on the line next to the question. ½ point
each.
______7.
Wind and rain can be a devastating combination in disease establishment because they
release spores and bacteria from infected tissue and carry them through the air to
deposit them on the wet surface of other plants.
______8.
Etiolation usually makes a plant more susceptible to obligate parasites.
______9.
Etiolation usually makes a plant more susceptible to viruses.
______10.
Unfavorable temperatures seem to weaken pathogens more than plants.
______11.
pH usually affects pathogens more than plants.
______12.
Plants that are overfertilized tend to stay succulent later into the growing season and
this makes them more likely to be attacked by pathogens.
______13.
Moisture increases the succulence of host plants and thus makes them more resistant
to most pathogens.
______14.
When phosphorus fertilization increases a plant’s resistance to disease, the phosphorus
is either making the plant healthier or allowing it to mature faster and thus escape
infection by pathogens that prefer succulent tissues.
12
Chapter 8 Plant Disease Epidemiology
Read each question carefully, then write T (true) or F (false) on the line next to the question. ½ point
each.
______15.
Cedar-apple rust is an example of a diseased caused by a fungus with a polycyclic life
cycle.
______16.
Favorable temperatures and moisture allow polycyclic pathogens to complete several
infections cycles per year.
______17.
An epidemic can be defined as any rapid increase of disease in a population of plants.
______18.
Some epidemics can be controlled weather or other natural conditions.
______19.
Most diseases that are likely to cause sudden and widespread epidemics are spread by
insect vectors.
______20.
Non-optimum temperatures tend to decrease horizontal resistance but may totally
eliminate vertical resistance.
______21.
Epidemics caused by soil-borne pathogens are usually slow-spreading but severe.
Read the question carefully, then print the letter of the best answer on the line next to the question. ½
point.
______22.
Which factor below does not favor the development of epidemics?
A. Dense plantings.
B. No-Till culture.
C. Poor sanitation.
D. Resistant varieties.
______23.
Which factor below does not favor the development of epidemics?
A. No-Till Culture.
B. Dense Plantings.
C. Resistant Varieties.
D. Poor Sanitation.
______24.
List the four components of the disease tetrahedron in the space below.
13
Chapter 9 Control of Plant Diseases
Read each question carefully, then print the letter of the correct answer on the line next to the
question. ½ point each.
______25.
The main goal of any disease control program is to eliminate or reduce
A. All signs of pathogens.
B. Stress to the plant.
C. Dehydration.
D. One of the factors in the disease triangle.
______26.
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.
______27.
The main goal of a quarantine is to
A. Eliminate the initial inoculum.
B. Immunize native plants against foreign pathogens.
C. Increase resistance of the host.
D. All of the above.
______28.
What is cross protection?
A. Plant susceptible varieties next to resistant varieties.
B. Protect a plant by infecting it with a mild strain of a severe pathogen.
C. Use two or more disease control methods at the same time.
D. Answers a and b.
______29.
What are some methods a grower can use to make conditions unfavorable for
pathogens?
A. Fertilize the plants monthly with large amounts of nitrogen.
B. Plant susceptible plants.
C. Space plants properly.
D. All of the above.
______30.
Economic threshold is
A. The maximum profit that can be earned with a healthy crop.
B. The maximum profit the USDA will allow for any given crop.
C. The point where the cost of controlling the disease is less than the cost of the
damage that would occur if no control measures were used.
D. The total cost of all cultural, mechanical and chemical control measures used in
one growing season.
14
True or false. 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. ½ point each.
______31.
Suppressive soils prevent the development of soilborne pathogens that cause severe
diseases.
______32.
Antagonistic soils contain higher than normal numbers of pathogens.
______33.
Trap plants are a type of biological weapon to repel pathogens or the insects that
vector pathogens.
______34.
Antagonistic plants repel pathogens or the insects that vector pathogens.
______35.
The use of resistant varieties is among the least expensive, easiest, safest and most
effective methods to control plant diseases.
______36.
As long as plants and pathogens can be kept away from one another, no disease will
develop.
15
Matching. Place the letter of the phrase that best matches the description in the space next to the
description. ½ point each.
A.
B.
C.
D.
Exclude the pathogen from the host
Eradicate or reduce inoculum
Immunize or improve resistance
Direct protection methods
16
______37.
Coat the plant epidermis with the clay mineral kaolinite (aluminum silicon
hydroxide).
______38.
Cross protection.
______39.
Cultural methods such as crop rotation.
______40.
Disinfect the warehouse where harvested produce is stored.
______41.
Evade the pathogen by planting earlier or later than usual.
______42.
Good sanitation practices including removing crop debris from the field or from
underneath the plant.
______43.
Improve the vigor of the plant so it has increased resistance to attack from
pathogens.
______44.
Produce seed in the Northwestern United States where the climate is unsuitable
for pathogens that would attack the seed.
______45.
Reflective mulches.
______46.
Rogue the plant or entire crop.
______47.
Spraying harvested fruit with antagonistic microbes.
______48.
Systemic acquired resistance.
______49.
The Plant Quarantine Act of 1912.
______50.
Use of resistant varieties.
17
Chapter 10 Environmental Factors that Cause Disease
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. Each question is worth ½ point.
______51.
How do high temperatures damage plants?
A. Damage membranes.
B. Denature proteins.
C. Inactivate or accelerate enzyme systems.
D. All of the above.
______52.
How do chilling temperatures damage plants?
A. Cause insect vectors to remain on the plant for a longer amount of time.
B. Damage membranes.
C. Formation of razor-sharp ice crystals that pierce cells and tissues.
D. Inactivate chloroplasts.
______53.
How do freezing temperatures damage plants?
A. Damage cell membranes.
B. Formation of razor-sharp ice crystals that pierce cells and tissues.
C. Shrink chloroplasts.
D. Answers b and c.
True/false questions. Please read each question carefully, then on the line next to the question
write T if the statement is True or F if the statement is false. Each question is worth ½ point.
______54.
Leaf scorch and wilting are examples of injuries caused by moisture stress.
______55.
Humans can cause plant abiotic diseases.
______56.
Low temperature damages more crops than high temperature, but high
temperature usually results in faster, greater damage than low temperature.
______57.
Air pollution may directly cause plant disease.
______58.
Excessive levels of essential elements usually cause direct damage to plant cells.
______59.
Low relative humidity is usually a greater problem outdoors than indoors.
______60.
High relative humidity can increase transpiration and result in increased uptake of
nutrients.
18
Handouts and Guest Speakers
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. Each question is worth ½ point.
______61.
The nematodes that attacked much of Arkansas’ cotton crop in October were
more destructive because
A. The plants had underdeveloped root systems due to early rains and saturated
soils.
B. Most of the growers planted a high-yielding but susceptible variety of cotton.
C. Researchers mistakenly thought early symptoms of damage were caused by
excessive use of an ammonia fertilizer.
D. All of the above.
______62.
The botanical control measure favored by organic farmer Susan Zidlicky, who
was a recent guest speaker, is
A. Fertilizer manufactured from alfalfa.
B. Mulch.
C. Neem oil.
D. All of the above.
True/false questions. Please read each question carefully, then on the line next to the question
write T if the statement is True or F if the statement is false. Each question is worth ½ point.
______63.
Guest speaker Gaylord Moore said good sanitation including removal of debris
from the ground is important to prevent diseases, and that he burns his plant
debris instead of composting it or plowing it under.
______64.
Gaylord Moore said that soil solarization is seldom effective in the Ozarks to
control soil-borne pathogens because of the heavy clay and hardpan soils.
______65.
The USDA, EPA and the Customs Service regulate genetically engineered
organisms and products in the United States.
______66.
Transgenic plants have been exempted from the list of genetically engineered
products regulated by federal and state agencies.
______67.
Scientists and companies do not need approval to develop and test genetically
engineered plants, but must obtain permits before such plants can be marketed
and sold in the United States.
______68.
The ‘unknown malady’ plaguing part of Arkansas’ rice crop
this summer
was
Version
A
caused by a herbicide widely used by rice farmers.
AGH 483
19
Exam 3
13 Dec. 2004
2.3 bonus points are built into this 33-point exam
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. Each question is worth 1/3 point.
______1. This pathogen is responsible for ergot.
A.
Botrytis cineraria.
B.
Claviceps purpurea.
C.
Venturia inaequalis.
D.
Xanthomonas ergotia.
______2.
Most fungi reproduce primarily by
A.
Asexual reproduction.
B.
Formation of spores.
C.
Sexual reproduction.
D.
Both b and c.
______3.
This fungus is probably the most common and widely-distributed disease of vegetables,
ornamentals, fruits and some field crops.
A.
Botrytis.
B.
Ergot.
C.
Erwinia.
D.
Pseudomonas.
______4.
This disease is sometimes called gray mold.
A.
Botrytis.
B.
Ergot.
C.
Erwinia.
D.
Pseudomonas.
______5.
Fusarium and Verticillium pathogens cause this type of disease.
A.
Galls.
B.
Leaf spots or blights.
C.
Rusts.
D.
Vascular wilts.
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement
is True or F if the statement is false. Each question is worth 1/3 point.
______6.
Gymnosporangium is the fungal pathogen that causes Cedar-Apple Rust.
20
______7.
Phakospora is the fungal pathogen that causes Asian Soybean Rust.
______8.
Puccinia causes smut in corn and other plants.
______9.
Pythium is a soil-borne bacterium that can cause blight on turfgrass and can cause
rotting on soft, fleshy vegetables in contact with the soil.
______10. Late Blight of Potato is more destructive in areas with cool but dry weather.
______11. Phytophthora infestans overwinters as mycelium in infected potato tubers.
______12. Rhizopus causes soft rots on fruits and vegetables. This fungal pathogen excretes
enzymes to break down cellulose of plant cell walls.
______13. The Taphrina fungus induces excessive cell enlargement and cell division in its hosts,
causing leaf, flower and fruit deformation on stone fruit and forest trees.
______14. Powdery mildew can be wiped off of affected plant leaves, so chemical treatment is
unnecessary.
______15. Spores of the Alternaria fungus are so small they can be carried by air currents, and are
one of the most common fungal causes of hay fever allergies.
______16. Anthracnose is often found on Hostas.
______17. Since ergot can cause gangrenous, convulsive and hallucinogenic symptoms in humans
and animals, it should never be ingested, even in extremely small quantities.
Matching. Place the letter of the phrase that best matches the description in the space next to the description. Each
question worth 1/3 point.
A. Asexual reproductive structures.
B. Sexual reproductive structures.
C. Vegetative structures.Ascospore.
______18. Conidia.
______20. Mycelium.
______19. Hyphae.
______21. Sclerotia.
Chapter 12
Plant Diseases Caused by Bacteria
Multiple choice. Please read the question carefully then write the letter of the answer that best completes the statement on the line in
front of the question. Each question is worth 1/3 point.
______22. Fire blight is caused by the bacterium
A.
Clavibacter michiganense.
B.
Erwinia amylovora.
C.
Pseudomonas syringae.
D.
Xanthomonas campestris.
21
______23. Yellows diseases are caused by
A.
Bacterial leaf blight pathogens.
B.
Fastidious vascular bacteria.
C.
Ice nucleating agents.
D.
Spiroplasmas or phytoplasmas.
______24. Water-soaked spots, with or without a yellow halo, are common on plant leaves infected by
bacteria. The spots probably look water-soaked because
A.
Bacteria destroyed cells and cell contents have leaked out.
B.
Saphrophic pathogens are attacking the plant tissue.
C.
The plant and pathogen are entering into a symbiotic relationship.
D.
The plant is defending itself against the bacteria by depositing oily substances around
sites of infection.
______25. The most common symptom caused by plant bacterial diseases is
A.
Crown or root galls.
B.
Leaf spots.
C.
Soft rots.
D.
Vascular wilts.
______26. Bacterial cell walls are usually surrounded by a viscous, gummy material called
A.
Cytoplasm.
B.
Mollicute.
C.
Sclerotium.
D.
Slime layer.
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is
True or F if the statement is false. Each question is worth 1/3 point.
______27.
Some pathogenic bacteria secrete pectinases to break down a plant’s cell wall.
______28.
The mere exponential multiplication of bacteria inside a plant can cause crowding of
cells and tissues, causing a collapse and rupturing of plant cells.
______29.
Plant mitochondria and chloroplasts may have evolved from bacteria.
______30.
Pseudomonas and Xanthomonas are the primary genera of bacteria that cause spots and
blights of plant leaves, stems and fruits.
______31.
Soft rot bacteria such as Erwinia and Pseudomonas produce enzymes that dissolve the
middle lamella in fleshy plant tissues.
______32.
Canker-causing bacteria overwinter in active cankers, infected buds and leaves, as
epiphytes on buds and limbs, and possibly on weeds.
______33.
INA bacteria help prevent freezing injury on woody ornamentals.
22
Chapter 13 Plant Diseases Caused by Parasitic Higher Plants
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is
True or F if the statement is false. Each question is worth 1/3 point.
______34.
Dodder is a slender, twining plant with lance-shaped leaves about ¼ inch long.
______35.
Dodder overwinters as hard masses of sclerotia.
______36.
Once dodder comes in contact with a susceptible plant, it sends haustoria inside the leaf
or stem to absorb food and water.
______37.
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.
______38.
The best control method for dodder is the use of resistant crop plants.
______39.
Mistletoe produces both male and female plants, and the female plants are the ones that
have berries.
______40.
Mistletoe is spread by both active and passive dissemination.
______41.
Dodder may vector viruses.
Chapter 14 Diseases Caused by Viruses
Multiple choice. Read the questions carefully, then place the letter of the best answer
in the space next to the question. 1/3 point each.
______42.
The two main components of viruses are
A.
Carbohydrates and proteins.
B.
Flagella and nucleic acid.
C.
Mosaics and mottling.
D.
Protein coat and nucleic acid.
______43.
Ways in which viruses are transmitted from plant to plant include
A.
Direct puncturing ability via a penetration peg.
B.
Fission.
C.
Flagella and nucleic acid.
D.
Insect vectors.
______44.
How do viruses affect the physiology of plants to produce disease symptoms?
23
A.
B.
C.
D.
Probably virus-induced synthesis of new proteins by the host, some of which are
biologically active substances (enzymes, etc.) that may interfere with normal
metabolism.
Decrease in photosynthesis and chlorophyll.
Decrease in growth hormones and an increase in growth inhibitors.
All of the above.
True or false. 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. 1/3 point each.
______45.
Viruses can be characterized as transparent, obligate parasites.
______46.
A virion is a complete virus particle.
______47.
Plant respiration usually decreases immediately after the onset of a viral infection.
______48.
Plant viruses are usually named based on the host plant where they were first found
symptoms produced.
______49.
One of the drawbacks to the virus nomenclature system is that viruses frequently lose
their ability to infect a previously susceptible host species.
______50.
Viruses sometimes produce inoculum on the surface of plants.
______51.
Viruses are always spread by insect vectors.
Chapter 15 Plant Diseases Caused by Nematodes
Read the questions carefully, then place the letter of the best answer in the space next
to the question. 1/3 point each.
______52.
Which of the following statements about nematodes is incorrect?
A. Females of some species are pear-shaped at maturity.
B. Nematodes are visible with a microscope.
C. Nematodes are wormlike but are not true worms.
D. While nematodes cause $80 billion in crop losses annually, most species of
nematodes are considered beneficial organisms in agriculture.
______53.
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 six pairs of 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. All of the above.
24
Read each question carefully, then print a T on the line next to the question of the
statement is true, or an F on the line if the statement is false.1/3 point each.
______54.
Female nematodes can produce fertile eggs after mating with a male or in the absence of
a male.
______55.
The eggs of some species of nematodes can remain dormant in the soil for years while
waiting for a susceptible host plant.
______56.
Nematodes can only survive in the top 15-30 cm of soil.
______57.
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.
______58.
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.
______59.
Some nematode species attack stems or leaf surfaces, rather than roots.
______60.
Nematodes vector some viruses including tomato ringspot.
Handouts and Guest Speakers
Tom Hansen—Row Crop diseases
Multiple choice questions. Please read each question carefully then write the letter of the answer that best completes the statement on the
line in front of the question. Each question is worth 1/3 point.
______61.
Seed decay and seedling blights, caused by fungi, are probably the worst problems for
Missouri corn farmers. These diseases are favored by
A.
Cool, dry weather.
B.
Cool, wet weather.
C.
Warm, dry weather.
D.
Warm, wet weather.
______62.
Corn crops are usually more susceptible to the seed decay and seedling blight pathogens
because farmers tend to
A.
Overfertilize.
B.
Plant early.
C.
Plant late.
D.
Underwater.
______63.
Which method was NOT recommended to control or prevent seedling blights of corn?
A.
Choosing resistant varieties.
25
B.
C.
D.
Making sure soils have good fertility, especially proper levels of P (phosphorus)
and K (potassium).
Planting seed that was saved from the previous season’s corn crop.
Treating seed with fungicides.
______64.
Scab is one of the worst problems in wheat grown in Southwest Missouri. Which of the
following statements about scab on wheat is true?
A.
Crop rotation for at least one year is among the ways to manage this disease.
B.
Symptoms are first seen as bleached areas on the head (grain).
C.
The disease is favored by wet conditions when the crop is flowering.
D.
All of the above are true.
______65.
What type of mycotoxin (toxin produced by a plant pathogenic fungus) is found in
wheat infected with scab?
A.
Aspergillus.
B.
Triticigillus.
C.
Vomitoxin.
D.
Zeatoxin.
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is true or F if
the statement is false. Each question is worth 1/3 point.
______66.
Pathogens that cause rust diseases overwinter in crop debris.
______67.
Soybean rust is most often controlled in the United States with the use of resistant
varieties.
Dr. Laszlo Kovacs—Crown Gall Disease and Its Causal Agent Agrobacterium tumefaciens
Multiple choice. Please read the question carefully then write the letter of the answer that best completes the statement on the line in
front of the question. Each question is worth 1/3 point.
______68.
What chemical weapon is used by most bacteria that cause rot diseases?
A.
Enzymes.
B.
Hormones.
C.
Polysaccharides.
D.
Proteins.
______69.
The compounds that Agrobacterium tumefaciens forces a plant to produce as a source
of nutrition for the bacterium are called
A.
Auxins.
B.
Opines.
C.
Phenolics.
D.
Ti-plasmid.
26
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is true or F if
the statement is false. Each question is worth 1/3 point.
______70.
Agrobacterium tumefaciens can transform a plant cell only if the cell is in the healing
phase after a wound.
______71.
Crown Gall Disease usually occurs in woody plant species but seldom in annuals.
______72.
Agrobacterium radiobacter Strain K84, which produces the antibiotic agrocin 84, is
effective at curing plants infected with Crown Gall Disease.
______73.
Scientists involved in genetic engineering can use the plasmid from A. tumefaciens to
vector new, desired genes into plants, animals and other life forms.
Ed Halasey and Leann Schmidt—Turfgrass Diseases
Multiple choice. Please read the question carefully then write the letter of the answer that best completes the statement on the line in
front of the question. Each question is worth 1/3 point.
______74.
In most turfgrass diseases, this is the key aspect of the disease triangle that is most likely
manipulated to control or prevent diseases.
A.
Environment.
B.
Host.
C.
Pathogen.
D.
Time.
______75.
This disease is most commonly found on turfgrasses that are low in nitrogen, and on dry
soil during periods of warm, humid weather, especially in spring and fall when heavy
dews occur.
A.
Brown patch.
B.
Dollar spot.
C.
Spring dead spot.
D.
Pythium blight.
______76.
This turfgrass disease typically occurs following late summer nitrogen applications,
abundant fall moisture, and low temperatures in winter.
A.
Brown patch.
B.
Dollar spot.
C.
Spring dead spot.
D.
Pythium blight.
27
Dr. Wenping Qiu—Diagnosis of Plant Viral Diseases
Multiple choice. Please read the question carefully then write the letter of the answer that best completes the statement on the line in
front of the question. Each question is worth 1/3 point.
______77.
Localized symptoms of viral infections include
A.
Chlorosis.
B.
Ring spots.
C.
Mosaic or mottling.
D.
Wilt.
______78.
ELISA is a/an ___________-based method to identify a virus causing a disease in a
specific plant.
A.
Bio-index.
B.
Nucleic acid.
C.
Protein.
D.
RNA or DNA.
______79.
PCR (polymerase chain reaction) is a/an ___________-based method to identify a virus
causing a disease in a specific plant.
A.
Bio-index.
B.
Inoculation.
C.
Nucleic acid.
D.
Protein.
Larry Ryan—Diseases in the Landscape
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is true or F if
the statement is false. Each question is worth 1/3 point.
______80.
It is important to prune apple trees to Improve air movement and light penetration.
______81.
When chemicals are used to control diseases of trees in the landscape, timing of
applications is the most critical factor.
______82.
Larry Ryan, owner of Ryan’s Landscape Service, calls chemicals ‘labor-saving products’
instead of pesticides, when talking to clients.
______83.
Fungicide injections are ineffective at controlling certain tree diseases.
______84.
Trenching is a technique to prevent the spread of diseases from tree to tree because the
trench prevents water-borne spores from reaching the uninfected tree.
______85.
Trees infected with Dutch Elm Disease should be cut down, but homeowners can retain
the cut limbs for firewood.
28
Asian Soybean Rust
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is true or F if
the statement is false. Each question is worth 1/3 point.
______86.
Asian soybean rust is vectored by a beetle.
______87.
Asian soybean rust was found on soybeans this fall in at least eight U.S. southern and
Delta states.
Questions Commonly Missed on Previous Quizzes and Exams
Multiple choice. Please read the question carefully then write the letter of the answer that best completes the statement on the line in
front of the question. Each question is worth 1/3 point.
______88.
Which of the following disease categories is considered the most useful?
A.
Plant organ the disease affects.
B.
Symptoms the disease causes.
C.
Type of pathogen.
D.
Types of plants affected.
______89.
Soft rot pathogens typically use which type of chemical weapon to obtain nutrition from
harvested fruits and vegetables?
A.
Enzymes.
B.
Growth regulators.
C.
Polysaccharides.
D.
Toxins.
______90.
Fungi sometimes produce this enzyme to penetrate the plant surface.
A.
Cutinase.
B.
Gluconase.
C.
Pectinase.
D.
Polysaccharase.
______91.
The main goal of any disease control program is to eliminate or reduce
A.
All signs of pathogens.
B.
Stress to the plant.
C.
Dehydration.
D.
One of the factors in the disease triangle.
______92.
What does ubiquitous mean?
A.
Especially virulent.
B.
Found everywhere.
C.
Long-lived.
29
D.
Race or strain of a nonpathogenic species of fungus.
______93.
How do chilling temperatures damage plants?
A.
Cause insect vectors to remain on the plant longer than usual.
B.
Damage membranes.
C.
Formation of razor-sharp ice crystals that pierce cells and tissues.
D.
Inactivate chloroplasts.
______94.
According to MU Horticulture Extension Specialist Gaylord Moore, what common
ingredient is used to treat bacterial diseases?
A.
Baking soda.
B.
Copper.
C.
Iron.
D.
Sevin dust.
True/false questions. Please read each question carefully, then on the line next to the question write T if the statement is true or F if
the statement is false. Each question is worth 1/3 point.
______95.
The fungi that cause white rot in woody species primarily use enzymes to degrade lignin
and other plant cell wall components.
______96.
The hypersensitive response is when a plant rapidly synthesizes substances to reinforce
cell walls to make penetration of the pathogen more difficult.
______97.
Suppressive soils prevent the development of soilborne pathogens that cause severe
diseases.
______98.
As long as plants and pathogens can be kept away from one another, no disease will
develop.
______99.
Transgenic plants have been exempted from the list of genetically engineered products
regulated by federal and state agencies.
______100.
Scientists and companies do not need approval to develop and test genetically
engineered plants, but must obtain permits before such plants can be marketed and sold
in the United States.
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. 1/3 point each.
A.
B.
C.
D.
E.
F.
G.
H.
I.
Anthracnose
Blight
Callus
Canker
Gall
Mosaic
Ring Spot
Rosette
Russeting
J. Rust
K. Water soaking
L. Witches’ broom
30
______101.
Circular line patterns usually caused by a virus.
______102.
Bronzing or browning and roughening of the surface; usually on fruit.
______103.
Disease introduced to the United States that is killing American dogwoods (Cornus
florida).
______104.
Rapid killing of plant tissue.
______105.
Refers to a fungus and is actually a sign.
______106.
Spot on the leaf that appears ‘greasy’ or wet.
31