Pathology L5 Management

Question 1

Epidemiology

Answer 1

The study of epidemics and the factors that affect them (summarized by disease triangle)

Question 2

Epidemiology disease triangle

Answer 2

Includes conducive environmental conditions, susceptible host, and pathogen source of inoculum

Question 3

Epidemic

Answer 3

The increase of disease in a plant population or the dynamics of change in plant disease in space and time

Question 4

Southern leaf corn blight epidemic

Answer 4

June 15-sept 1, 1970
Caused by cochliobolus heterostrophus and spread very quickly

Question 5

What was added to the disease triangle after the southern leaf corn blight epidemic

Answer 5

Time

Question 6

Inoculum

Answer 6

Any part of a pathogen that can initiate disease

Question 7

Examples of an inoculum

Answer 7

Spores, sclerotia, mycelium

Question 8

Primary inoculum

Answer 8

Inoculum that initiates the disease

Question 9

Example of primary inoculum

Answer 9

Ascospores

Question 10

Secondary inoculum

Answer 10

Inoculum produced by infections that take place during same growing season

Question 11

Examples of secondary inoculum

Answer 11

Conidia
Pycnidiospores

Question 12

3 types of disease cycles

Answer 12

Monocyclic disease
Polycyclic disease
Polyetic disease

Question 13

Monocyclic disease

Answer 13

One disease cycle per growing season

Question 14

Polycyclic disease

Answer 14

Multiple disease cycles in a growing season

Question 15

Polyetic disease

Answer 15

Epidemic over a period of many growing seasons

Question 16

When does the sexual stage occur and the inoculum released in monocyclic diseases

Answer 16

Sexual stage occurs in fall or spring
Inoculum is released in spring

Question 17

Primary inoculum in monocyclic disease

Answer 17

Sexual spores

Question 18

When does the asexual/secondary inoculum stage occur in Polycyclic disease

Answer 18

During the growing season

Question 19

What is needed for a disease to occur in a field

Answer 19

Disease must enter field
Field must contain susceptible hosts
Inoculum must be released, transported, or deposited

Question 20

How can inoculum be dispersed

Answer 20

Rain/irrigation splash
Air currents
Infected seeds/pollen/plant matter
Vectors

Question 21

What is integrated pest management

Answer 21

The selection, integration, and use of pest management techniques based on economic, aesthetic,sociological, and ecological consequences

Question 22

IPM components

Answer 22

Scouting
Obtaining information
Exclusion
Cultivar choice
Cultural controls
Chemical controls
Biological controls
Decision support systems

Question 23

Field scouting

Answer 23

Going through the field to determine what diseases are present and is required to identify the pest and the severity of the infection/infestation

Question 24

Scouting in the spring

Answer 24

Examine crop residue and look for signa of pathogens

Question 25

Scouting in the summer

Answer 25

Identify disease and support foliar fungicide application decisions

Question 26

Scouting pre and post harvest

Answer 26

Investigate cause of diseased plants, and determine effectiveness of disease management program to plan for next season

Question 27

How many locations should be scouted in a field of 80-100 acres

Answer 27

5+ locations

Question 28

How many locations should be scouted per quarter section (160 acres)

Answer 28

10+ locations

Question 29

You _________ scout field margins

Answer 29

Should not

Question 30

Reasons for randomly distributed symptoms

Answer 30

Biotic and spreading to nearby plants
Abiotic or genetic

Question 31

Reasons for symptoms most abundant near field edge

Answer 31

Herbicide drift
Diseases moving in from the headlands

Question 32

Reasons for linear or repetitive symptoms

Answer 32

Agronomic
Abiotic stress
Herbicide damage

Question 33

What comes after scouting

Answer 33

Identification

Question 34

Steps in identification

Answer 34

Field history
Past and current agronomic practices
Identifiy

Question 35

Risk of disease increases with….

Answer 35

Poor seed quality
Rotation is short
Field is adjacent to infected field
Variety is susceptible
Fertility and moisture levels are high

Question 36

What does a field history include

Answer 36

Environmental stress
Nutrient deficieny/toxicity
Herbicide injury
Insect damage
Genetic off-types

Question 37

Exclusion

Answer 37

Preventing disease from entering the field through careful sanitation and moving of soil or vegetation

Question 38

What is the Canadian food inspection agency responsible for

Answer 38

Protecting Canada’s plant life and ag by preventing the import/export/establishment of pests and controlling and eradicating pest present in canada

Question 39

Cultivar choice

Answer 39

Selecting varieties resistant to diseases in your area

Question 40

Cultural control

Answer 40

Methods that prevent conditions for disease and other pests from becoming established

Question 41

Crop rotation

Answer 41

Rotating crops planted in the field to reduce availability of susceptible hosts to pathogens in the field

Question 42

First reliable chemical control of plant pathogens

Answer 42

Bordeaux mixture (copper sulfate, lime, and water)

Question 43

How many classes of fungicide

Answer 43

13 modes of action classes

Question 44

Considerations of foliar fungicides

Answer 44

Causes of disease, time to/between scouting, when and what to apply, varietal differences, fertility impact on disease, yield potential

Question 45

How are disease surveys interpreted

Answer 45

Prevalence- # of fields with disease
Incidence- # of infected plants
Severity- strength of disease
Distribution - locations of symptomatic plants